S3F84B8
All-in-One IH Cooker
Revision 0.00
May 2010
Application Note
2010 Samsung Electronics Co., Ltd. All rights reserved.
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Revision History
Revision No. Effective Date
0.00 Mar, 2010
Description
Refer to
Author(s)
- Initial Draft
Wei Ningning
Zhang Fan
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Table of Contents
1.1 Induction Cooking Principle ..................................................................................................................... 1-1
1.1.1 How Induction Cooking Works ......................................................................................................... 1-1
1.2 Key Features of S3F84B8........................................................................................................................ 1-2
1.3 System Principle ...................................................................................................................................... 1-3
1.3.1 Heating ............................................................................................................................................. 1-3
1.3.2 Protection.......................................................................................................................................... 1-3
2.1 System Diagram and pin Assignment...................................................................................................... 2-4
2.2 Power Supply........................................................................................................................................... 2-6
2.3 Synchronization Circuit ............................................................................................................................ 2-7
2.4 Power control ........................................................................................................................................... 2-9
2.4.1 Voltage Measurement ...................................................................................................................... 2-9
2.4.2 Current Measurement..................................................................................................................... 2-10
2.5 System Protection.................................................................................................................................. 2-11
2.5.1 Surge Protection............................................................................................................................. 2-11
2.5.2 IGBT over Voltage Protection......................................................................................................... 2-11
2.5.3 Over/under Voltage Protection ....................................................................................................... 2-11
2.5.4 Temperature Protection.................................................................................................................. 2-12
2.6 Other Functions...................................................................................................................................... 2-13
2.6.1 Pan Detection ................................................................................................................................. 2-13
2.6.2 Buzzer and Fan Control.................................................................................................................. 2-13
2.6.3 Key and Display Circuit .................................................................................................................. 2-14
3.1 State Transition Diagram ......................................................................................................................... 3-1
3.2 Software Diagram .................................................................................................................................... 3-2
3.3 Internal Resource Arrangement and Configuration ................................................................................. 3-4
4 APPENDIX...................................................................................................4-1
4.1 Error Code................................................................................................................................................ 4-1
4.2 Schmatic .................................................................................................................................................. 4-1
4.3 Source Code ............................................................................................................................................ 4-1
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List of Figures
Figure
Title
Page
Number
Number
Figure 1-1 How IH Cooker Works ...................................................................................................................... 1-1
Figure 1-2 Pin Assignment in S3F84B8............................................................................................................. 1-2
Figure 2-1 Block Diagram of IH Cooker System................................................................................................ 2-4
Figure 2-2 Power Supply Circuit ........................................................................................................................ 2-6
Figure 2-3 Power Supply Circuit ........................................................................................................................ 2-7
Figure 2-4 Waveform of the Synchronization Circuit ......................................................................................... 2-8
Figure 2-5 Voltage Measurement and Surge Protection Circuit ........................................................................ 2-9
Figure 2-6 Current Measurement Circuit.......................................................................................................... 2-10
Figure 2-7 Over-Temperature Protection......................................................................................................... 2-12
Figure 2-8 Buzzer and Fan Control.................................................................................................................. 2-13
Figure 2-9 Key and Display Circuit................................................................................................................... 2-14
Figure 3-1 State Transition Diagram.................................................................................................................. 3-1
Figure 3-2 Software Diagram............................................................................................................................. 3-2
Figure 3-3 Interrupt Service Routine Diagram ................................................................................................... 3-3
Figure 3-4 Fan and BUZ Workflow..................................................................................................................... 3-3
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List of Tables
Table
Title
Page
Number
Number
Table 2-1 S3F84B8 pin assignment in IH cooker system.................................................................................. 2-5
Table 3-1 Internal Resource Arrangement and Configuration ........................................................................... 3-4
Table 4-1 Error Information................................................................................................................................ 4-1
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1 OVERVIEW OF IH COOKER (IHC)
1
OVERVIEW OF IH COOKER (IHC)
In traditional ranges or ovens, cookware is used to transfer heat from the stove elements. However, in the IH
cooker (IHC), the cookware participates in the heat generation. This form of heat generation is known as Induction
Heating, and it improves the overall thermal efficiency of heating.
