bq27500
bq27501
System-Side Impedance Track™ Fuel Gauge
SLUS785–SEPTEMBER 2007
1 INTRODUCTION
1.1 FEATURES
1.2 APPLICATIONS
•
Battery Fuel Gauge for 1-Series Li-Ion
Applications
•
•
•
•
•
Smartphones
PDAs
•
Resides on System Main Board
Digital Still and Video Cameras
Handheld Terminals
MP3 or Multimedia Players
–
Works with Embedded or Removable
Battery Packs
•
•
Two Varieties
–
bq27500: Uses PACK+, PACK-, and T
Battery Terminals
1.3 DESCRIPTION
–
bq27501: Includes Battery Pack ID Resistor
(RID) Terminal
The Texas Instruments bq27500/01 System-Side
Li-Ion Battery Fuel Gauge is a micro-controller
peripheral that provides fuel gauging for single cell
Li-Ion battery packs. The device requires little system
Micro-Controller Peripheral Provides:
–
–
Accurate Battery Fuel Gauging
Internal Temperature Sensor for System
Temperature Reporting
micro-controller
firmware
development.
The
bq27500/01 resides on the system’s main board, and
manages an embedded battery (non-removable) or a
removable battery pack.
–
–
–
–
Battery Low Interrupt Warning
Battery Insertion Indicator
Battery ID Detection
96 bytes of Non-Volatile Scratch Pad
FLASH
The bq27500/01 uses the patented Impedance
Track™ algorithm for fuel gauging, and provides
information such as remaining battery capacity
(mAh), state-of-charge (%), run-time to empty (min.),
battery voltage (mV), and temperature (°C).
•
Battery Fuel Gauge Based on Patented
Impedance Track™ Technology
–
Models the Battery Discharge Curve for
Accurate Time-to-Empty Predictions
Battery fuel gauging with the bq27500 requires only
PACK+ (P+), PACK- (P-), and Thermistor (T)
connections to
embedded battery circuit. The bq27501 works with
identification resistors in battery packs, to gauge
batteries of different fundamental chemistries and/or
significantly different rated capacities.
–
Automatically Adjusts for Battery Aging,
Battery Self Discharge, and
a
removable battery pack or
Temperature/Rate Inefficiencies
–
Low Value Sense Resistor (10mΩ or Less)
•
•
I2C™ Interface for Connection to System
Micro-Controller Port
12-Pin 2,5 mm × 4,0 mm SON Package
TYPICAL APPLICATION
Host System
LDO
Single Cell Li-Ion
Battery Pack
Voltage
Sense
PACK+
RID
Battery
Low
Warning
PROTECTION
IC
RID
Sense*
Temp
Sense
Power
Management
Controller
I2C
T
bq27500/1
CHG
DSG
Battery
Good
FETs
PACK-
Current
Sense
* bq27501 Only
Please be aware that an important notice concerning availability, standard warranty, and use in critical applications of Texas
Instruments semiconductor products and disclaimers thereto appears at the end of this document.
Impedance Track is a trademark of Texas Instruments.
I2C is a trademark of Philips Electronics.
UNLESS OTHERWISE NOTED this document contains
PRODUCTION DATA information current as of publication date.
Products conform to specifications per the terms of Texas
Instruments standard warranty. Production processing does not
necessarily include testing of all parameters.
Copyright © 2007, Texas Instruments Incorporated
Download from Www.Somanuals.com. All Manuals Search And Download.
bq27500
bq27501
System-Side Impedance Track™ Fuel Gauge
SLUS785–SEPTEMBER 2007
2 DEVICE INFORMATION
2.1 AVAILABLE OPTIONS
COMMUNICATION
FORMAT
TAPE and REEL
QUANTITY
(1)
PART NUMBER
PACKAGE
TA
bq27500DRZR
bq27500DRZT
bq27501DRZR(2)
bq27501DRZT(2)
3000
300
12-pin, 2,5 mm x 4,0 mm
SON
–40°C to 85°C
I2C
3000
300
(1) For the most current package and ordering information, see the Package Option Addendum at the end of this document, or see the TI
(2) Product Preview
2.2 PIN DIAGRAMS
12
11
10
9
1
2
3
4
5
6
BAT_GD
SCL
12
11
10
9
BAT_LOW_
BI/TOUT
TS
BAT_GD
SCL
BAT_LOW_
BI/TOUT
TS
1
2
3
4
5
6
SDA
SDA
NC
bq27501
bq27500
RID
BAT
BAT
8
SRN
SRP
SRN
SRP
8
VCC
VSS
VCC
VSS
7
7
2.3 TERMINAL FUNCTIONS
TERMINAL
I/O(1)
DESCRIPTION
NAME
NAME
PIN NO.
bq27500
bq27501
Battery Low output indicator. Active high by default, though polarity can be configured
through the [BATL_POL] in Operation Configuration Push-pull output.
1
2
BAT_LOW BAT_LOW
O
Battery-insertion detection input. Power pin for pack thermistor network. Thermistor
multiplexer control pin. Open-drain I/O. use with pull-up resistor > 1MΩ (1.8MΩ typical)
BI/TOUT
BI/TOUT
I/O
3
4
5
6
TS
TS
P
I
Pack thermistor voltage sense (use 103AT-type thermistor). ADC input.
Cell-voltage measurement input. ADC input.
BAT
VCC
VSS
BAT
VCC
VSS
P
P
Processor power input. Decouple with 0.1μF capacitor, minimum.
Device ground.
Analog input pin connected to the internal coulomb-counter where SRP is nearest the
CELL- connection. Connect to 5-20mΩ sense resistor.
7
8
SRP
SRP
IA
IA
–, I
I/O
I
Analog input pin connected to the internal coulomb-counter where SRN is nearest the
PACK- connection. Connect to 5-20mΩ sense resistor.
SRN
NC
SRN
RID
No connection (bq27500). Resistor ID input (bq27501). Analog input with current sourcing
capabilities.
Slave I2C serial communications data line for communication with system (Master).
Open-drain I/O. Use with 10kΩ pull-up resistor (typical).
Slave I2C serial communications clock input line for communication with system (Master).
9
10
11
12
SDA
SDA
SCL
SCL
Open-drain I/O. Use with 10kΩ pull-up resistor (typical).
Battery Good indicator. Active low by default, though polarity can be configured through
the [BATG_POL] of Operation Configuration. Open-drain output.
BAT_GD
BAT_GD
O
(1) I/O = Digital Input/Output, IA = Analog Input, P = Power Connection
Submit Documentation Feedback
DEVICE INFORMATION
3
Download from Www.Somanuals.com. All Manuals Search And Download.
bq27500
bq27501
System-Side Impedance Track™ Fuel Gauge
SLUS785–SEPTEMBER 2007
3 ELECTRICAL SPECIFICATIONS
3.1 ABSOLUTE MAXIMUM RATINGS
over operating free-air temperature range (unless otherwise noted)(1)
PARAMETER
VALUE
–0.3 to 2.75
–0.3 to 6
UNIT
V
VCC
VIOD
VBAT
VI
Supply voltage range
Open-drain I/O pins (BI_TOUT, SDA, SDL, BAT_GD)
BAT input pin
V
–0.3 to +6
Input voltage range to all other pins (TS, SRP, SRN, RID [bq27501 only], NC
[bq27500 only])
–0.3 to VCC + 0.3
V
1
kV
kV
°C
°C
ESD
Human Body Model (HMB)
2
TF
Functional temperature range
Storage temperature range
–40 to 100
–65 to 150
TSTG
(1) Stresses beyond those listed under absolute maximum ratings may cause permanent damage to the device. These are stress ratings
only, and functional operation of the device at these or any other conditions beyond those indicated under recommended operating
conditions is not implied. Exposure to absolute-maximum-rated conditions for extended periods may affect device reliability.
3.2 RECOMMENDED OPERATING CONDITIONS
TA = 25°C, VCC = 2.5 V (unless otherwise noted)
PARAMETER
TEST CONDITIONS
MIN
TYP
2.5
95
15
2
MAX UNIT
VCC
ICC
Supply Voltage
2.4
2.6
V
μA
μA
μA
V
Normal operating mode current(1)
Low-power storage mode current(2)
Hibernate operating mode current(3)
ISLP
ICC
VOL
Output voltage low (SDA, BAT_LOW, BI/TOUT) IOL = 0.5 mA
0.4
VOH(PP)
Output high voltage (BAT_LOW)
IOH = –1 mA
VCC–0.5
VCC–0.5
V
External pull-up resistor
connected to VCC
VOH(OD)
Output high voltage (SDA, SCL, BI/TOUT)
V
V
VIL
Input voltage low (SDA, SCL)
Input voltage high (SDA, SCL, BI/TOUT)
Input capacitance
–0.3
2
0.8
6
VIH(OD)
CIN
5
pF
V
VA1
Input voltage range (TS, RID [bq27501 only])
Input voltage range (BAT)
VSS–0.125
VSS–0.125
VSS–0.125
2
5
VA2
V
VA3
Input voltage range (SRP, SRN)
Power up communication delay
Operating free-air temperature range
0.125
V
tPUCD
TA
250
ms
°C
–40
85
(1) High level of system activity.
(2) Low level of system activity.
(3) Fuel gauge algorithm power inactive. Only able to receive I2C communication.
3.3 POWER-ON RESET
TA = –40°C to 85°C, Typical Values at TA = 25°C and VBAT = 3.6 V (unless otherwise noted)
PARAMETER
TEST CONDITIONS
MIN
2.09
45
TYP
MAX
2.31
185
UNIT
V
VIT+
Positive-going battery voltage input at VCC
2.20
115
VHYS
mV
4
ELECTRICAL SPECIFICATIONS
Submit Documentation Feedback
Download from Www.Somanuals.com. All Manuals Search And Download.
bq27500
bq27501
System-Side Impedance Track™ Fuel Gauge
SLUS785–SEPTEMBER 2007
3.4 INTERNAL TEMPERATURE SENSOR CHARACTERISTICS
TA = –40°C to 85°C, 2.4 V < VCC < 2.6 V; Typical Values at TA = 25°C and VCC = 2.5 V (unless otherwise noted)
PARAMETER
TEST CONDITIONS
MIN TYP
MAX
UNIT
GTEMP
Temperature sensor voltage gain
–2.0
mV/°C
3.5 HIGH FREQUENCY OSCILLATOR
TA = –40°C to 85°C, 2.4 V < VCC < 2.6 V; Typical Values at TA = 25°C and VCC = 2.5 V (unless otherwise noted)
PARAMETER
TEST CONDITIONS
MIN
TYP
MAX
UNIT
fOSC
Operating frequency
2.097
MHz
TA = 0°C to 60°C
–2.0% 0.38% 2.0%
–3.0% 0.38% 3.0%
–4.5% 0.38% 4.5%
(1) (2)
fEIO
Frequency error
Start-up time(3)
TA = –20°C to 70°C
TA = –40°C to 85°C
tSXO
2.5
5
ms
(1) The frequency error is measured from 2.097 MHz.
(2) The frequency drift is included and measured from the trimmed frequency at VCC = 2.5V, TA = 25°C.
(3) The startup time is defined as the time it takes for the oscillator output frequency to be ±3%.
3.6 LOW FREQUENCY OSCILLATOR
TA = –40°C to 85°C, 2.4 V < VCC < 2.6 V; Typical Values at TA = 25°C and VCC = 2.5 V (unless otherwise noted)
PARAMETER
TEST CONDITIONS
MIN
TYP
32.768
0.25%
0.25%
0.25%
MAX UNIT
kHz
fLOSC
Operating frequency
TA = 0°C to 60°C
–1.5%
–2.5%
–4.0%
1.5%
(1) (2)
fLEIO
Frequency error
Start-up time(3)
TA = –20°C to 70°C
2.5%
TA = –40°C to 85°C
4.0%
tLSXO
500
μs
(1) The frequency drift is included and measured from the trimmed frequency at VCC = 2.5V, TA = 25°C.
(2) The frequency error is measured from 32.768 kHz.
(3) The startup time is defined as the time it takes for the oscillator output frequency to be ±3%.
3.7 INTEGRATING ADC (COULOMB COUNTER) CHARACTERISTICS
TA = –40°C to 85°C, 2.4 V < VCC < 2.6 V; Typical Values at TA = 25°C and VCC = 2.5 V (unless otherwise noted)
PARAMETER
Input voltage range, V(SRN) and V(SRP)
Conversion time
TEST CONDITIONS
VSR = V(SRN) – V(SRP)
MIN
TYP
MAX
UNIT
V
VSR_IN
–0.125
0.125
15
tSR_CONV
Single conversion
1
s
Resolution
14
bits
mV
μV
Before calibration
After calibration
1
VSR_OS
Input offset
10
INL
Integral nonlinearity error
Effective input resistance(1)
Input leakage current(1)
±0.007 ±0.034
% FSR
MΩ
μA
ZSR_IN
ISR_LKG
2.5
0.3
(1) Specified by design. Not tested in production.
