STMicroelectronics THERM01EVAL Refrigerator Control User Manual

July 2001
DOC-THERMOSTAT Evaluation Board
1
USE IN LIFE SUPPORT DEVICES OR SYSTEMS MUST BE EXPRESSLY AUTHORIZED.
STMicroelectronics PRODUCTS ARE NOT AUTHORIZED FOR USE AS CRITICAL COMPONENTS IN
LIFE SUPPORT DEVICES OR SYSTEMS WITHOUT THE EXPRESS WRITTEN APPROVAL OF
STMicroelectronics. As used herein:
1. Life support devices or systems are those
which (a) are intended for surgical implant into
the body, or (b) support or sustain life, and
whose failure to perform, when properly used in
accordance with instructions for use provided
with the product, can be reasonably expected
to result in significant injury to the user.
1
2. A critical component is any component of a life
support device or system whose failure to
perform can reasonably be expected to cause
the failure of the life support device or system,
or to affect its safety or effectiveness.
REFRIGERATOR CONTROL
EVALUATION BOARD
USER MANUAL
1 INTRODUCTION
1.1 TARGET APPLICATION
The THERM01EVAL board is designed to be a complete MCU-controlled thermostat application when used with a M2020 12k NTC thermal sensor, from EPCOS (supplied with the kit).
This thermostat can be used to control a single-phase induction motor, and works with a 220240 V RMS 50 Hz mains voltage. The board can operate in an ambient temperature range of
0 to 60 °C. The exact maximum temperature will depend on the power of the loads (see Section 3.1).
This type of motor, used to drive a compressor, usually has an auxiliary winding that only
works during the first 0.5 s of operation, in order to apply a higher torque at start-up. Traditionally, a PTC resistor is used to switch-off this winding after start-up. The THERM01EVAL board
allows this PTC to be switched-off, after motor turn-on, or to be completely removed, in order
to reduce the power consumption caused by the PTC heating up. In fact, the two windings can
be controlled by two triacs. However, only one triac can be used to drive the compressor if the
PTC is to be left working.
Warning:
The MCU is directly linked to the mains voltage. No insulation is
ensured between the accessible parts and the high voltage. The
THERM01EVAL board must be used with care and only by persons
qualified for working with electricity at mains voltage levels.
This document gives all the information needed to make the board work (how to connect it,
how it works). To have specific information at design level, in order to modify certain parameters, please refer to the two following Application Notes:
AN1353: ST6200C Software Description for Cooling Thermostat Applications
AN1354: Single-phase Induction Motor Drive for Refrigerator Compressor Applications
Rev. 1.1
July 2001
3/20
Table of Contents
1 INTRODUCTION . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3
1.1 TARGET APPLICATION . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3
1.2 BLOCK DIAGRAM . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5
1.3 LIST OF CONTENTS . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5
1.4 GETTING STARTED . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5
2 FUNCTIONAL DESCRIPTION . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 7
2.1 PERFORMANCE . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 7
2.2 MAIN FEATURES . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 8
2.2.1 Temperature control . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 8
2.2.2 Motor control . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 8
2.2.3 Light bulb . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 8
2.3 HARDWARE DESCRIPTION . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 8
2.3.1 ACS & ACST devices . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 8
2.3.2 ST6200C Microcontroller . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 9
2.3.3 Capacitive power supply . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 9
3 USING THE EVALUATION BOARD . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 10
3.1 CURRENT LOADS . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 10
3.2 CONTROL PULSES . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 10
3.3 OVERCURRENT DETECTION . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 11
3.4 MEASUREMENT POINTS . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 11
4 CONCLUSION . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 12
Appendix 1 – Thermal Sensor Linearization . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 13
Appendix 2 – Wiring connections . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 15
Appendix 3 – THERM01EVAL Schematics . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 17
Appendix 4 – Bill of Materials . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 18
Appendix 5 – Procedure for IEC61000-4-4 Voltage Burst Test . . . . . . . . . . . . . . . . 19
20
4/20
1
INTRODUCTION
1.2 BLOCK DIAGRAM
Figure 1 shows the block diagram of the THERM01EVAL board.