This document describes an IH cooker (IHC) system implemented with Samsung’s newly developed 8-bit MCU
S3F84B8, which is designed for an all-in-one IHC application with amplifier and comparators.
1.1 INDUCTION COOKING PRINCIPLE
According to Faraday’s Law, changing the magnetic field associated with an alternating current (AC) induces
current in a second conductor placed in that field. IH cookers work largely the same way.
1.1.1 HOW INDUCTION COOKING WORKS
This section describes how induction cooking works.
Steps:
1) The electronic components in the element power a coil, which in turn produces a high-frequency
electromagnetic field.
2) The electromagnetic field enters the ferrous metal (magnetic material) of the cookware and sets up a
circulating electric current (Eddy current), which generates heat.
3) The heat generated in the cookware is transferred internally.
4) The electromagnetic field does not affect the outer body of cookware. As soon as the cookware is removed
from the element or the element turned off, the heat generation stops.
Figure 1-1 How IH Cooker Works
1-1
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1 OVERVIEW OF IH COOKER (IHC)
1.2 KEY FEATURES OF S3F84B8
With no more discrete ICs like LM339 (comparator IC) in previous IHC solutions, S3F84B8 successfully integrates
four comparators, one OPA, and one IH-PWM to control power directly. After configuration, all the four
comparators can cooperate with the IH-PWM automatically, which makes the time-sensitive control possible.
Figure2 shows the pin assignment in S3F84B8.
VSS
INT0/XIN/P0.0
INT1/XOUT/P0.1
PP/nRESET/P0.2
BUZ/INT2/P0.3
PWM/INT3/P0.4
INT4/P0.5
1
20
19
18
17
16
15
14
13
12
11
VDD
2
P2.7/ADC7/(SCL)
P2.6/ADC6/(SDA)
P2.5/ADC5/CMP3_N
P2.4/ADC4/CMP2_N
P2.3/ADC3(OPA_O)
P2.2/ADC2/OPA_N
P2.1/ADC1/OPA_P
P2.0/ADC0/TDOUT
P1.2/CMP1_N
3
V
4
5
S3F84B8
6
20-DIP/
20-SOP
7
TAOUT/INT5/P0.6
TACK/CMP0_P/P1.0
TACAP/CMP0_N/P1.1
8
9
10
Figure 1-2 Pin Assignment in S3F84B8
The key features of S3F84B8 include:
8K Full Flash ROM and 272B SRAM
Four Comparators
One OPA
10-bit IH-PWM x 1 (can co-operate with the four Comparators)
10-bit ADC x 8
8-bit Basic Timer (can be used as Watch Dog Timer)
8-bit TimerA
16-bit Timer0 (can be used as two 8-bit Timers C/D)
External Interrupts X 6
Supports configurable LVR (1.9/2.3/3.6/3.9V)
Supports configurable internal RC (0.5M/8MHz RC @5V with maximum 3% accuracy)
Supports 18 IOs (maximum) when using internal LVR and internal RC
Comparator0 has two inputs. Its output can trigger the PWM to start a new cycle immediately or after some
programmable delay. This helps in the synchronization control. The delay can adjust the IGBT to turn on at
minimum collector voltage, thereby reducing the heat and protecting the transistor.
1-2
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1 OVERVIEW OF IH COOKER (IHC)
Comparator1/2/3 has only one input with an internal programmable reference level. It can lock the output of PWM
to a safe level. Besides the delay trigger function, PWM can realize anti-mis-trigger function as well. It prevents
the PWM from being triggered by unexpected noise. For more information about the cooperating mechanism of
the IH-PWM and four comparators, refer to the user’s manual.
1.3 SYSTEM PRINCIPLE
To make the system work reliably, the control of IH cooker can be divided into two major parts: heating and
protection.
1.3.1 HEATING
In earlier solutions, the output of LM339 controls the IGBT. On being filtered, the PWM output transforms into an
analog signal that sets the flip level of LM339. Therefore, only the duty determines the output power.
However, in a system with S3F84B8, the PWM directly controls the switch of IGBT and the width of valid output
level determines the output power. Therefore, the power is dependent on the system clock.