3.8 ADC (TEMPERATURE AND CELL MEASUREMENT) CHARACTERISTICS
TA = –40°C to 85°C, 2.4 V < VCC < 2.6 V; Typical Values at TA = 25°C and VCC = 2.5 V (unless otherwise noted)
PARAMETER
TEST CONDITIONS
MIN
TYP
MAX
UNIT
VADC_IN
Input voltage range
–0.2
1
V
Submit Documentation Feedback
ELECTRICAL SPECIFICATIONS
5
Download from Www.Somanuals.com. All Manuals Search And Download.
bq27500
bq27501
System-Side Impedance Track™ Fuel Gauge
SLUS785–SEPTEMBER 2007
ADC (TEMPERATURE AND CELL MEASUREMENT) CHARACTERISTICS (continued)
TA = –40°C to 85°C, 2.4 V < VCC < 2.6 V; Typical Values at TA = 25°C and VCC = 2.5 V (unless otherwise noted)
PARAMETER
Conversion time
TEST CONDITIONS
MIN
TYP
MAX
125
UNIT
ms
tADC_CONV
Resolution
Input offset
14
15
bits
mV
MΩ
VADC_OS
ZADC1
1
Effective input resistance (TS, RID
[bq27501 only])
8
8
bq27500/1 not measuring cell voltage
bq27500/1 measuging cell voltage
MΩ
kΩ
μA
ZADC2
Effective input resistance (BAT)(1)
Input Leakage Current(1)
100
IADC_LKG
0.3
(1) Specified by design. Not tested in production.
3.9 DATA FLASH MEMORY CHARACTERISTICS
TA = –40°C to 85°C, 2.4 V < VCC < 2.6 V; Typical Values at TA = 25°C and VCC = 2.5 V (unless otherwise noted)
PARAMETER
Data retention
TEST CONDITIONS
(1)
MIN
10(1)
TYP
MAX
UNIT
Years
Cycles
ms
tON
See
See
See
(1)
(1)
Flash programming write-cycles
Word programming time
20,000
tWORDPROG
ICCPROG
2
Flash-write supply current
5
10
mA
(1) Specified by design. Not production tested
3.10 I2C-COMPATIBLE INTERFACE COMMUNICATION TIMING CHARACTERISTICS
TA = –40°C to 85°C, 2.4 V < VCC < 2.6 V; Typical Values at TA = 25°C and VCC = 2.5 V (unless otherwise noted)
PARAMETER
SCL/SDA rise time
TEST CONDITIONS
MIN TYP
MAX
1
UNIT
μs
tr
tf
SCL/SDA fall time
300
ns
tw(H)
tw(L)
tsu(STA)
td(STA)
tsu(DAT)
SCL pulse width (high)
SCL pulse width (low)
Setup for repeated start
Start to first falling edge of SCL
Data setup time
4
4.7
4.7
4
μs
μs
μs
μs
250
0
ns
Receive mode
Transmit mode
th(DAT)
Data hold time
ns
300
4
tsu(STOP)
tBUF
Setup time for stop
μs
μs
kHz
s
Bus free time between stop and start
Clock frequency
4.7
10
fSCL
100
tBUSERR
Bus error timeout
17.3
21.2
6
ELECTRICAL SPECIFICATIONS
Submit Documentation Feedback
Download from Www.Somanuals.com. All Manuals Search And Download.
bq27500
bq27501
System-Side Impedance Track™ Fuel Gauge
SLUS785–SEPTEMBER 2007
Figure 3-1. I2C-Compatible Interface Timing Diagrams
Submit Documentation Feedback
ELECTRICAL SPECIFICATIONS
7
Download from Www.Somanuals.com. All Manuals Search And Download.
bq27500
bq27501
System-Side Impedance Track™ Fuel Gauge
SLUS785–SEPTEMBER 2007
4 GENERAL DESCRIPTION
The bq27500/1 accurately predicts the battery capacity and other operational characteristics of a single
Li-based rechargeable cell. It can be interrogated by a system processor to provide cell information, such
as State-of-Charge (SOC), Time-to-Empty (TTE) and Time-to-Full (TTF).
Information is accessed through a series of commands, called Standard Commands. Further capabilities
are provided by the additional Extended Commands set. Both sets of commands, indicated by the general
format Command( ), are used to read and write information contained within the bq27500/1 control and
status registers, as well as its data flash locations. Commands are sent from system to gauge using the
bq27500/1’s I2C serial communications engine, and can be executed during application development,
pack manufacture, or end-equipment operation.
Cell information is stored in the bq27500/1 in non-volatile flash memory. Many of these data flash
locations are accessible during application development. They cannot be accessed directly during
end-equipment operation. Access to these locations is achieved by either use of the bq27500/1's
companion evaluation software, through individual commands, or through a sequence of data-flash-access
commands. To access a desired data flash location, the correct data flash subclass and offset must be
known.
The bq27500/1 provides 96 bytes of user-programmable data flash memory, partitioned into 3 32-byte
blocks: Manufacturer Info Block A, Manufacturer Info Block B, and Manufacturer Info Block C. This
data space is accessed through a data flash interface. For specifics on accessing the data flash, see
The key to the bq27500/1’s high-accuracy gas gauging prediction is Texas Instrument’s proprietary
Impedance Track™ algorithm. This algorithm uses cell measurements, characteristics, and properties to
create state-of-charge predictions that can achieve less than 1% error across a wide variety of operating
conditions and over the lifetime of the battery.
The bq27500/1 measures charge/discharge activity by monitoring the voltage across a small-value series
sense resistor (5 mΩ to 20 mΩ typ.) located between the system's Vss and the battery’s PACK– terminal.
When a cell is attached to the bq27500/1, cell impedance is computed, based on cell current, cell Open
Circuit Voltage (OCV), and cell voltage under loading conditions.
The bq27500/1 can use an NTC thermistor (default is Semitec 103AT) for temperature measurement, or
can also be configured to use its internal temperature sensor. The bq27500/1 uses temperature to monitor
the battery-pack environment, which is used for fuel gauging and cell protection functionality.
To minimize power consumption, the bq27500/1 has several power modes: NORMAL, SLEEP,
HIBERNATE, and BAT INSERT CHECK. The bq27500/1 passes automatically between these modes,
depending upon the occurrence of specific events, though a system processor can initiate some of these
NOTE
FORMATTING CONVENTIONS IN THIS DOCUMENT:
Commands: italics with parentheses and no breaking spaces, e.g. RemainingCapacity( ).
Data Flash: italics, bold, and breaking spaces, e.g. Design Capacity
Register Bits and Flags: brackets only, e.g. [TDA]
Data Flash Bits: italics and bold, e.g: [LED1]
Modes and states: ALL CAPITALS, e.g. UNSEALED mode.
8
GENERAL DESCRIPTION
Submit Documentation Feedback
Download from Www.Somanuals.com. All Manuals Search And Download.
bq27500
bq27501
System-Side Impedance Track™ Fuel Gauge
SLUS785–SEPTEMBER 2007
4.1 DATA COMMANDS
4.1.1 STANDARD DATA COMMANDS
The bq27500/1 uses a series of 2-byte standard commands to enable system reading and writing of
battery information. Each standard command has an associated command-code pair, as indicated in
Table 4-1. Because each command consists of two bytes of data, two consecutive I2C transmissions must
be executed both to initiate the command function, and to read or write the corresponding two bytes of
INTERFACE. Standard commands are accessible in NORMAL operation. Read/Write permissions depend
on the active access mode, SEALED or UNSEALED (for details on the SEALED and UNSEALED states,
Table 4-1. Standard Commands
COMMAND
CODE
SEALED
ACCESS
UNSEALED
ACCESS
NAME
UNITS
Control( )
CNTL
AR
0x00 / 0x01
0x02 / 0x03
0x04 / 0x05
0x06 / 0x07
0x08 / 0x09
0x0a / 0x0b
0x0c / 0x0d
0x0e / 0x0f
0x10 / 0x11
0x12 / 0x13
0x14 / 0x15
0x16 / 0x17
0x18 / 0x19
0x1a / 0x1b
0x1c / 0x1d
0x1e / 0x1f
0x20 / 0x21
0x22 / 0x23
0x24 / 0x25
0x26 / 0x27
0x28 / 0x29
0x2a / 0x2b
0x2c / 0x2d
N/A
mA
R/W
R/W
R
R/W
R/W
R
AtRate( )
AtRateTimeToEmpty( )
Temperature( )
ARTTE
TEMP
VOLT
FLAGS
NAC
FAC
RM
Minutes
0.1°K
mV
R
R
Voltage( )
R
R
Flags( )
N/A
R
R
NominalAvailableCapacity( )
FullAvailableCapacity( )
RemainingCapacity( )
FullChargeCapacity( )
AverageCurrent( )
TimeToEmpty( )
mAh
R
R
mAh
R
R
mAh
R
R
FCC
AI
mAh
R
R
mA
R
R
TTE
Minutes
Minutes
mA
R
R
TimeToFull( )
TTF
R
R
StandbyCurrent( )
StandbyTimeToEmpty( )
MaxLoadCurrent( )
MaxLoadTimeToEmpty( )
AvailableEnergy( )
AveragePower( )
SI
R
R
STTE
MLI
Minutes
mA
R
R
R
R
MLTTE
AE
Minutes
10mWhr
10mW
Minutes
N/A
R
R
R
R
AP
R
R
TimeToEmptyAtConstantPower( )
Reserved
TTECP
RSVD
CC
R
R
R
R
CycleCount( )
Counts
%
R
R
StateOfCharge( )
SOC
R
R
Submit Documentation Feedback
GENERAL DESCRIPTION
9
Download from Www.Somanuals.com. All Manuals Search And Download.
bq27500
bq27501
System-Side Impedance Track™ Fuel Gauge
SLUS785–SEPTEMBER 2007
4.1.1.1 Control( ): 0x00/0x01
Issuing a Control( ) command requires a subsequent two-byte sub-command. These additional bytes
specify the particular control function desired. The Control( ) command allows the system to control
specific features of the bq27500 during normal operation and additional features when the bq27500/1 is in
Table 4-2. Control( ) Subcommands
CNTL
DATA
SEALED
ACCESS
CNTL FUNCTION
CONTROL STATUS
DESCRIPTION
0x0000
0x0001
0x0002
0x0003
0x0004
0x0005
0x0006
0x0007
Yes
Yes
Yes
Yes
No
Reports the status of DF Checksum, Hibernate, IT, etc.
Reports the device type (eg: "bq27500")
Reports the firmware version on the device type
Reports the hardware version of the device type
Not to be used
DEVICE TYPE
FW VERSION
HW VERSION
Reserved
RESET DATA
Reserved
No
Returns reset data
No
Not to be used
PREV_MACWRITE
No
Returns previous MAC command code
Reports the chemical identifier of the Impedance Track™
configuration
CHEMID
0x0008
Yes
BOARD OFFSET
CC INT OFFSET
SET HIBERNATE
CLEAR HIBERNATE
SEALED
0x0009
0x000b
0x0011
0x0012
0x0020
0x0021
0x0022
0x0040
0x0041
No
No
Yes
Yes
No
No
No
No
No
Forces the device Board Offset to be measured and stored
Forces the device to measure and store the internal CC offset
Forces DF:Pack Configuration [HIBERNATE] to 1
Forces DF:Pack Configuration [HIBERNATE] to 0
Places the bq27500/1 in SEALED access mode
Enables the Impedance Track™ algorithm
IT ENABLE
IFCHECKSUM
CALMODE
Reports the instruction flash checksum
Places the bq27500/1 in calibration mode
RESET
Forces a full reset of the bq27500/1
4.1.1.1.1 CONTROL STATUS: 0X0000
Instructs the gas gauge to return status information to Control addresses 0x00/0x01. The status word
includes the following information.
Table 4-3. CONTROL STATUS Bit Definitions
Flags( )
High Byte
Low Byte
bit7
–
bit6
FAS
bit5
SS
–
bit4
-
bit3
CCA
bit2
BCA
bit1
–
bit0
–
–
HIBERNATE
SLEEP
LDMD
RUP_DIS
VOK
QEN
FAS = Status bit indicating the bq27500/1 is in FULL ACCESS SEALED state. Active when set.
SS = Status bit indicating the bq27500/1 is in SEALED State. Active when set.
CCA = Status bit indicating the bq27500/1 is Coulomb Counter Calibration routine is active. Active when set.
BCA = Status bit indicating the bq27500/1 Board Calibration routine is active. Active when set.
HIBERNATE = Status bit indicating a request for entry into HIBERNATE from SLEEP mode. True when set. Default is 0.
SLEEP = Status bit indicating the bq27500/1 is in SLEEP mode. True when set. Default is 0.