Start
ACST6 +
RC
snubber
DOOR
connec tor
Capacitive
Power
Supply
ST62T00C
FUSE
Ts
protective
inductor
Overcurrent
Warning LED
ACS102
Compressor
connector
Shunt
resistor
THERM01EVAL
NTC
connec tor
Door Switch
Figure 1. Thermostat evaluation board block diagram
Run
ACST6 +
RC
snubber
BULB
connector
MAINS
connector
Temperature
order
potentiometer
1.3 LIST OF CONTENTS
The following items are supplied in this package:
– A thermostat board (ref.: THERM01EVAL) (including the ST62T00C MCU programmed
with the software described in Application Note AN1353)
– A M2020 12 k EPCOS NTC
– A CD-ROM, including ST and EPCOS product presentations and datasheets, and the
SOFTWARE programmed in the ST62T00C microcontroller (demov1r3.st6 file)
– A User Manual (this document).
1.4 GETTING STARTED
To operate the THERM01EVAL board correctly, use the following procedure:
1. Check that the programmed pulses for generating the current for the ACS / ACST gates,
are compatible with the motor to be controlled (see Section 3.2).
This means that the START and RUN winding currents must be lower than the ACST6
holding and latching currents (25 and 50 mA respectively) in a 2.8 ms window, starting
5/20
INTRODUCTION
0.45 ms after the Zero Crossing point of the mains voltage (see Figure 2).
To change the pulse timing, refer to Application Note AN1353.
Two motor control parameters should also be checked, i.e. the length of the START winding conduction and the delay after which the overcurrent subroutine operates (cf. AN1353
& AN1354).
These two times can be lengthened if they are too short and do not meet the requirements of the motor you are using.
2. Check that the power of the motor and the bulb to be controlled is not too high (see Section 3.1):
–Bulb power < 25 W
–Compressor power < 150 W
3. Check that the programmed threshold level (4 °C by default) of the temperature Hysteresis control is compatible with the temperature variation of the evaporator to be controlled.
If not, you can change this threshold by modifying the "THRES" variable in the software
(see Appendix 1 and AN1353).
4. If you have changed the software in steps 1 and 3 above, don't forget to program the
Option Byte as follows in your MCU:
D1 = 1 (Hardware Watchdog activation)
D6 = 1 (RC network oscillator selection)
D8 = 1 (LVD reset activation).
Unused memory should also be filled as described in Section 2.3.2.
5. Connect the board as follows (see. Figure 1):
6/20
a.
Connect the bulb to the "BULB" connector
b.
Connect the NTC to the "NTC" connector, and put the sensor terminal on the evaporator in the fridge or freezer to be controlled.
c.
Connect the switch of the appliance door (if it is not connected to any electrical potential) to the "DOOR" connector. Alternatively, instead of using an external switch
you can use the "DOORSWITCH" on the board to switch the bulb ON or OFF.
d.
Connect the Compressor to the "MOTOR" connector. Take care to connect the
"START", "RUN" and "LINE" properly to the right terminals on the motor (see appendix 2 and AN1354).
e.
Warning: all the following actions have to be done by a electrically-skilled technician, because the board has to be plugged to the MAINS voltage, and because NO
INSULATION is implemented between the MAINS voltage and the accessible conductive parts.
FUNCTIONAL DESCRIPTION
When all safety precautions have been taken, the mains voltage can be plugged
into the "MAINS" connector.
Note: The Protective Earth (PE) pin is not connected to any part of the board (but
just to a floating pad, in case it is needed).
6. Use an insulated screw-driver to switch the motor ON by turning the "TEMP ORDER"
potentiometer towards the "COLD" indication. Note that the temperature order is
refreshed every 5 seconds. The potentiometer should so not be turned too fast in order to
let the microprocessor take the new order into account . The potentiometer should not be
turned completely to the COLD position in order to avoid the fridge cooling excessively
and the motor operating too long. It is recommended to check the evaporator temperature
with a second temperature sensor.
Check that the motor is being controlled properly, for example by using an oscilloscope to
display the START and RUN winding currents (their waveforms should be sinusoidal).
7. If there are problems:
– If the overcurrent LED is switched on several times at each motor start-up, this means that
the START winding conduction and/or the overcurrent subroutine start delay are too short
and must be changed.