1.3.2 PROTECTION
Two kinds of protection are available for the control of IH cooker: first is time sensitive protection, and the other is
acceptable protection that can be executed even after certain degree of delay.
Surge protection and IGBT over-voltage protection belong to the former class (time sensitive protection).
Therefore, these two signals use the integrated comparators. In this solution, PWM will be hard-locked when
surge protection is triggered. It stops the PWM with a safe output level until the software enables it again. Once
the voltage sensed at IGBT is beyond limitation, PWM will be soft-locked. This will make the PWM stop the current
cycle and reload PWMDATA with a preset safe value (PWMPDATA) to reduce the turn-on time of IGBT from that
instance.
Over-temperature, over-current, and over/under voltage protections belong to the latter class. They are realized by
AD conversion and software comparison.
1-3
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2 HARDWARE IMPLEMENTATION
2
HARDWARE IMPLEMENTATION
2.1 SYSTEM DIAGRAM AND PIN ASSIGNMENT
Figure 2-1 shows the block diagram of IH cooker system.
Figure 2-1 Block Diagram of IH Cooker System
2-4
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2 HARDWARE IMPLEMENTATION
In Figure 2-1, SMPS stands for Switch Mode Power Supply. It provides +18V DC and +5V DC to the system.
Three out of four comparators are used in this solution: one for synchronization circuit and other two for surge
protection and IGBT over-voltage protection.
Table 2-1 shows the pin assignment while using S3F84B8 in IH cooker system.
Table 2-1 S3F84B8 pin assignment in IH cooker system
Pin No.
1
Pin Names
VSS
Pin Type
Pin Assignment
I
I
Ground
20
4
VDD
Power input
Reserved
P0.2
-
2
P0.0
O
O
O
O
O
O
O
I
Display Board
Connector
DIO
3
P0.1
CLK
STB
7
P0.5
8
P0.6
Reserved
13
5
P2.1
Reserved
P0.3/BUZ
P0.4/PWM
P1.0/CMP0_P
P1.1/CMP0_N
P1.2/CMP1_N
P2.4/CMP2_N
P2.5/ADC5
P2.0/ADC0
P2.7/ADC7
P2.6/ADC6
P2.2/OPA_N
P2.3/OPA_O
Buzzer and Fan control
IGBT control
6
9
Synchronization control
10
11
16
17
12
19
18
14
15
I
I
IGBT over-voltage protection
Surge protection
I
I
System voltage measurement input
IGBT temperature sensor input
Pan temperature sensor input
Amplified current signal input
System current measurement input
Operational Amplifier output
I
I
I
I
O
2-5
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2 HARDWARE IMPLEMENTATION
2.2 POWER SUPPLY
Figure 2-2 shows the circuit diagram for power supply.
D6
AC_L
220 VAC
D7
L1
1N4007
D1
T1
D4 UF4007
+18V
1
4
5
6
8
AC_N
D7 UF4007
330uH
R1
100K/0.5W
1N4007
1N4007
C1
102/1KV
+
C6
100uF/25V
EE-19
78L05
D2
UF4007
+
C2
4.7uF/450V
U1
Z1
18V
+
C21
100uF/25V
8
7
6
5
1
2
3
4
UF4007
D5
1
3
2
+5V
D4
D3
D2
S1
S2
FB
VIN
VOUT
GND
+
C13
100uF/16V
D1 VDD
IC1
VIPER12A
+
C8
C3
10uF/50V
104
Figure 2-2 Power Supply Circuit
The power circuit contains a transformer, an SMPS primary switcher, and a +5V DC regulator. After passing
through a half-wave rectifier and an LC filter, the 220V AC power enters the primary side of transformer.
Thereafter, VIPER12 and 78L05 produce stable +18V DC power for the transistors and +5V DC power for the
MCU and other devices.