LDMD = Status bit indicating the bq27500/1 Impedance Track™ algorithm is using constant-power mode. True when set. Default is 0
(constant-current mode)
RUP_DIS = Status bit indicating the bq27500/1 Ra table updates are disabled. Updates disabled when set.
VOK = Status bit indicating the bq27500/1 voltages are OK for QMAX. True when set.
QEN = Status bit indicating the bq27500/1 QMAX updates enabled. True when set.
4.1.1.1.2 DEVICE TYPE: 0x0001
Instructs the fuel gauge to return the device type to addresses 0x00/0x01.
10
GENERAL DESCRIPTION
Submit Documentation Feedback
Download from Www.Somanuals.com. All Manuals Search And Download.
bq27500
bq27501
System-Side Impedance Track™ Fuel Gauge
SLUS785–SEPTEMBER 2007
4.1.1.1.3 FW_VERSION: 0x0002
Instructs the fuel gauge to return the firmware version to addresses 0x00/0x01.
4.1.1.1.4 HW_VERSION: 0x0003
Instructs the fuel gauge to return the hardware version to addresses 0x00/0x01.
4.1.1.1.5 RESET_DATA: 0x0005
Instructs the fuel gauge to return the reset data to addresses 0x00/0x01, with the low-byte being the
number of partial resets and the high-byte the number of full resets.
4.1.1.1.6 PREV_MACWRITE: 0x0007
Instructs the fuel gauge to return the previous command written to addresses 0x00/0x01.
4.1.1.1.7 CHEM ID: 0x0008
Instructs the fuel gauge to return the chemical identifier for the Impedance Track™ configuration to
addresses 0x00/0x01.
4.1.1.1.8 BOARD_OFFSET: 0x0009
Instructs the fuel gauge to compute the coulomb counter offset with internal short and then without internal
short applied across the SR inputs. During this activity, CONROL STATUS [BCA] is set. The difference
between the two measurements is the Board Offset. The Board Offset is written to data flash and is also
returned to addresses 0x00/0x01. The user must prevent any charge or discharge current from flowing
during the process. This function is only available when the fuel gauge is UNSEALED. When SEALED,
this command will only read back the Board Offset value stored in data flash.
4.1.1.1.9 CC_INT_OFFSET: 0x000A
Instructs the fuel gauge to compute the coulomb counter offset with internal short applied across the SR
inputs. The offset value is written to data flash and is also returned to addresses 0x00/0x01. This function
is only available when the fuel gauge is UNSEALED. When SEALED, this command will only read back
the CC_INT_OFFSET value stored in data flash.
4.1.1.1.10 SET_HIBERNATE: 0x0011
Instructs the fuel gauge to force the CONTROL STATUS’ [HIBERNATE] bit to 1. This will allow the gauge
to enter the HIBERNATE power mode after the transition to SLEEP power state is detected. The
[HIBERNATE] bit is automatically cleared upon exiting from HIBERNATE mode.
4.1.1.1.11 CLEAR_HIBERNATE: 0x0012
Instructs the fuel gauge to force the CONTROL STATUS’ [HIBERNATE] bit to 0. This will prevent the
gauge from entering the HIBERNATE power mode after the transition to SLEEP power state is detected. It
can also be used to force the gauge out of HIBERNATE mode.
4.1.1.1.12 SEALED: 0x0020
Instructs the fuel gauge to transition from UNSEALED state to SEALED state. The fuel gauge should
always be set to SEALED state for use in end equipment.
4.1.1.1.13 IT ENABLE: 0x0021
This command forces the fuel gauge to begin the Impedance Track™ algorithm, sets the active
UpdateStatus n location to 0x04 and causes the [VOK] and [QEN] flags to be set in the CONTROL
STATUS register. [VOK] is cleared if the voltages are not suitable for a Qmax update. Once set, [QEN]
cannot be cleared. This command is only available when the fuel gauge is UNSEALED.
4.1.1.1.14 IF CHECKSUM: 0x0022
This command instructs the fuel gauge to compute the instruction flash checksum. When the checksum
has been calculated and stored, then CONTROL STATUS [CVS] is set. In UNSEALED mode, the
checksum value is returned to addresses 0x00/0x01. The checksum will not be calculated in SEALED
mode; however, the checksum value can still be read.
Submit Documentation Feedback
GENERAL DESCRIPTION
11
Download from Www.Somanuals.com. All Manuals Search And Download.
bq27500
bq27501
System-Side Impedance Track™ Fuel Gauge
SLUS785–SEPTEMBER 2007
4.1.1.1.15 CAL MODE: 0x0040
This command instructs the fuel gauge to enter calibration mode. This command is only available when
the fuel gauge is UNSEALED.
4.1.1.1.16 RESET: 0x0041
This command instructs the fuel gauge to perform a full reset. This command is only available when the
fuel gauge is UNSEALED.
4.1.1.2 AtRate( ): 0x02/0x03
The AtRate( ) read-/write-word function is the first half of a two-function command-set used to set the
AtRate value used in calculations made by the AtRateTimeToEmpty( ) function. The AtRate( ) units are in
mA.
The AtRate( ) value is a signed integer, and both positive and negative values will be interpreted as a
discharge current value. The AtRateTimeToEmpty( ) function returns the predicted operating time at the
AtRate value of discharge. The default value for AtRate( ) is zero and will force AtRate( ) to return 65535.
Both the AtRate( ) and AtRateTimeToEmpty( ) commands should only be used in NORMAL mode.
4.1.1.3 AtRateTimeToEmpty( ): 0x04/0x05
This read-word function returns an unsigned integer value of the predicted remaining operating time if the
battery is discharged at the AtRate( ) value in minutes with a range of 0 to 65534. A value of 65535
indicates AtRate( ) = 0. The gas gauge updates AtRateTimeToEmpty( ) within 1s after the system sets the
AtRate( ) value. The fuel gauge automatically updates AtRateTimeToEmpty( ) based on the AtRate( )
value every 1s. Both the AtRate( ) and AtRateTimeToEmpty( ) commands should only be used in
NORMAL mode.
4.1.1.4 Temperature( ): 0x06/0x07
This read-word function returns an unsigned integer value of the temperature in units of 0.1°K measured
by the gas gauge and has a range of 0 to 6553.5°K.
4.1.1.5 Voltage( ): 0x08/0x09
This read-word function returns an unsigned integer value of the measured cell-pack voltage in mV with a
range of 0 to 6000 mV.
4.1.1.6 Flags( ): 0x0a/0x0b
This read-word function returns the contents of the gas-gauge status register, depicting the current
operating status.
Table 4-4. Flags Bit Definitions
bit7
OTC
bit6
OTD
–
bit5
–
bit4
–
bit3
bit2
bit1
FC
bit0
CHG
DSG
High Byte
Low Byte
CHG_INH
BAT_DET
XCHG
SOC1
CC_OFF
OCV_GD
WAIT_ID
SOCF
OTC = Overtemperature in Charge condition is detected. True when set.
OTD = Overtemperature in Discharge condition is detected. True when set.
CHG_INH = Charge Inhibit: unable to begin charging (temp outside the range [Charge Inhibit Temp Low, Charge Inhibit Temp High]).
True when set.
XCHG = Charge Suspend Alert (temp outside the range [Suspend Temp Low, Suspend Temp High]). True when set.
FC = Fully Charged, set when Charge termination condition is met. True when set.
CHG = (Fast)charging allowed. True when set.
CC_OFF = bq27500/1 performing Coulomb Counter Offset measurement. True when set.
OCV_GD = Good OCV measurement taken. True when set.
WAIT_ID = Waiting to identify inserted battery. True when set.
BAT_DET = Battery detected. True when set.
SOC1 = State-of-Charge-Threshold 1 (SOC1 Set) reached. True when set.
SOCF = State-of-Charge-Threshold Final (SOCF Set %) reached. True when set.
DSG = Discharging detected. True when set.
12
GENERAL DESCRIPTION
Submit Documentation Feedback
Download from Www.Somanuals.com. All Manuals Search And Download.
bq27500
bq27501
System-Side Impedance Track™ Fuel Gauge
SLUS785–SEPTEMBER 2007
4.1.1.7 NominalAvailableCapacity( ): 0x0c/0x0d
This read-only command pair returns the uncompensated (no or light load) battery capacity remaining.
Units are mAh per bit.
4.1.1.8 FullAvailableCapacity( ): 0x0e/0x0f
This read-only command pair returns the uncompensated (no or light load) capacity of the battery when
fully charged. Units are mAh per bit. FullAvailableCapacity( ) is updated at regular intervals, as specified
by the IT algorithm.
4.1.1.9 RemainingCapacity( ): 0x10/0x11
This read-only command pair returns the compensated battery capacity remaining. Units are mAh per bit.
4.1.1.10 FullChargeCapacity( ): 0x12/13
This read-only command pair returns the compensated capacity of the battery when fully charged. Units
are mAh per bit. FullChargeCapacity( ) is updated at regular intervals, as specified by the IT algorithm.
4.1.1.11 AverageCurrent( ): 0x14/0x15
This read-only command pair returns a signed integer value that is the average current flow through the
sense resistor. It is updated every 1 second. Units are mA per bit.
4.1.1.12 TimeToEmpty( ): 0x16/0x17
This read-only function returns an unsigned integer value of the predicted remaining battery life at the
present rate of discharge, in minutes. A value of 65535 indicates battery is not being discharged.
4.1.1.13 TimeToFull( ): 0x18/0x19
This read-only function returns an unsigned integer value of predicted remaining time until the battery
reaches full charge, in minutes, based upon AverageCurrent( ). The computation accounts for the taper
current time extension from the linear TTF computation based on a fixed AverageCurrent( ) rate of charge
accumulation. A value of 65535 indicates the battery is not being charged.
4.1.1.14 StandbyCurrent( ): 0x1a/0x1b
This read-only function returns a signed integer value of the measured standby current through the sense
resistor. The StandbyCurrent( ) is an adaptive measurement. Initially it reports the standby current
programmed in Initial Standby, and after spending some time in standby, reports the measured standby
current.
The register value is updated every 1 second when the measured current is above the Deadband (3mA
default) and is less than or equal to 2 x Initial Standby. The first and last values that meet this criteria are
not averaged in, since they may not be stable values. To approximate a 1 minute time constant, each new
StandbyCurrent( ) value is computed as follows:
StandbyCurrent( )NEW = (239/256) × StandbyCurrent( )OLD + (17/256) × AverageCurrent( ).
4.1.1.15 StandbyTimeToEmpty( ): 0x1c/0x1d
This read-only function returns an unsigned integer value of the predicted remaining battery life at the
standby rate of discharge, in minutes. The computation uses Nominal Available Capacity (NAC), the
uncompensated remaining capacity, for this computation. A value of 65535 indicates battery is not being
discharged.
Submit Documentation Feedback
GENERAL DESCRIPTION
13
Download from Www.Somanuals.com. All Manuals Search And Download.
bq27500
bq27501
System-Side Impedance Track™ Fuel Gauge
SLUS785–SEPTEMBER 2007
4.1.1.16 MaxLoadCurrent( ): 0x1e/0x1f
This read-only function returns a signed integer value, in units of mA, of the maximum load conditions.
The MaxLoadCurrent( ) is an adaptive measurement which is initially reported as the maximum load
current programmed in Initial Max Load Current. If the measured current is ever greater than Initial Max
Load Current, then MaxLoadCurrent( ) updates to the new current. MaxLoadCurrent( ) is reduced to the
average of the previous value and Initial Max Load Current whenever the battery is charged to full after
a previous discharge to an SOC less than 50%. This prevents the reported value from maintaining an
unusually high value.
4.1.1.17 MaxLoadTimeToEmpty( ): 0x20/0x21
This read-only function returns an unsigned integer value of the predicted remaining battery life at the
maximum load current discharge rate, in minutes. A value of 65535 indicates that the battery is not being
discharged.
4.1.1.18 AvailableEnergy( ): 0x22/0x23
This read-only function returns an unsigned integer value of the predicted charge or energy remaining in
the battery. The value is reported in units of mWh.
4.1.1.19 AveragePower( ): 0x24/0x25
This read-word function returns an unsigned integer value of the average power of the current discharge.
A value of 0 indicates that the battery is not being discharged. The value is reported in units of mW.
4.1.1.20 TimeToEmptyAtConstantPower( ): 0x26/0x27
This read-only function returns an unsigned integer value of the predicted remaining operating time if the
battery is discharged at the AveragePower( ) value in minutes.
A
value of 65535 indicates
AveragePower( ) = 0. The fuel gauge automatically updates TimeToEmptyatContantPower( ) based on the
AveragePower( ) value every 1s.
4.1.1.21 CycleCount( ): 0x2a/0x2b
This read-only function returns an unsigned integer value of the number of cycles the battery has
experienced with a range of 0 to 65535. One cycle occurs when accumulated discharge ≥ CC Threshold.
4.1.1.22 StateOfCharge( ): 0x2c/0x2d
This read-only function returns an unsigned integer value of the predicted remaining battery capacity
expressed as a percentage of FullChargeCapacity( ), with a range of 0 to 100%.
4.1.2 EXTENDED DATA COMMANDS
Extended commands offer additional functionality beyond the standard set of commands. They are used in
the same manner; however unlike standard commands, extended commands are not limited to 2-byte
words. The number of commands bytes for a given extended command ranges in size from single to
Table 4-5. Extended Data Commands
COMMAND
CODE
SEALED
UNSEALED
NAME
UNITS
ACCESS(1)(2)
ACCESS(1)(2)
Reserved
RSVD
DCAP
0x34...0x3b
0x3c / 0x3d
0x3e
N/A
mAh
N/A
N/A
N/A
N/A
R
R
DesignCapacity( )
DataFlashClass( ) (2)
DataFlashBlock( ) (2)
Authenticate( )/BlockData( )
R
R
DFCLS
DFBLK
A/DF
N/A
R/W
R/W
R/W
R/W
R/W
R/W
R/W
0x3f
0x40… 0x53
0x54
AuthenticateCheckSum( )/BlockData( )
ACKS/DFD
(1) SEALED and UNSEALED states are entered via commands to CNTL 0x00/0x01.
(2) In sealed mode, data flash CANNOT be accessed through commands 0x3e and 0x3f.
14
GENERAL DESCRIPTION
Submit Documentation Feedback
Download from Www.Somanuals.com. All Manuals Search And Download.
bq27500
bq27501
System-Side Impedance Track™ Fuel Gauge
SLUS785–SEPTEMBER 2007
Table 4-5. Extended Data Commands (continued)
COMMAND
CODE
SEALED
UNSEALED
NAME
UNITS
ACCESS(1)(2)
ACCESS(1)(2)
BlockData( )
DFD
DFDCKS
DFDCNTL
DNAMELEN
DNAME
0x55… 0x5f
0x60
N/A
N/A
N/A
N/A
N/A
N/A
N/A
R
R/W
N/A
R
R/W
R/W
R/W
R
BlockDataCheckSum( )
BlockDataControl( )
DeviceNameLength( )
DeviceName( )
0x61
0x62
0x63...0x69
0x6a
R
R
ApplicationStatus( )
Reserved
APPSTAT
RSVD
R
R
0x6b...0x7f
R
R
4.1.2.1 DesignCapacity( ): 0x3c/0x3d
SEALED and UNSEALED Access: This command returns the theoretical or nominal capacity of a new
pack. The value is stored in Design Capacity and is expressed in mAh. This is intended to be the
theoretical or nominal capacity of a new pack, but has no bearing on the operation of the fuel gauge
functionality.
4.1.2.2 DataFlashClass( ): 0x3e
UNSEALED Access: This command sets the data flash class to be accessed. The class to be accessed
should be entered in hexadecimal.
SEALED Access: This command is not available in SEALED mode.
4.1.2.3 DataFlashBlock( ): 0x3f
UNSEALED Access: This command sets the data flash block to be accessed. When “0x00” is written to
BlockDataControl( ), DataFlashBlock( ) holds the block number of the data flash to be read or written.
Example: writing a 0x00 to DataFlashBlock( ) specifies access to the first 32 byte block and a 0x01
specifies access to the second 32 byte block, and so on.
SEALED Access: This command directs which data flash block will be accessed by the BlockData( )
command. Writing a 0x00 to DataFlashBlock( ) specifies the BlockData( ) command will transfer
authentication data. Issuing a 0x01, 0x02 or 0x03 instructs the BlockData( ) command to transfer
Manufacturer Info Block A, B, or C, respectively.
4.1.2.4 BlockData( ): 0x40… 0x5f
UNSEALED Access: This data block is the remainder of the 32 byte data block when accessing data
flash.
SEALED Access: This data block is the remainder of the 32 byte data block when accessing
Manufacturer Block Info A, B, or C.
4.1.2.5 BlockDataChecksum( ): 0x60
UNSEALED Access: This byte contains the checksum on the 32 bytes of block data read or written to
data flash. The least significant byte of the sum of the data bytes written must be complemented ( [255 –
x] , for x the least significant byte) before being written to 0x60.
SEALED Access: This byte contains the checksum for the 32 bytes of block data written to Manufacturer
Info Block A, B, or C. The least significant byte of the sum of the data bytes written must be
complemented ( [255 – x] , for x the least significant byte) before being written to 0x60.
4.1.2.6 BlockDataControl( ): 0x61
UNSEALED Access: This command is used to control data flash access mode. Writing 0x00 to this
command enables BlockData( ) to access general data flash. Writing a 0x01 to this command enables
SEALED mode operation of DataFlashBlock( ).
SEALED Access: This command is not available in SEALED mode.
Submit Documentation Feedback
GENERAL DESCRIPTION
15
Download from Www.Somanuals.com. All Manuals Search And Download.
bq27500
bq27501
System-Side Impedance Track™ Fuel Gauge
SLUS785–SEPTEMBER 2007
4.1.2.7 DeviceNameLength( ): 0x62
UNSEALED and SEALED Access: This byte contains the length of the Device Name.
4.1.2.8 DeviceName( ): 0x63… 0x69
UNSEALED and SEALED Access: This block contains the device name that is programmed in Device
Name.
4.1.2.9 ApplicationStatus( ): 0x6a
This byte function allows the system to read the Application Status register of the bq27500/01. See
4.1.2.10 Reserved – 0x6b – 0x7f
4.2 DATA FLASH INTERFACE
4.2.1 ACCESSING THE DATA FLASH
The bq27500/1 data flash is a non-volatile memory that contains bq27500/1 initialization, default, cell
status, calibration, configuration, and user information. The data flash can be accessed in several different
ways, depending on what mode the bq27500/1 is operating in and what data is being accessed.
Commonly accessed data flash memory locations, frequently read by a system, are conveniently
commands are available when the bq27500/1 is either in UNSEALED or SEALED modes.
Most data flash locations, however, are only accessible in UNSEALED mode by use of the bq27500/1
evaluation software or by data flash block transfers. These locations should be optimized and/or fixed
during the development and manufacture processes. They become part of a golden image file and can
then be written to multiple battery packs. Once established, the values generally remain unchanged during
end-equipment operation.
To access data flash locations individually, the block containing the desired data flash location(s) must be
transferred to the command register locations, where they can be read to the system or changed directly.
This is accomplished by sending the set-up command BlockDataControl( ) (0x61) with data 0x00. Up to 32
bytes of data can be read directly from the BlockData( ) (0x40… 0x5f), externally altered, then re-written to
the BlockData( ) command space. Alternatively, specific locations can be read, altered, and re-written if
their corresponding offsets are used to index into the BlockData( ) command space. Finally, the data
residing in the command space is transferred to data flash, once the correct checksum for the whole block
is written to BlockDataChecksum( ) (0x60).
Occasionally, a data flash CLASS will be larger than the 32-byte block size. In this case, the
DataFlashBlock( ) command is used to designate in which 32-byte block the desired locations resides.
The correct command address is then given by 0x40 + offset modulo 32. For example, to access
Terminate Voltage in the Gas Gauging class, DataFlashClass( ) is issued 80 (0x50) to set the class.
Because the offset is 48, it must reside in the second 32-byte block. Hence, DataFlashBlock( ) is issued
0x01 to set the block offset, and the offset used to index into the BlockData( ) memory area is 0x40 + 48
modulo 32 = 0x40 + 16 = 0x40 + 0x10 = 0x50.
Reading and writing subclass data are block operations up to 32 bytes in length. If during a write the data
length exceeds the maximum block size, then the data is ignored.
None of the data written to memory are bounded by the bq27500/1– the values are not rejected by the
fuel gauge. Writing an incorrect value may result in hardware failure due to firmware program
interpretation of the invalid data. The written data is persistent, so a Power-On-Reset does resolve the
fault.
16
GENERAL DESCRIPTION
Submit Documentation Feedback
Download from Www.Somanuals.com. All Manuals Search And Download.
bq27500
bq27501
System-Side Impedance Track™ Fuel Gauge
SLUS785–SEPTEMBER 2007
4.3 MANUFACTURER INFORMATION BLOCKS
The bq27350 contains 96 bytes of user programmable data flash storage: Manufacturer Info Block A,
Manufacturer Info Block B, Manufacturer Info Block C. The method for accessing these memory
locations is slightly different, depending on whether the device is in UNSEALED or SEALED modes.
When in UNSEALED mode and when and “0x00” has been written to BlockDataControl( ), accessing the
Manufacturer Info Blocks is identical to accessing general data flash locations. First, a DataFlashClass( )
command is used to set the subclass, then a DataFlashBlock( ) command sets the offset for the first data
flash address within the subclass. The BlockData( ) command codes contain the referenced data flash
data. When writing the data flash, a checksum is expected to be received by BlockDataChecksum( ). Only
when the checksum is received and verified is the data actually written to data flash.
As an example, the data flash location for Manufacturer Info Block B is defined as having a Subclass =
58 and an Offset = 32 through 63 (32 byte block). The specification of Class = System Data is not needed
to address Manufacturer Info Block B, but is used instead for grouping purposes when viewing data
flash info in the bq27500/1 evaluation software.
When in SEALED mode or when “0x01” BlockDataControl( ) does not contain “0x00”, data flash is no
longer available in the manner used in UNSEALED mode. Rather than issuing subclass information, a
designated Manufacturer Information Block is selected with the DataFlashBlock( ) command. Issuing a
0x01, 0x02, or 0x03 with this command causes the corresponding information block (A, B, or C,
respectively) to be transferred to the command space 0x40… 0x5f for editing or reading by the system.
Upon successful writing of checksum information to BlockDataChecksum( ), the modified block is returned
to data flash. Note: Manufacturer Info Block A is “read only” when in SEALED mode.
4.4 ACCESS MODES
The bq27500/1 provides three security modes in which control data flash access permissions according to
Table 4-6. Public Access refers to those data flash locations, specified in Table 4-7, that are accessible to
the user. Private Access refers to reserved data flash locations used by the bq27500/1 system. Care
should be taken to avoid writing to Private data flash locations when performing block writes in FULL
Table 4-6. Data Flash Access
Security Mode
BOOTROM
FULL ACCESS
UNSEALED
SEALED
DF – Public Access
DF – Private Access
N/A
R/W
R/W
R
N/A
R/W
R/W
N/A
Although FULL ACCESS and UNSEALED modes appear identical, FULL ACCESS allows the bq27500/1
to directly transition to BOOTROM mode and also write access mode transition keys. The UNSEAL mode
lacks these abilities.
4.5 SEALING/UNSEALING DATA FLASH
The bq27500/1 implements a key-access scheme to transition between SEALED, UNSEALED, and
FULL-ACCESS modes. Each transition requires that a unique set of 2 keys be sent to the bq27500/1 via
the Control( ) control command. The keys must be sent consecutively, with no other data being written to
the Control( ) register in between. Note that to avoid conflict, the keys must be different from the codes
When in SEALED mode the Control Status( )’s [SS] bit is set, but when the UNSEAL keys are correctly
received by the bq27500/1, the [SS] bit is cleared. When the FULL-ACCESS keys are correctly received
then the Control Status( ) [FAS] bit is cleared.
Submit Documentation Feedback
GENERAL DESCRIPTION
17
Download from Www.Somanuals.com. All Manuals Search And Download.
bq27500
bq27501
System-Side Impedance Track™ Fuel Gauge
SLUS785–SEPTEMBER 2007
Both the sets of keys for each level are 2 bytes each in length and are stored in data flash. The UNSEAL
key (stored at Unseal Key 0 and Unseal Key 1) and the FULL-ACCESS key (stored at Full Access Key
0 and Full Access Key 1) can only be updated when in FULL-ACCESS mode. The order of the bytes
entered through the Control( ) command is the reverse of what is read from the part. For example, if the
1st and 2nd word of Unseal Key 0 read returns 0x1234 and 0x5678, then the Control( ) should supply
0x3412 and 0x7856 to unseal the part.
4.6 DATA FLASH SUMMARY
Table 4-7 summarizes the data flash locations available to the user, including their default, minimum, and
maximum values.