2-6
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2 HARDWARE IMPLEMENTATION
2.3 SYNCHRONIZATION CIRCUIT
+18V
R28 51R
R22
2K
R21
2K
C28
25V/100uF
+
D8
Q4
COOKER
4148
8050
L2
FUSE1
Q1
R23 2K
AC_L
L3
R36
8050
10A/250V
CHOKE
8550
Q5
C23 102
PWM
C20
0.24uF/1200V
IGBT
10R
Q2
8050
IGBT_CTRL
FGA15N120
C19
-
+
C22
0.1uF/275V
2
4
C17
101
4uF/400V
R37
10K
R24
1K
BRIDGE
D15XB80H18
R50
CONSTANTAN
AC_N
IGBT Driver
SYS_I
R2
220K/0.5W
R6
220K/0.5W
R3
470K/0.5W
R7
220K/0.5W
R10
470K/0.5W
R8
220K/0.5W
R25
Syn_N
Syn_P
24K
R9
2KJ
R11
5K6
IGBT_V_P
IGBT over voltage protection
R12
2K7
Figure 2-3 Power Supply Circuit
2-7
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2 HARDWARE IMPLEMENTATION
IH heating is the result of Eddy current caused by LC resonance. For a general cookware, the oscillation
frequency may vary from 20KHz to 30KHz. Since heating consumes energy, the IGBT should be periodically
turned on to allow the 220V power to compensate for the energy loss. Obviously, the longer it is turned on, the
more energy can be accumulated.
When the PWM output turns on the IGBT, electric energy is stored in the inductance and free LC oscillation is
To make the system work stably, consider the turn on frequency and turn on time of the IGBT. First, the turn on
frequency cannot destroy the LC oscillation, even though the IGBT on time will affect it a little bit. This means the
frequency of PWM output should be synchronized with the LC oscillation. It is realized by comparator0.
Second, considering the withstand voltage of IGBT, it is better to turn it on when the collector voltage is near ‘0’. It
can be realized by adjusting the divider resistors and enabling the delay trigger function of the IH PWM module. At
the same time, when proper delay time is set, thermal radiations will be largely reduced.
Figure6 shows the waveform of synchronization circuit. Light and dark blue waveforms show the inputs of
comparator0. The green waveform is measured at P0.4 (PWM). Additionally, the crossing point of the light and
dark blue waveforms trigger the rising of PWM output (High level at the base) which turns on the IGBT. The
duration of PWM’s outputting high is the result of software power control. When PWM output (green waveform)
returns to low level, the light and dark waveform presents free oscillation of the circuit, though the existence of the
IGBT diode makes the oscillation waveform not an ideal one.
Figure 2-4 Waveform of the Synchronization Circuit
2-8
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2 HARDWARE IMPLEMENTATION
2.4 POWER CONTROL
Power is the product of voltage and current (P = V x I). Figure 2-5 and Figure 2-6 show the measurement circuit of
system voltage and current, separately.
2.4.1 VOLTAGE MEASUREMENT
Figure 2-5 shows the circuit diagram for voltage measurement and surge protection.
1N4007
D9
AC_L
220 VAC
D10
AC_N
R17
470K/0.5W
1N4007
R18
R19
820K/0.5W 820K/0.5W
surge protection
C15
102/1KV
Surge_P
SYS_V
R27
6K8
R20
29K
+
C16
10uF/50V
C18
221
Figure 2-5 Voltage Measurement and Surge Protection Circuit
Resistor divider decreases the voltage level to the proper ADC range.
2-9
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2.4.2 CURRENT MEASUREMENT
2 HARDWARE IMPLEMENTATION
SYS_I
OPA_N
OPA_O
R4 1K
Rf
C10
104J
RW1
CURRENT
R13 36K
R14 100K
R1
OPA_N
OPA_O
10K
R15
22K
+
OPA_P
C12
1uF/16V
3F84BS8
Gain=-Rf/R1
Figure 2-6 Current Measurement Circuit
In the IH cooker system, the current can go as high as 10A. To avoid excessive energy loss, a constantan is used
to change the current signal to voltage signal, which is then amplified by the integrated OPA. Finally, the amplified
signal enters the ADC module. Note that the signal (OPA_N) reaching OPA is negative as compared to MCU
GND. Therefore, OPA has to work as an inverting amplifier with negative gain.
Either the OPA offset or the resistance deviation can lead to inconsistency of output power among different chips.