Table 4-7. Data Flash Summary
Subclass
ID
Data
Type
Min
Value
Max
Value
Default
Value
Class
Subclass
Offset
Name
Units
Configuration
Configuration
Configuration
Configuration
Configuration
Configuration
2
2
2
2
2
2
Safety
Safety
Safety
Safety
Safety
Safety
0
2
3
5
7
8
OT Chg
I2
U1
I2
0
0
0
0
0
0
1200
60
550
2
0.1°C
s
OT Chg Time
OT Chg Recovery
OT Dsg
1200
1200
60
500
600
2
0.1°C
0.1°C
s
I2
OT Dsg Time
OT Dsg Recovery
U1
I2
1200
550
0.1°C
Charge Inhibit
Config
Configuration
Configuration
Configuration
32
32
32
0
2
4
Charge Inhibit Temp Low
Charge Inhibit Temp High
Temp Hys
12
12
12
–400
–400
0
1200
1200
100
0
0.1°C
0.1°C
0.1°C
Charge Inhibit
Config
450
50
Charge Inhibit
Config
Configuration
Configuration
Configuration
Configuration
34
34
34
34
Charge
Charge
Charge
Charge
2
4
6
8
Charging Voltage
I2
I2
I2
I2
0
20000
500
4200
50
mV
Delta Temperature
0
0.1°C
0.1°C
0.1°C
Suspend Temperature Low
Suspend Temperature High
–400
–400
1200
1200
–50
550
Charge
Termination
Configuration
Configuration
Configuration
Configuration
36
36
36
36
2
4
6
8
Taper Current
I2
I2
0
0
0
0
1000
1000
1000
60
100
64
mA
mAh
mV
s
Charge
Termination
Minimum Taper Charge
Taper Voltage
Charge
Termination
I2
100
40
Charge
Termination
Current Taper Window
U1
Configuration
Configuration
Configuration
Configuration
Configuration
48
48
48
48
48
Data
Data
Data
Data
Data
0
6
SOC1 Set
I2
I1
I2
I2
I2
0
–256
–32767
100
700
0
100
–10
mAh
mA
Initial Standby Current
Initial Max Load Current
CC Threshold
7
0
–1000
1400
1500
mA
9
32767
65535
mAh
mAh
12
Design Capacity
0
bq27500
or
Configuration
48
Data
39
Device Name
S8
x
x
–
bq27501
Configuration
Configuration
Configuration
49
49
49
Discharge
Discharge
Discharge
0
2
4
SOCF Set %
I1
I1
I1
–1
–1
0
100
100
100
6
8
%
%
%
SOCF Clear %
Max Load RSOC
50
Manufacturer
Info
System Data
System Data
System Data
58
58
58
0–31
32–63
64–95
Block A [0–31]
Block B [0–31]
Block C [0–31]
H1
H1
H1
0x00
0x00
0x00
0xff
0xff
0xff
0x00
0x00
0x00
–
–
–
Manufacturer
Info
Manufacturer
Info
18
GENERAL DESCRIPTION
Submit Documentation Feedback
Download from Www.Somanuals.com. All Manuals Search And Download.
bq27500
bq27501
System-Side Impedance Track™ Fuel Gauge
SLUS785–SEPTEMBER 2007
Table 4-7. Data Flash Summary (continued)
Subclass
ID
Data
Type
Min
Value
Max
Value
Default
Value
Class
Subclass
Offset
Name
Units
Configuration
Configuration
Configuration
Configuration
64
64
64
64
Registers
Registers
Registers
Registers
0
2
4
8
Operation Configuration
Pack 0 Voltage(1)
Pack 1 Voltage(1)
H2
U2
U2
U1
0x0000
0xffff
4200
4200
100
0x0979
1000
4000
5
–
0
0
0
mV
mV
%
Pack V% Range(1)
Configuration
Configuration
Configuration
Configuration
68
68
68
68
Power
Power
Power
Power
0
7
Flash Update OK Voltage
Sleep Current
I2
I2
0
0
4200
100
2800
10
mV
mA
16
18
Bat Low Threshold
I2
0
700
100
2550
mAh
mV
Hibernate Voltage Threshold
U2
2400
3000
Gas Gauging
Gas Gauging
Gas Gauging
Gas Gauging
Gas Gauging
Gas Gauging
Gas Gauging
80
80
80
80
80
80
80
IT Cfg
IT Cfg
IT Cfg
IT Cfg
IT Cfg
IT Cfg
IT Cfg
0
Load Select
U1
U1
I2
0
255
255
1
–
–
1
Load Mode
0
0
48
53
55
57
59
Terminate Voltage
User Rate-mA
User Rate-mW
Reserve Cap-mAh
Reserve Cap-mWh
–32768
32767
9000
14000
9000
14000
3000
mV
I2
0
0
0
0
0
0
0
0
mA
I2
10mW
mAh
10mWh
I2
I2
Current
Thresholds
Gas Gauging
Gas Gauging
Gas Gauging
Gas Gauging
Gas Gauging
Gas Gauging
81
81
81
81
81
81
0
2
4
6
8
9
Dsg Current Threshold
Chg Current Threshold
Quit Current
I2
I2
0
0
0
0
0
0
2000
2000
1000
8191
255
75
75
mA
mA
mA
s
Current
Thresholds
Current
Thresholds
I2
50
Current
Thresholds
Dsg Relax Time
U2
U1
U1
1800
60
Current
Thresholds
Chg Relax Time
Quit Relax Time
s
Current
Thresholds
63
1
s
Gas Gauging
Gas Gauging
Gas Gauging
Gas Gauging
Gas Gauging
Gas Gauging
Gas Gauging
Gas Gauging
Gas Gauging
Gas Gauging
82
82
82
82
82
82
82
82
82
82
State
State
State
State
State
State
State
State
State
State
0
1
IT Enable
H1
H1
I2
0x00
0x00
0
0xff
0x00
0x00
1500
0
–
–
Application Status
Qmax 0
0xff
2
32767
65535
0x03
mAh
–
4
Cycle Count 0
Update Status 0
Qmax 1
U2
H1
I2
0
6
0x00
0
0x00
1500
0
–
7
32767
65535
0x03
mAh
–
9
Cycle Count 1
Update Status 1
Avg I Last Run
Avg P Last Run
U2
H1
I2
0
11
16
18
0x00
–32768
–32768
0x00
300
1200
–
32767
32767
mA
mAh
I2
OCVTables
OCVTables
OCVTables
OCVTables
83
84
85
86
OCVa0 Table
OCVa1Table
OCVb0 Table
OCVb1 Table
0-45
0-45
0-64
0-64
See Note(2)
Default Ra Tables
Default Ra Tables
87
88
Def0 Ra
Def1 Ra
0-18
0-18
See Note(2)
See Note(2)
Rb Tables
Rb Tables
89
90
Rb0 Table
Rb1 Table
0-18
0-18
(1) bq27501 only.
(2) Encoded battery profile information created by bqEASY software.
Submit Documentation Feedback
GENERAL DESCRIPTION
19
Download from Www.Somanuals.com. All Manuals Search And Download.
bq27500
bq27501
System-Side Impedance Track™ Fuel Gauge
SLUS785–SEPTEMBER 2007
Table 4-7. Data Flash Summary (continued)
Subclass
ID
Data
Type
Min
Value
Max
Value
Default
Value
Class
Subclass
Offset
Name
Units
Ra Tables
Ra Tables
Ra Tables
Ra Tables
91
92
93
94
Pack0 Ra
Pack1 Ra
Pack0 Rax
Pack1 Rax
0-18
0-18
0-18
0-18
See Note(2)
Calibration
Calibration
Calibration
Calibration
Calibration
Calibration
Calibration
104
104
104
104
104
104
104
Data
Data
Data
Data
Data
Data
Data
0
4
CC Gain
CC Delta
CC Offset
F4
F4
I2
0.1
29826
-32768
–128
–128
–128
–128
4
1193046
32767
127
0.47095
mΩ
mΩ
280932.6
8
–1667
mV
10
11
12
13
Board Offset
I1
0
0
0
0
mV
Int Temp Offset
Ext Temp Offset
Pack V Offset
I1
127
0.1°C
0.1°C
0.1°C
I1
127
I1
127
Calibration
107
Current
1
Deadband
U1
0
255
3
mA
Security
Security
Security
Security
112
112
112
112
Codes
Codes
Codes
Codes
0
2
4
6
Usealed Key0
H2
H2
H2
H2
0x0000
0x0000
0x0000
0x0000
0xffff
0xffff
0xffff
0xffff
–
–
–
–
–
–
–
–
Usealed Key1
Full-Access Key0
Full-Access Key1
5 FUNCTIONAL DESCRIPTION
5.1 FUEL GAUGING
The bq27500/1 measures the cell voltage, temperature, and current to determine battery SOC. The
bq27500/1 monitors charge and discharge activity by sensing the voltage across a small-value resistor
(5mΩ to 20 mΩ typ.) between the SRP and SRN pins and in series with the cell. By integrating charge
passing through the battery, the cell’s SOC is adjusted during battery charge or discharge.
The total battery capacity is found by comparing states of charge before and after applying the load with
the amount of charge passed. When an application load is applied, the impedance of the cell is measured
by comparing the OCV obtained from a predefined function for present SOC with the measured voltage
under load. Measurements of OCV and charge integration determine chemical state of charge and
Chemical Capacity (Qmax). The initial Qmax values are taken from a cell manufacturers' data sheet
multiplied by the number of parallel cells. It is also used for the value in Design Capacity. The bq27500/1
acquires and updates the battery-impedance profile during normal battery usage. It uses this profile, along
with SOC and the Qmax value, to determine FullChargeCapacity( ) and StateOfCharge( ), specifically for
the present load and temperature. FullChargeCapacity( ) is reported as capacity available from a fully
charged battery under the present load and temperature until Voltage( ) reaches the Term Voltage.
NominalAvailableCapacity( ) and FullAvailableCapacity( ) are the uncompensated (no or light load)
versions of RemainingCapacity( ) and FullChargeCapacity( ) respectively.
The bq27500/1 has two flags accessed by the Flags( ) function that warns when the cell’s SOC has fallen
to critical levels. When RemainingCapacity( ) falls below the first capacity threshold, specified in SOC1
Set, the [SOC1] (“State of Charge Initial””) flag is set. The flag is cleared, once RemainingCapacity( ) rises
above SOC1 Set. All units are in mAh.
When RemainingCapacity( ) falls below the second capacity threshold, SOCF Set, the [SOCF] (“State of
Charge Final”) flag is set, serving as a final discharge warning. If SOCF Set = –1, the flag is inoperative
during discharge.
Similarly, when RemainingCapacity( ) rises above SOCF Clear and the [SOCF] flag has already been set,
the [SOCF] flag will be cleared, provided SOCF Set ≠ –1. All units are in mAh.
20
FUNCTIONAL DESCRIPTION
Submit Documentation Feedback
Download from Www.Somanuals.com. All Manuals Search And Download.
bq27500
bq27501
System-Side Impedance Track™ Fuel Gauge
SLUS785–SEPTEMBER 2007
5.2 IMPEDANCE TRACK™ VARIABLES
The bq27500/1 has several data flash variables that permit the user to customize the Impedance Track™
algorithm for optimized performance. These variables are dependent upon the power characteristics of the
application as well as the cell itself.
Load Mode
Load Mode is used to select either the constant current or constant power model for the Impedance Track™ algorithm as used in
Load Select (see Load Select). When Load Mode is 0, the Constant Current Model is used (default). When 1, the Constant
Power Model is used. The [LDMD] bit of CONTROL STATUS reflects the status of Load Mode.
Load Select
Load Select defines the type of power or current model to be used to compute load-compensated capacity in the Impedance
Track™ algorithm. If Load Mode = 0 (Constant Current) then the options presented in Table 5-1 are available.
Table 5-1. Constant-Current Model Used When Load Mode = 0
LoadSelect Value
Current Model Used
Average discharge current from previous cycle: There is an internal register that records the average discharge
current through each entire discharge cycle. The previous average is stored in this register.
0
Present average discharge current: This is the average discharge current from the beginning of this discharge
cycle until present time.
1(default)
2
3
4
5
6
Average Current: based on AverageCurrent( )
Current: based off of a low-pass-filtered version of AverageCurrent( ) (τ =14s)
Design Capacity / 5: C Rate based off of Design Capacity /5 or a C/5 rate in mA.
AtRate (mA): Use whatever current is in AtRate( )
User_Rate-mA: Use the value in User_Rate( ). This gives a completely user configurable method.
Table 5-2. Constant-Power Model Used When Load Mode = 1
LoadSelect Value
Power Model Used
Average discharge power from previous cycle: There is an internal register that records the average discharge
power through each entire discharge cycle. The previous average is stored in this register.
0
Present average discharge power: This is the average discharge power from the beginning of this discharge cycle
until present time.
1(default)
2
3
4
5
6
Average Current×Voltage: based off the AverageCurrent( ) and Voltage( ).
Current ×Voltage: based off of a low-pass-filtered version of AverageCurrent( ) (τ=14s) and Voltage( )
Design Energy / 5: C Rate based off of Design Energy /5 or a C/5 rate in mA.
AtRate (10 mW): Use whatever value is in AtRate( ).
User_Rate-10mW: Use the value in User_Rate( ) mW. This gives a completely user configurable method.
Reserve Cap-mAh
Reserve Cap-mAh determines how much actual remaining capacity exists after reaching 0 RemainingCapacity( ), before
Terminate Voltage is reached. A no-load rate of compensation is applied to this reserve.
Reserve Cap-mWh
Reserve Cap-mWh determines how much actual remaining capacity exists after reaching 0 AvailableEnergy( ), before
Terminate Voltage is reached. A no-load rate of compensation is applied to this reserve capacity.
Submit Documentation Feedback
FUNCTIONAL DESCRIPTION
21
Download from Www.Somanuals.com. All Manuals Search And Download.
bq27500
bq27501
System-Side Impedance Track™ Fuel Gauge
SLUS785–SEPTEMBER 2007
Dsg Current Threshold
This register is used as a threshold by many functions in the bq27350 to determine if actual discharge current is flowing into or
out of the cell. The default for this register is 100mA which should be sufficient for most applications. This threshold should be
set low enough to be below any normal application load current but high enough to prevent noise or drift from affecting the
measurement.
Chg Current Threshold
This register is used as a threshold by many functions in the bq27500/1 to determine if actual charge current is flowing into or
out of the cell. The default for this register is 50mA which should be sufficient for most applications. This threshold should be set
low enough to be below any normal charge current but high enough to prevent noise or drift from affecting the measurement.
Quit Current, Dsg Relax Time, Chg Relax Time, and Quit Relax Time
The Quit Current is used as part of the Impedance Track™ algorithm to determine when the bq27500 enters relaxation mode
from a current flowing mode in either the charge direction or the discharge direction. The value of Quit Current is set to a default
value of 10mA and should be above the standby current of the system.
Either of the following criteria must be met to enter relaxation mode:
1. | AverageCurrent( ) | < | Quit Current | for Dsg Relax Time.
2. | AverageCurrent( ) | < | Quit Current | for Chg Relax Time.
After about 30 minutes in relaxation mode, the bq27500 attempts to take accurate OCV readings. An additional requirement of
dV/dt < 4 μV/sec is required for the bq27500/1 to perform Qmax updates. These updates are used in the Impedance Track™
algorithms. It is critical that the battery voltage be relaxed during OCV readings to and that the current is not be higher than C/20
when attempting to go into relaxation mode.
Quit Relax Time specifies the minimum time required for AverageCurrent( ) to remain above the QuitCurrent threshold before
exiting relaxation mode.
Qmax 0 and Qmax 1
Generically called Qmax, these dynamic variables contain the respective maximum chemical capacity of the active cell profiles,
and are determined by comparing states of charge before and after applying the load with the amount of charge passed. They
also correspond to capacity at very low rate of discharge, such as C/20 rate. For high accuracy, this value is periodically
updated by the bq27500/1 during operation. Based on the battery cell capacity information, the initial value of chemical capacity
should be entered in the Qmax n field for each default cell profile. The Impedance Track™ algorithm will update these values
and maintain them the associated actual cell profiles.
Update Status 0 and Update Status 1
Bit 1 (0x02) of the Update Status n registers indicates that the bq27500/1 has learned new Qmax parameters and is accurate.
The remaining bits are reserved. Bits 1 is user-configurable; however, it is also a status flag that can be set by the bq27500/1.
Bit 1 should never be modified except when creating a golden image file as explained in the application note “Preparing
Optimized Default Flash Constants for specific Battery Types” (see SLUA334.pdf). Bit 1 is updated as needed by the bq27500/1.
Avg I Last Run
The bq27500 logs the current averaged from the beginning to the end of each discharge cycle. It stores this average current
from the previous discharge cycle in this register. This register should never need to be modified. It is only updated by the
bq27500/1 when required.
Avg P Last Run
The bq27500/1 logs the power averaged from the beginning to the end of each discharge cycle. It stores this average power
from the previous discharge cycle in this register. To get a correct average power reading the bq27500/1 continuously multiplies
instantaneous current times Voltage( ) to get power. It then logs this data to derive the average power. This register should
never need to be modified. It is only updated by the bq27500/1 when required.
Delta Voltage
The bq27500/1 stores the maximum difference of Voltage( ) during short load spikes and normal load, so the Impedance
Track™ algorithm can calculate remaining capacity for pulsed loads. It is not recommended to change this value.
OCV, Default Ra, Rb, and Ra Tables
These tables contain encoded data and, with the exception of the Default Ra Tables, are automatically updated during device
operation. No user changes should be made except for reading/writing the values from a pre-learned pack (part of the process
for creating golden image files).
22
FUNCTIONAL DESCRIPTION
Submit Documentation Feedback
Download from Www.Somanuals.com. All Manuals Search And Download.
bq27500
bq27501
System-Side Impedance Track™ Fuel Gauge
SLUS785–SEPTEMBER 2007
5.3 DETAILED DESCRIPTION OF DEDICATED PINS
5.3.1 The Operation Configuration Register
Some bq27500/1 pins are configured via the Operation Configuration data flash register, as indicated in
Table 5-3. This register is programmed/read via the methods desribed in Section 4.2.1 Accessing the Data
Flash. The register is located at subclass = 64, offset = 0.
Table 5-3. Operation Configuration Bit Definition
Operation
Cfg
bit7
bit6
bit5
bit4
bit3
bit2
bit1
bit0
High Byte
Low Byte
RESCAP
–
–
–
PFC_CFG1
RMFCC
PFC_CFG0
BATL_POL
IWAKE
RSNS1
–
RSNS0
TEMPS
IDSELEN
SLEEP
BATG_POL
RESCAP = No-load rate of compensation is applied to the reserve capacity calculation. True when set. Default is 0.
PFC_CFG1/PFC_CFG0 = Pin Function Code (PFC) mode selection: PFC 0, 1, or 2 selected by 0/0, 0/1, or 1/0, respectively. Default is PFC
1 (0/1).
IWAKE/RSNS1/RSNS0 = These bits configure the current wake function (ref. Table 5-3). Default is 0/0/1.
IDSELEN = Enables cell profile selection feature. True when set. Default is 1.
SLEEP = The fuel gauge can enter sleep, if operating conditions allow. True when set. Default is 1.
RMFCC = RM is updated with the value from FCC, on valid charge termination. True when set. Default is 1.
BATL_POL = BAT_LOW pin is active-high. True when set. Default is 1.
BATG_POL = BAT_GD pin is active-low. True when cleared. Default is 0.
TEMPS = Selects external thermistor for Temperature( ) measurements. True when set. Default is 1.
5.3.2 Pin Function Code Descriptions
The bq27500/1 has three possible pin-function variations that can be selected in accordance with the
circuit architecture of the end application. Each variation has been assigned a Pin Function Code, or PFC.
When the PFC is set to 0, only the bq27500/1 measures battery temperature under discharge and
relaxation conditions. The charger does not receive any information from the bq27500/1 about the
temperature readings, and therefore operates open-loop with respect to battery temperature.
A PFC of 1 is like a PFC of 0, except temperature is also monitored during battery charging. If charging
temperature falls outside of the preset range defined in data flash,a charger can be disabled via the
BAT_GD pin, until cell temperature recovers. See Section 5.6.2 Charge Inhibit for additional details.
Finally when the PFC is set to 2, the battery thermistor can be shared between the fuel gauge and the
charger. The charger has full usage of the thermistor during battery charging, while the fuel gauge uses
the thermistor exclusively during discharge and battery relaxation.
The PFC is specified in Operation Configuration [PFC_CFG1, PFC_CFG0]. The default is PFC = 1.
5.3.3 BAT_LOW Pin
The BAT_LOW pin provides a system processor with an electrical indicator of battery status. The signaling
on the BAT_LOW pin follows the status of the [SOC1] bit in the Flags( ) register. Note that the polarity of
the BAT_LOW pin can be inverted via the [BATL_POL] bit of Operation Configuration.
5.3.4 Power Path Control with the BAT_GD Pin
The bq27500/1 must operate in conjunction with other electronics in a system appliance, such as chargers
and other IC’s and subcircuits that draw appreciable power. After a battery is inserted into the system, this
electronics must be disabled, so that an accurate OCV can be read. The OCV is used for helping
determine which battery profile to use, as it constitutes part of the battery impedance measurement.
When a battery is inserted into a system, the Impedance Track™ algorithm requires that no charging of
the battery takes place and that any discharge is limited to less than C/20—these conditions are sufficient
Submit Documentation Feedback
FUNCTIONAL DESCRIPTION
23
Download from Www.Somanuals.com. All Manuals Search And Download.
bq27500
bq27501
System-Side Impedance Track™ Fuel Gauge
SLUS785–SEPTEMBER 2007
for the fuel gauge to take an accurate OCV reading. To disable these functions, the BAT_GD pin is merely
set high (floating output pulled high). Once an OCV reading has be made, the BAT_GD pin is pulled low,
thereby enabling battery charging and regular discharge of the battery. The Operation Configuration
[BATG_POL] bit can be used to set the polarity of the battery good signal, should the default configuration
need to be changed.
The flowchart of Figure 5-1 details how the BAT_GD pin functions in the context of battery insertion and
removal, as well as NORMAL vs SLEEP modes.
In PFC 1, the BAT_GD pin is also used to disable battery charging when the bq27500/1 reads battery
temperatures outside the range defined by [Charge Inhibit Temp Low, Charge Inhibit Temp High]. The
BAT_GD line is returned to low once temperature falls within the range [Charge Inhibit Temp Low +
Temp Hys, Charge Inhibit Temp High – Temp Hys].
5.3.5 Battery Detection Using the BI/TOUT Pin
During power-up or HIBERNATE activities, or any other activity where the bq27500/1 needs to determine
whether a battery is connected or not, the fuel gauge applies a test for battery presence. First, the
BI/TOUT pin is put into high-Z status. The weak 1.8MΩ pull-up resistor will keep the pin high while no
battery is present. When a battery is inserted (or is already inserted) into the system device, the BI/TOUT
pin will be pulled low. This state is detected by the fuel gauge, which polls this pin every second when the
gauge has power. A battery disconnected status is assumed when the bq27500/1 reads a thermistor
voltage that is near 2.5V.
24
FUNCTIONAL DESCRIPTION
Submit Documentation Feedback
Download from Www.Somanuals.com. All Manuals Search And Download.
bq27500
bq27501
System-Side Impedance Track™ Fuel Gauge
SLUS785–SEPTEMBER 2007
Start
Bq27500 POR
No
Batt
detected?
Yes
Init
(“BAT_GD”
disabled, OCV
taken, “BAT_GD
enabled.)
Battery Volt
Sufficient
to FG?
No
Yes
NORMAL
SLEEP
Batt Present
IT Operations
(dsg, chg, rlx)
Icc >
Istandby -OR-
Yes
T > 30min
r
Yes
No
Bad batt
detected?
No
Batt
removed?
No
Yes
Yes
Batt
removed?
No Batt Present
-OR- bad batt
(“BAT_GD”
No
disabled)
Forced
SLEEP
Mode?
Yes
No
Batt
detected?
Yes
Bad batt
detected?
No
Yes
No
AC or USB
Present?
Yes
No
End
Figure 5-1. BAT_GD Pin Operation, Based Upon Battery Presence and bq27500 Operating Mode
Submit Documentation Feedback
FUNCTIONAL DESCRIPTION
25
Download from Www.Somanuals.com. All Manuals Search And Download.
bq27500
bq27501
System-Side Impedance Track™ Fuel Gauge
SLUS785–SEPTEMBER 2007
5.4 TEMPERATURE MEASUREMENT
The bq27500/1 measures battery temperature via its TS input, in order to supply battery temperature
status information to Impedance Track™ and charger control sections of the gauge. Alternatively, it can
also measure internal temperature via its on-chip temperature sensor, but only if the [TEMPS] bit of
Operation Configuration register is cleared.
Regardless of which sensor is used for measurement, a system processor can request the current battery
specific information).
The recommended thermistor circuit uses an external 103AT-type thermistor. Additional circuit information
5.5 OVERTEMPERATURE INDICATION
5.5.1 Overtemperature: Charge
If during charging, Temperature( ) reaches the threshold of OT Chg for a period of OT Chg Time and
AverageCurrent( ) > Chg Current Threshold, then the [OTC] bit of Flags( ) is set. Note: if OT Chg Time =
0 then feature is completely disabled.
When Temperature( ) falls to OT Chg Recovery, the [OTC] of Flags( ) is reset.
5.5.2 Overtemperature: Discharge
If during discharging, Temperature( ) reaches the threshold of OT Dsg for a period of OT Dsg Time, and
AverageCurrent( ) ≤ -Dsg Current Threshold, then the [OTD] bit of Flags( ) is set. Note: if OT Dsg Time
= 0, then feature is completely disabled.
When Temperature( ) falls to OT Dsg Recovery, the [OTD] bit of Flags( ) is reset.
5.6 CHARGING AND CHARGE-TERMINATION INDICATION
5.6.1 Detecting Charge Termination
For proper bq27500/1 operation, the cell charging voltage must be specified by the user. The default value
for this variable is Charging Voltage = 4200mV.