To get precise power control, two calibrating methods are used. In hardware, a variable resistor (RW1) is chosen,
whereas in software algorithm, the overall offset is measured and calculated before the system starts working. It
likes the quiescent bias that should be removed during normal operation. This way the output power can be
controlled within 10W deviation.
2-10
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2 HARDWARE IMPLEMENTATION
2.5 SYSTEM PROTECTION
2.5.1 SURGE PROTECTION
Figure 2-5 shows the circuit diagram for surge protection. In this figure, Surge_P specifies the negative input of
Comparator 1. Also, reference voltage is internally set as 0.55VDD. When surge takes place, that is, V Surge_P >
0.55VDD, the falling edge of comparator 1 can hard-lock the PWM output immediately to prevent the IGBT from
being burnt out by over current. The whole system then stops work and restarts after some delay.
2.5.2 IGBT OVER VOLTAGE PROTECTION
IGBT over voltage is most likely to occur the moment when the pan is removed from the panel.
Figure 2-5 shows the voltage measurement circuit. In this figure, IGBT_V_P specifies the negative input of
Comparator 2. Also, reference voltage internally is set as 0.70VDD. When V Surge_P > 0.70VDD, the co-
operation of comparator 2 and IH PWM will soft-lock the PWM output immediately to prevent the IGBT from being
burnt out by over stress of the collector voltage. As a result, it makes the PWM stop the current cycle and reload
PWMDATA with a preset safe value (PWMPDATA) to reduce the turn-on time of IGBT.
2.5.3 OVER/UNDER VOLTAGE PROTECTION
Over/under voltage protection uses the voltage measurement signal. The protection takes place when the AD
conversion result is either too large or too small. The whole system then stops working until the power returns to
normal.
2-11
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2 HARDWARE IMPLEMENTATION
2.5.4 TEMPERATURE PROTECTION
Figure 2-7 shows the circuit diagram for temperature protection.
+5V
CN5
PAN_T
RT1
100K3950
2
1
+5V
IGBT_T
T_PAN
C25 R29
104 3K
R5
C4
10K
104
b) IGBT temperature protection
a) Pan temperature protection
Figure 2-7 Over-Temperature Protection
RT1 is a thermistor located just beneath the IGBT. CN5 is the connector for the thermistor near the pan.
For IGBT temperature protection, there are two kinds of scenarios:
When the temperature rises above 85℃, the set level of output power will automatically downgrade.
When the temperature continues to rise above 90℃, the system will shut down and will remain in that state
until it is restarted manually.
For pan temperature, the system will be shut down when the temperature is over 230℃.
The threshold of protection level can differ, according to the different locations of the thermistor.
Meantime, when the sensed voltage level is close to 5V or 0V, the sensor can be viewed as broken. The whole
system then stops working until it is restarted manually.
2-12
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2 HARDWARE IMPLEMENTATION
2.6 OTHER FUNCTIONS
2.6.1 PAN DETECTION
Pan-on detection is executed every 2sec when the system is idle. It is useful when you press the Start key first
and then put the pan on. In principle, even though the IGBT is turned on, there will not be any oscillation before
the pan is put on the panel. In S3F84B8, comparator 0’s output can be set as the clock source of Timer C. After
starting 1-cycle PWM output and waiting for about 3 oscillation cycles, if TCCNT>1, Pan status = on; else Pan
status = off. Pan-remove detection is executed every 1.5s when the system is working. It is useful when you
directly remove the pan from the panel without pressing the Stop key.
Pan-remove detection is done by current measurement, that is, when the sensed current is small, the system
considers the pan as removed and turns idle.
2.6.2 BUZZER AND FAN CONTROL
Figure 2-8 shows the circuit diagram for buzzer and fan control.
BUZZER1
C24 104M/50V
BUZ/FAN
+18V
CN3
R26
1K
1
2
Q3
8050
FAN
Figure 2-8 Buzzer and Fan Control
The fan cools down the system while heating. Buzzer indicates error and key actions.
In Figure 2-8, buzzer and fan share the same I/O. Due to C24, the DC signal controls fans on and off, while
square wave with high frequency determines the buzzer’s beep.
Note that C24 cannot be too large; else it will deteriorate the power of MCU and make the integrated analog
modules work unstably.