The bq27500/1 detects charge termination when (1) during 2 consecutive periods of Current Taper
Window, the AverageCurrent( ) is < Taper Current and (2) during the same periods, the accumulated
change in capacity > 0.25mAh /Current Taper Window and (3) Voltage( ) > Charging Voltage – Taper
Voltage. When this occurs, the [CHG] bit of Flags( ) is cleared. Also, if the [RMFCC] bit of Operation
Configuration is set, and RemainingCapacity( ) is set equal to FullChargeCapacity( ).
5.6.2 Charge Inhibit
When PFC = 1, the bq27500/1 can indicate when battery temperature has fallen below or risen above
predefined thresholds (Charge Inhibit Temp Low and Charge Inhibit Temp High, respectively). In this
mode, the BAT_GD line is made high to indicate this condition, and is returned to its low state, once
battery temperature returns to the range [Charge Inhibit Temp Low + Temp Hys, Charge Inhibit Temp
High – Temp Hys].
When PFC = 0 or 2, the bq27500/1 must be queried by the system in order to determine the battery
temperature. At that time, the bq27500/1 will sample the temperature. This saves battery energy when
operating from battery, as periodic temperature updates are avoided during charging mode.
26
FUNCTIONAL DESCRIPTION
Submit Documentation Feedback
Download from Www.Somanuals.com. All Manuals Search And Download.
bq27500
bq27501
System-Side Impedance Track™ Fuel Gauge
SLUS785–SEPTEMBER 2007
5.7 POWER MODES
The bq27500/1 has four power modes: NORMAL, SLEEP, HIBERNATE, and BAT INSERT CHECK. In
NORMAL mode, the bq27500/1 is fully powered and can execute any allowable task. In SLEEP mode, the
fuel gauge exists in a reduced-power state, periodically taking measurements and performing calculations.
In HIBERNATE mode, the fuel gauge is in its lowest power state, but can be woken up by communication
activity or certain I/O activity. Finally, the BAT INSERT CHECK mode is a powered-up, but low-power
halted, state, where the bq27500/1 resides when no battery is inserted into the system.
5.7.1 NORMAL MODE
The fuel gauge is in NORMAL Mode when not in any other power mode. During this mode,
AverageCurrent( ), Voltage( ) and Temperature( ) measurements are taken, and the interface data set is
updated. Decisions to change states are also made. This mode is exited by activating a different power
mode.
Because the gauge consumes the most power in NORMAL mode, the Impedance Track™ algorithm
minimizes the time the fuel gauge remains in this mode.
5.7.2 SLEEP MODE
SLEEP mode is entered automatically if the feature is enabled (Operation Configuration [SLEEP]) = 1)
and AverageCurrent( ) is below the programmable level Sleep Current. Once entry into SLEEP mode
has been qualified, but prior to entering it, the bq27500/1 performs an ADC autocalibration to minimize
offset.
During SLEEP mode, the bq27500/1 periodically takes data measurements and updates its data set.
However, a majority of its time is spent in an idle condition.
The bq27500/1 exits SLEEP if any entry condition is broken, specifically when (1) AverageCurrent( ) rises
above Sleep Current, or (2) a current in excess of IWAKE through RSENSE is detected.
In the event that a battery is removed from the system while a charger is present (and powering the
gauge), Impedance Track™ updates are not necessary. Hence, the fuel gauge enters a state that checks
for battery insertion and does not continue executing the Impedance Track™ algorithm.
5.7.3 BAT INSERT CHECK MODE
This mode is a halted-CPU state that occurs when an adapter, or other power source, is present to power
the bq27500/1 (and system), yet no battery has been detected. When battery insertion is detected, a
series of initialization activities begin, which include: OCV measurement, setting the BAT_GD pin, and
selecting the appropriate battery profiles.
Some commands, issued by a system processor, can be processed while the bq27500/1 is halted in this
mode. The gauge will wake up to process the command, then return to the halted state awaiting battery
insertion.
Submit Documentation Feedback
FUNCTIONAL DESCRIPTION
27
Download from Www.Somanuals.com. All Manuals Search And Download.
bq27500
bq27501
System-Side Impedance Track™ Fuel Gauge
SLUS785–SEPTEMBER 2007
POR
BAT INSERT CHECK
Check for battery insertion
.
from HALT state
No gauging
] =0
Flags [BAT_DET
ICC = Sleep
Exit From HIBERNATE
(Communication Activity
AND
Comm address is for bq27500/1)
OR
Battery Removed
Entry to NORMAL
Flags [ BAT_DET] =1
Exit FromNORMAL
Flags [ BAT_DET] =0
(Control Status
[ HIBERNATE] is set to.0
NORMAL
Fuel gauging and data
updated every1s,
HIBERNATE
Wakeup From HIBERNATE
Exit From SLEEP
Disable all bq8032
subcircuits except GPIO.
Set /BAD_GD to “high”
status
Communication Activity
AND
Comm address is NOT for bq27500/1
Flags [BAT_DET] =0
ICC = Normal
Exit From SLEEP
|AverageCurrent ( )| >Sleep Current
ICC = Hibernate
OR
Current is Detected above I
WAKE
Entry to SLEEP
Operation Configuration[SLEEP] =1
AND
|AverageCurrent( )| ≤ Sleep Current
SLEEP
Entry To HIBERNATE
Host has set Control Status
[HIBERNATE] =1
OR
Fuel gauging and data
updated every 60 seconds
V
< Hibernate Voltage
CELL
ICC = Sleep
Figure 5-2. Power Mode Diagram
5.7.4 HIBERNATE MODE
HIBERNATE mode should be used when the system equipment needs to enter a very low-power state,
and minimal gauge power consumption is required. This mode is ideal when a system equipment is set to
its own SLEEP, HIBERNATE, or SHUTDOWN modes.
To enter HIBERNATE mode, either the system must set the [HIBERNATE] bit of the CONTROL STATUS
register OR the cell voltage must fall below Hibernate Voltage. The gauge will remain in HIBERNATE
mode until the battery is removed, or the system issues a direct I2C command to the gauge. I2C
Communication that is not directed to the gauge will not wake the gauge.
It is important that BAT_GD be set to disable status (no battery charging/discharging). This prevents a
charger application from inadvertently charging the battery before an OCV reading can be taken. It is the
system’s responsibility to wake the bq27500/1 after it has gone into HIBERNATE mode. After waking, the
gauge can proceed with the initialization of the battery information (OCV, profile selection, etc.)
28
FUNCTIONAL DESCRIPTION
Submit Documentation Feedback
Download from Www.Somanuals.com. All Manuals Search And Download.
bq27500
bq27501
System-Side Impedance Track™ Fuel Gauge
SLUS785–SEPTEMBER 2007
5.8 POWER CONTROL
5.8.1 RESET FUNCTIONS
When the bq27500 detects software reset ([RESET] bit of Control( ) initiated), it determines the type of
reset and increments the corresponding counter. This information is accessible by issuing the command
Control( ) function with the RESET_DATA subcommand.
against the previously stored checksum. If the checksum values do not match, the RAM is reinitialized (a
Full Reset). The stored checksum is updated every time RAM is altered.
DEVICE RESET
Generate Active
RAM checksum
value
NO
Stored
checksum
Re-initialize all
RAM
Do the Checksum
Values Match?
YES
NORMAL
OPERATION
Active RAM
changed ?
NO
YES
Store
checksum
Generate New
checksum value
Figure 5-3. Partial Reset Flow Diagram
Submit Documentation Feedback
FUNCTIONAL DESCRIPTION
29
Download from Www.Somanuals.com. All Manuals Search And Download.
bq27500
bq27501
System-Side Impedance Track™ Fuel Gauge
SLUS785–SEPTEMBER 2007
5.8.2 WAKE-UP COMPARATOR
The wake up comparator is used to indicate a change in cell current while the bq27500/1 is in either
SLEEP or HIBERNATE modes. Operation Configuration uses bits [RSNS1-RSNS0] to set the sense
resistor selection. Operation Configuration also uses the [IWAKE] bit to select one of two possible
voltage threshold ranges for the given sense resistor selection. An internal interrupt is generated when the
threshold is breached in either charge or discharge directions. Setting both [RSNS1] and [RSNS0] to "0"
disables this feature.
Table 5-4. IWAKE Threshold Settings(1)
RSNS1
RSNS0
IWAKE
Vth(SRP-SRN)
Disabled
0
0
0
0
1
1
1
1
0
0
1
1
0
0
1
1
0
1
0
1
0
1
0
1
Disabled
1.25 mV or –1.25 mV
2.5 mV or –2.5 mV
2.5 mV or –2.5 mV
5 mV or –5 mV
5 mV or –5 mV
10 mV or –10 mV
(1) The actual resistance value vs. the setting of the sense resistor is not important just the actual voltage
threshold when calculating the configuration.
5.8.3 FLASH UPDATES
Data Flash can only be updated if Voltage( ) ≥ Flash Update OK Voltage. Flash programming current can
cause an increase in LDO dropout. The value of Flash Update OK Voltage should be selected such that
the bq27500/1 VCC voltage does not fall below its minimum of 2.4V during Flash write operations.
5.9 AUTOCALIBRATION
The bq27500 provides an autocalibration feature that measures the voltage offset error across SRP and
SRN as operating conditions change. It subtracts the resulting offset error from normal sense resistor
voltage, VSR, for maximum measurement accuracy.
Auto calibration of the ADC begins on entry to SLEEP mode, except if Temperature( ) is <= 5°C or
Temperature( ) >= 45°C.
The fuel gauge also performs a single offset when (1) the condition of AverageCurrent( ) ≤ 100mA and (2)
{voltage change since last offset calibration ≥ 256mV} or {temperature change since last offset calibration
is greater than 80°C for ≥ 60s}.
Capacity and current measurements will continue at the last measured rate during the offset calibration
when these measurements cannot be performed. If the battery voltage drops more than 32mV during the
offset calibration, the load current has likely increased considerably; hence, the offset calibration will be
aborted.
30
FUNCTIONAL DESCRIPTION
Submit Documentation Feedback
Download from Www.Somanuals.com. All Manuals Search And Download.
bq27500
bq27501
System-Side Impedance Track™ Fuel Gauge
SLUS785–SEPTEMBER 2007
6 APPLICATION-SPECIFIC INFORMATION
6.1 BATTERY PROFILE STORAGE AND SELECTION
6.1.1 General Profile Description
When a battery pack is removed from system equipment that implements the bq27500/01, the fuel gauge
will maintain some of the battery’s information in case it is re-inserted. This way, the Impedance Track™
algorithm has
a
means of recovering battery-status information, thereby, maintaining good
State-of-Charge (SOC) estimates.
Two default battery profiles are available to store battery information. They are used to provide the
Impedance Track™ algorithm with the default information on two possible battery types expected to be
used with the end-equipment. These default profiles can be used to support batteries of different
chemistry, same chemistry but different capacities, or same chemistry but different models. Default
profiles are programmed by the end-equipment manufacturer. Note that in the case of bq27500, only one
of the default profiles can be selected, and this selection cannot be changed during end-equipment
operation.
In addition to the default profiles, the bq27500/01 maintains two abbreviated profiles. These tables hold
dynamic battery data, and keep track of the status for up to two of the most recent batteries used. In most
cases the bq27500/01 can administrate information on two removable battery packs.
6.1.2 Activities Upon Pack Insertion
6.1.2.1 First OCV and Impedance Measurement
At power-up the BAT_GD pin is inactive, so that the system cannot obtain power from the battery (this
depends on actual implementation). In this state, the battery is put in an open-circuit condition. Next, the
bq27500/1 measures its first open-circuit voltage (OCV) via the BAT pin. From the OCV(SOC) table, the
SOC of the inserted battery is found. Then the BAT_GD pin is made active, and the impedance of the
inserted battery is calculated from the measured voltage and the load current: Z(SOC) = ( OCV(SOC) – V
) / I. This impedance is compared with the impedance of the dynamic profiles, Packn Ra, and default
profiles, Defn Ra, for the same SOC (the letter "n" depicts either a "0" or "1").
6.1.2.2 Reading Application Status
The Application Status data flash location contains cell profile status information, and can be read using
the ApplicationStatus( ) Extended Command (0x6a/0x6b). The bit configuration of this function/location is
Table 6.1.3. ApplicationStatus( ) bit Definitions.
Application
bit7
bit6
bit5
bit4
bit3
bit2
bit1
bit0
Configuration
Byte
—
—
—
—
—
—
UNSUPBAT LU_ PROF
UNSUPBAT = Flag indicating inserted battery is not supported in the current cell profiles. True when set. bq27501 only.
LU_PROF = Last profile used by gas gauge. Cell0 last used when cleared. Cell1 last used when set. Default is 0.
6.2 APPLICATION-SPECIFIC FLOW AND CONTROL
6.2.1 Simple Battery (bq27500 Only)
The bq27500 supports only one type of battery profile. This profile is stored in both the Def0 Ra and Def1
Ra profiles. When a battery pack is inserted for the first time, the default profile is copied into the Packn
Ra profiles. Then the Impedance Track™ algorithm begins gas gauging, regularly updating Packn Ra as
the battery is used.