2-13
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2 HARDWARE IMPLEMENTATION
2.6.3 KEY AND DISPLAY CIRCUIT
Figure 2-9 shows the circuit diagram for key and display.
5V
1
R6
2
D1
SEG1/KS1
SEG4/KS4
R32
conRs2t9ant
coRns8tant
constant
1
1
1
1
2
2
2
2
U2
NC
DIO
CLK
constant
1
2
3
4
5
6
7
8
9
10
11
12
13
14
28
27
26
25
24
23
22
21
20
19
18
17
16
15
LED
D2
GND0
GRID1
GRID2
GND
GRID3
GRID4
GND
GRID1
GRID2
GND
GRID3
GRID4
GND1
VDD1
D8
STB
KEY1
KEY2
5V
SEG1/KS1
SEG2/KS2
SEG3/KS3
SEG4/KS4
SEG5/KS5
SEG6/KS6
SEG7/KS7
LED
D3
KEY1
KEY2
VDD0
5V
SEG1/KS1
GRID5
GRID6
GRID7
LED
D4
SEG2/KS2 SEG14/GRID5
SEG3/KS3 SEG13/GRID6
SEG4/KS4 SEG12/GRID7
SEG5/KS5
SEG6/KS6
SEG7/KS7
SEG3/KS3
4LED
SEG10
SEG9
SEG8/KS8
LED
SEG8/KS8
GRID7
TM1628
K4 KEY
K2 KEY
KEY1
KEY2
5V
K3
K1
K5
K6
K7
K8
+
C26
PF
C27
PF
R18 constant
0
GND
0
KEY
KEY
KEY
KEY
KEY
KEY
constant
R17
constant
R7
constant
R10
constant
R11
constant
R12
constant
R14
constant
R9
0
Figure 2-9 Key and Display Circuit
There are eight keys for power on, power grade selection, and some LEDs to display the operating status and
power grade. TM1628 controls the key and display circuit. MCU communicates with TM1628 through three I/Os:
DIO for data transfer, CLK as serial clock, and STB for chip enable.
2-14
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3 SOFTWARE IMPLEMENTATION
3
SOFTWARE IMPLEMENTATION
3.1 STATE TRANSITION DIAGRAM
Figure 3-1 shows the state transition diagram. This diagram illustrates the operation of IH cooker system.
Figure 3-1 State Transition Diagram
After power is turned on manually, the system periodically checks for pan status and current work condition. This
ensures the power is activated only when the pan is on panel, and all temperatures and voltage are in good
condition.
The IH cooker will stop heating immediately in case of the following issues:
Manually power off by key pressing
Error flag set as temperature or voltage is abnormal
Pan is detected to be removed
Surge protection is triggered
Note that only voltage recovery can reset the error flag to ‘0’ and restart the system, which means once the error
flag is set by IGBT/Pan over-temperature, you have to restart the system manually.
In the power on state, key pressing can alter the power. For reliability, the power will automatically downgrade
when the IGBT temperature is higher than 85℃.
3-1
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3 SOFTWARE IMPLEMENTATION
3.2 SOFTWARE DIAGRAM
Figure 3-2 shows the software diagram.
Figure 3-2 Software Diagram
NOTE:
1. [1] Pan remove detection [1] is done by current sensing. The pan is judged to be removed when the current is lower than a
preset threshold.
2. [2] Pan on detection [2] is done by pulse counting. The pan is judged to be put on when the counted pulse number is
between 1 and 3 during 3 oscillation period.
Basic procedures include key process, error detection, power control, and UI update. These procedures are
executed as an infinite loop. Most of the processes are controlled by timing. In other words, process is executed
only when the corresponding timing flag is set. For example, 16 times AD conversion time for error detection, 1.5
second for pan-on detection, and 2 seconds for pan-remove detection.
Meanwhile, comparator1 and comparator2’s interrupts are enabled for surge protection and IGBT over-voltage
protection, separately. Therefore, the above procedure might be interrupted whenever any of the comparator 1 or
comparator 2’s interrupt condition is met.