When an existing pack is removed from the bq27500 and a different (or same) pack is inserted, cell
Submit Documentation Feedback
APPLICATION-SPECIFIC INFORMATION
31
Download from Www.Somanuals.com. All Manuals Search And Download.
bq27500
bq27501
System-Side Impedance Track™ Fuel Gauge
SLUS785–SEPTEMBER 2007
impedance is measured immediately after battery detection. The bq27500 chooses the profile which is
closest to the measured impedance, starting with the Packn Ra profiles. That is, if the measured
impedance matches Pack0 Ra, then the Pack0 Ra profile is used. If the measured impedance matches
Pack1 Ra, then the Pack1 Ra profile is used. If the measured impedance does not match the impedance
stored in either Pack0 Ra or Pack1 Ra, the battery pack is deemed new (not any of the previously used
packs). Either the Def0 Ra or Def1 Ra profile is copied into either the Pack0 Ra or Pack1 Ra profile,
depending on which default impedance profile most closely matches. Care is taken not to over-write the
last used Packn Ra profile.
6.2.2 Battery With Resistor ID (bq27501 Only)
The bq27501 can administrate the information of up to two battery packs. For a given pack connected to
the fuel gauge, the identity of the battery is determined by a combination of (1) reading the pack ID
resistor and (2) measuring the impedance of the currently connected pack, and (3) remembering which
pack characteristics were most recently used by the gauge.
A battery pack’s ID resistor should connect to the RID pin of the fuel gauge. Either 'A' Ω or 'B' Ω resistor
values should be used, to indicate the battery type. If a battery connection is detected, bq27501 measures
the voltage developed at RID. If the voltage is Pack 0 Voltage, then it is identified as battery pack with 'A'
resistor and bq27501 will use the Pack0 Ra profile. If the voltage measured is Pack 1 Voltage then it is
identified as battery pack with 'B' resistor and the bq27501 will use Pack1 Ra profile. The measurement
window around each threshold is specified by Pack V% Range, which indicates the positive or negative
deviation around each level. Choosing RID values of 500Ω and 8kΩ for 'A' and 'B', correspond to Pack 0
Voltage and Pack 1 Voltage threshold levels of 110mV and 1070mV, respectively. These resistance
values assume a 300Ω resistance already exists in front of the RID pin for ESD protection.
If the bq27501 measures a voltage other than Pack 0 Voltage or Pack 1 Voltage, then it sets the
Application Configuration[UNSUPBAT] to ‘1’, alerting the system that the inserted battery is not
supported. The system can use this information to download the default profile for this battery if one
exists. The system should unseal the gauge, then download the new battery profile into the older Defn Ra
memory profile. The last-used profile is indicated by the Application Configuration[LU_PROF] bit.
Overwriting the older default profile allows the bq27501 to retain information stored regarding the most
recently used battery. After the new default profile is downloaded, the bq27501 clears the Application
Configuration[UNSUPBAT].
When the bq27501 starts operation for the first time, it copies the Def0 Ra profile into the Pack0 Ra profile
and the Def1 Ra profile into the Pack1 Ra profile. Then when a battery pack is inserted for the first time,
the bq27501 starts gauging using Pack0 Ra profile if the voltage measured on the RID pin is Pack 0
Voltage, or starts gauging using Pack1 Ra profile if the voltage measured on the RID pin is Pack 1
Voltage. The Impedance Track™ algorithm regularly updates the specific Packn Ra profile as the battery
is used.
If a pack is replaced with a second pack having the same resistor ID as the first, cell impedance is
This impedance is compared with the associated Packn Ra and Defn Ra profiles that correspond to the
current RID. If the impedance matches the Packn Ra impedance then the Packn Ra profile is used. If not,
the bq27501 resets the Packn Ra data, by copying the Defn Ra profile into the Packn Ra profile (this
operation overwrites the previously stored information). The Impedance Track™ algorithm begins
converging on the data for the new battery and storing it in the Packn Ra profile.
32
APPLICATION-SPECIFIC INFORMATION
Submit Documentation Feedback
Download from Www.Somanuals.com. All Manuals Search And Download.
bq27500
bq27501
System-Side Impedance Track™ Fuel Gauge
SLUS785–SEPTEMBER 2007
7 COMMUNICATIONS
7.1 I2C INTERFACE
The fuel gauge supports the standard I2C read, incremental read, one-byte write quick read, and
functions. The 7-bit device address (ADDR) is the most significant 7 bits of the hex address and is fixed as
1010101. The 8-bit device address is therefore 0xAA or 0xAB for write or read, respectively.
Host generated
Fuel Gauge Generated
(a) 1-byte write
(b) quick read
(c) 1-byte read
(d) incremental read
(S = Start, Sr = Repeated Start, A = Acknowledge, N = No Acknowledge, and P = Stop).
Figure 7-1. Supported I2C Formats
The quick read returns data at the address indicated by the address pointer. The address pointer, a
register internal to the I2C communication engine, increments whenever data is acknowledged by the
bq27500 or the I2C master. Quick writes function in the same manner and are a convenient means of
sending multiple bytes to consecutive command locations (such as two-byte commands that require two
bytes of data).
Attempt to write a read-only address (NACK after data sent by master):
Attempt to read an address above 0x7F (NACK command):
Attempt at incremental writes (NACK all extra data bytes sent):
Incremental read at the maximum allowed read address:
The I2C engine releases both SDA and SCL if the I2C bus is held low for t(BUSERR). If the fuel gauge was
holding the lines, releasing them frees the master to drive the lines. If an external condition is holding
either of the lines low, the I2C engine enters the low-power sleep mode.
Submit Documentation Feedback
COMMUNICATIONS
33
Download from Www.Somanuals.com. All Manuals Search And Download.
bq27500
bq27501
System-Side Impedance Track™ Fuel Gauge
SLUS785–SEPTEMBER 2007
8 REFERENCE SCHEMATICS
8.1 SCHEMATIC
34
REFERENCE SCHEMATICS
Submit Documentation Feedback
Download from Www.Somanuals.com. All Manuals Search And Download.
PACKAGE OPTION ADDENDUM
25-Sep-2007
PACKAGING INFORMATION
Orderable Device
Status (1)
Package Package
Pins Package Eco Plan (2) Lead/Ball Finish MSL Peak Temp (3)
Qty
Type
SON
SON
Drawing
BQ27500DRZR
BQ27500DRZT
ACTIVE
ACTIVE
DRZ
12
12
3000
250
TBD
TBD
Call TI
Call TI
Call TI
Call TI
DRZ
(1) The marketing status values are defined as follows:
ACTIVE: Product device recommended for new designs.
LIFEBUY: TI has announced that the device will be discontinued, and a lifetime-buy period is in effect.
NRND: Not recommended for new designs. Device is in production to support existing customers, but TI does not recommend using this part in
a new design.
PREVIEW: Device has been announced but is not in production. Samples may or may not be available.
OBSOLETE: TI has discontinued the production of the device.
(2)
Eco Plan - The planned eco-friendly classification: Pb-Free (RoHS), Pb-Free (RoHS Exempt), or Green (RoHS & no Sb/Br) - please check
http://www.ti.com/productcontent for the latest availability information and additional product content details.
TBD: The Pb-Free/Green conversion plan has not been defined.
Pb-Free (RoHS): TI's terms "Lead-Free" or "Pb-Free" mean semiconductor products that are compatible with the current RoHS requirements
for all 6 substances, including the requirement that lead not exceed 0.1% by weight in homogeneous materials. Where designed to be soldered
at high temperatures, TI Pb-Free products are suitable for use in specified lead-free processes.
Pb-Free (RoHS Exempt): This component has a RoHS exemption for either 1) lead-based flip-chip solder bumps used between the die and
package, or 2) lead-based die adhesive used between the die and leadframe. The component is otherwise considered Pb-Free (RoHS
compatible) as defined above.
Green (RoHS & no Sb/Br): TI defines "Green" to mean Pb-Free (RoHS compatible), and free of Bromine (Br) and Antimony (Sb) based flame
retardants (Br or Sb do not exceed 0.1% by weight in homogeneous material)
(3)
MSL, Peak Temp. -- The Moisture Sensitivity Level rating according to the JEDEC industry standard classifications, and peak solder
temperature.
Important Information and Disclaimer:The information provided on this page represents TI's knowledge and belief as of the date that it is
provided. TI bases its knowledge and belief on information provided by third parties, and makes no representation or warranty as to the
accuracy of such information. Efforts are underway to better integrate information from third parties. TI has taken and continues to take
reasonable steps to provide representative and accurate information but may not have conducted destructive testing or chemical analysis on
incoming materials and chemicals. TI and TI suppliers consider certain information to be proprietary, and thus CAS numbers and other limited
information may not be available for release.
In no event shall TI's liability arising out of such information exceed the total purchase price of the TI part(s) at issue in this document sold by TI
to Customer on an annual basis.
Addendum-Page 1
Download from Www.Somanuals.com. All Manuals Search And Download.
Download from Www.Somanuals.com. All Manuals Search And Download.
Download from Www.Somanuals.com. All Manuals Search And Download.
Download from Www.Somanuals.com. All Manuals Search And Download.
IMPORTANT NOTICE
Texas Instruments Incorporated and its subsidiaries (TI) reserve the right to make corrections, modifications, enhancements,
improvements, and other changes to its products and services at any time and to discontinue any product or service without notice.
Customers should obtain the latest relevant information before placing orders and should verify that such information is current and
complete. All products are sold subject to TI’s terms and conditions of sale supplied at the time of order acknowledgment.
TI warrants performance of its hardware products to the specifications applicable at the time of sale in accordance with TI’s
standard warranty. Testing and other quality control techniques are used to the extent TI deems necessary to support this
warranty. Except where mandated by government requirements, testing of all parameters of each product is not necessarily
performed.
TI assumes no liability for applications assistance or customer product design. Customers are responsible for their products and
applications using TI components. To minimize the risks associated with customer products and applications, customers should
provide adequate design and operating safeguards.
TI does not warrant or represent that any license, either express or implied, is granted under any TI patent right, copyright, mask
work right, or other TI intellectual property right relating to any combination, machine, or process in which TI products or services
are used. Information published by TI regarding third-party products or services does not constitute a license from TI to use such
products or services or a warranty or endorsement thereof. Use of such information may require a license from a third party under
the patents or other intellectual property of the third party, or a license from TI under the patents or other intellectual property of TI.
Reproduction of TI information in TI data books or data sheets is permissible only if reproduction is without alteration and is
accompanied by all associated warranties, conditions, limitations, and notices. Reproduction of this information with alteration is an
unfair and deceptive business practice. TI is not responsible or liable for such altered documentation. Information of third parties
may be subject to additional restrictions.
Resale of TI products or services with statements different from or beyond the parameters stated by TI for that product or service
voids all express and any implied warranties for the associated TI product or service and is an unfair and deceptive business
practice. TI is not responsible or liable for any such statements.
TI products are not authorized for use in safety-critical applications (such as life support) where a failure of the TI product would
reasonably be expected to cause severe personal injury or death, unless officers of the parties have executed an agreement
specifically governing such use. Buyers represent that they have all necessary expertise in the safety and regulatory ramifications
of their applications, and acknowledge and agree that they are solely responsible for all legal, regulatory and safety-related
requirements concerning their products and any use of TI products in such safety-critical applications, notwithstanding any
applications-related information or support that may be provided by TI. Further, Buyers must fully indemnify TI and its
representatives against any damages arising out of the use of TI products in such safety-critical applications.
TI products are neither designed nor intended for use in military/aerospace applications or environments unless the TI products are
specifically designated by TI as military-grade or "enhanced plastic." Only products designated by TI as military-grade meet military
specifications. Buyers acknowledge and agree that any such use of TI products which TI has not designated as military-grade is
solely at the Buyer's risk, and that they are solely responsible for compliance with all legal and regulatory requirements in
connection with such use.
TI products are neither designed nor intended for use in automotive applications or environments unless the specific TI products
are designated by TI as compliant with ISO/TS 16949 requirements. Buyers acknowledge and agree that, if they use any
non-designated products in automotive applications, TI will not be responsible for any failure to meet such requirements.
Following are URLs where you can obtain information on other Texas Instruments products and application solutions:
Products
Amplifiers
Data Converters
DSP
Applications
Audio
amplifier.ti.com
dataconverter.ti.com
dsp.ti.com
Automotive
Broadband
Digital Control
Military
Interface
interface.ti.com
logic.ti.com
Logic
Power Mgmt
Microcontrollers
RFID
power.ti.com
Optical Networking
Security
microcontroller.ti.com
Telephony
Low Power
Wireless
Video & Imaging
Wireless
Mailing Address: Texas Instruments, Post Office Box 655303, Dallas, Texas 75265
Copyright © 2007, Texas Instruments Incorporated
Download from Www.Somanuals.com. All Manuals Search And Download.
|