3-2
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3 SOFTWARE IMPLEMENTATION
Figure 3-3 shows the flow chart of CMP1/2 interrupt service routine. Due to the cooperation of IH-PWM and
comparators integrated in S3F84B8, only a few jobs need to be done in the ISR.
CMP1INT ISR (hard lock)
For surge protection
CMP2INT ISR (soft lock)
For IGBT over voltage protection
Start
Start
Clr pending bit
Clr pending bit
Set P0.4(PWM) to input without pull-up R
Not mandatory
PWMCON = 0
End
End
Figure 3-3 Interrupt Service Routine Diagram
NOTE: When hard lock happens, the PWM returns to the safe value immediately.
When soft lock happens. The PWM returns to the safe value immediately for the current PWM cycle. And the
PWMDATA will be reloaded as PWMPDATA, usually a smaller one, from the next cycle on.
FAN work flow
BUZ work flow
Start
Start
N
N
Beaming for 0.2s
Power flag = 0?
Y
N
IGBT temp < 55
Y
Power flag = 1?
Y
N
Fan Off
Fan On
Pan flag = 1?
Y
N
No pan detected?
Y
Error lasts for 2s?
Y
Beaming for 0.2s
Figure 3-4 Fan and BUZ Workflow
Figure 3-4 shows the workflow of FAN and BUZ. FAN is always on as the IH cooker is generating heat. Even
when the device is powered off by manually setting or system protection, it is still on as long as the IGBT
temperature is higher than 55 ℃, in order to prevent the cooker from hot temperature damage.
Buzzer is mainly used for information indication. Besides the first beaming at power on, it only gives alarm when
some error lasts for 2sec or no pan is detected after trying 30 times
3-3
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3 SOFTWARE IMPLEMENTATION
3.3 INTERNAL RESOURCE ARRANGEMENT AND CONFIGURATION
Table 3-1 shows the internal resource arrangement and configuration.
Table 3-1 Internal Resource Arrangement and Configuration
Module
Purpose
Configuration
Registers
CMP0
Synchronization
Surge protection
Non-inverting output
Disable INT
CMP0CON
CMPINT
P1CON
CMP2
CMP1
0.50VDD reference
Non-inverting output
Enable INT
CMP1CON
CMPINT
P1CON
IGBT over-V protection
0.65VDD reference,
Non-inverting output,
Enable INT
CMP2CON
CMPINT
P1CON
OPA
Current amplification
IGBT control
On-chip mode
OPACON
P2CONL
PWM
Co-operate with CMP0
Delay Trigger
PWMCON
PWMCCON
PWMDATAH/L
PWMPDATAH/L
P0CONH
AMT Trigger
BUZ
TA
BUZ control
1KHz output
BUZCON
P0CONL
100ms timing for
Internal mode
TAPS
1) BUZ beaming time (0.2sec for every enable)
2) Display blink interval (0.5sec)
3) Error warning (BUZ) after error lasts for 2sec
4) Pan-on detect every 2sec
Match Interrupt Enable
TA Internal Clock = Fosc/4096
TACON
5) Move pan detect every 1.5sec
6) Power adjust every 0.1sec
7) Check sensor status after 3min of heating up
TC
Pulse counting for pan detection
Interval mode
TCCON
TCPS
Interrupt Disable
TC clock = CMP0_O
Table 3-1 shows the internal resource arrangement for IH cooker system and related registers in S3F84B8. For
detail description of all the registers and co-operation ways of comparators and IH PWM, refer to the S3F84B8
user’s manual.
3-4
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4 APPENDIX
4
APPENDIX
4.1 ERROR CODE
Table 4-1 shows the error information along with the error type and its code on 7seg-LED.
Table 4-1 Error Information
Error Type
IGBT temperature sensor error
Pan temperature sensor error
Over voltage error
Error code on 7seg-LED
E1
E2
E3
E4
E5
E6
Under voltage error
IGBT over temperature error
Pan over temperature error
4.2 SCHMATIC
S3F84B8_DEMO_V0.0
_0401.pdf
4.3 SOURCE CODE
For more information about the source code, refer to the Source_Code_IHC_S3F84B8_V00.
Reference:
[2] S3F84B8 UM
4-1
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