– Check that the board is correctly powered on by changing the "DOORSWITCH" position.
The bulb should go ON and OFF.
– Check if the FUSE is blown (disconnect the mains voltage before unplugging the fuse).
– Reset the MCU by unplugging the mains voltage and waiting for V DD to drop below 0.7 V.
Then, apply the mains voltage and try again to see if the board operates.
2 FUNCTIONAL DESCRIPTION
2.1 PERFORMANCE
The THERM01EVAL board is designed to meet the following requirements:
– Low cost: the complete board material, plus the sensor, can reach a cost close to electromechanical solutions, for high volume ranges (1 Million units per year); a lower target can
also be reached if all the options are removed (only one triac to drive the compressor, no
LED, no ACS to drive the bulb, smaller PCB area).
– Electromagnetic Compatibility: the board is able to withstand bursts of more than 3 kV
during IEC61000-4-4 standard tests without any operational problems (and up to 4.5 kV
without any damage). Surge tests have also been performed (IEC61000-4-5 standard): 2
kV bursts can be applied without any damage to the semiconductors.
– Safety standards have also been taken into account. Hence, a 2 mm creepage is ensured
between all high voltage parts and low voltage parts (to achieve the functional insulation
level). The thermal sensor is a class II sensor.
7/20
FUNCTIONAL DESCRIPTION
2.2 MAIN FEATURES
2.2.1 Temperature control
The thermal sensor is an NTC resistor from EPCOS (M2020 12 k 2%). It should be placed on
the evaporator of the fridge or the freezer. The controlled temperature range should be between –30 to 0 °C. The range can be modified by changing the value of the resistor placed in
series with the NTC (see Appendix 1).
Its resistance value decreases, following an exponential variation, when the temperature increases. Then, to get back the temperature data, the MCU could use a numerical table. In the
THERM01EVAL board, a simple resistor has been added in series with the NTC in order to linearize its thermal response (refer to Appendix 1). Two advantages come from this choice:
– Memory area savings
– Easy way to measure the temperature (refer to Appendix 1).
Temperature regulation is performed by hysteresis control. The linear temperature information
is then simply compared to the voltage given by the "TEMP. ORDER" potentiometer. The hysteresis threshold can be changed by software (see Application Note AN1353).
2.2.2 Motor control
The motor is driven by two ACST6-7ST devices:
– Tr: "RUN" Switch, ON when the temperature is too high, OFF when the temperature is low
enough or when an overcurrent has been detected.
– Ts: "START" Switch, only ON for the first 0.5 seconds of each start-up, i.e. each time Tr is
switched ON. Ts can be not used (refer to Appendix 2). In this case, only Tr controls the motor.
Both ACSTs are turned on whenever a Zero Voltage Crossing (ZVC) event occurs. In order to
reduce the power supply rating, the ACSTs are triggered by a pulsed gate current.
2.2.3 Light bulb
A light bulb is driven by the ACS102-5T1 called "Tb". This device is ON or OFF when the
"DOORSWITCH" is opened or closed respectively. Instead of using the switch on the board
(S1), you can connect an external switch via the "DOOR" connector.
The ACS is turned on whenever a ZVC event occurs. In order to reduce the power supply
rating, the ACS is triggered by a pulsed gate current.
2.3 HARDWARE DESCRIPTION
2.3.1 ACS & ACST devices
The THERM01EVAL board has an on-board ACS102-5T1 plus two ACST6-7ST devices. The
datasheet of these devices can be found on the ST website (go to http://www.st.com/stonline/discretes/index.shtml and click on "Thyristors").
Table 1 sums up the main differences between ACS & ACST and traditional triacs.
8/20
FUNCTIONAL DESCRIPTION
Table 1. Differences between ACS/ACST and TRIACS
Parameter
(min)
VBR
(dV/dt)
(dI/dt) at turn-on
TRIAC
1 A / 5 mA
sensitivity
Destruction if
voltage > VBR
20 V/µs
10 A/µs
ACS102
0.2 A / 5 mA
sensitivity
Clamped at 600 V
300 V/µs
100 A/µs
TRIAC
6 A / 10 mA
sensitivity
ACST6
6 A / 10 mA
sensitivity
Destruction
Clamped at 900 V
if voltage > VBR
100 V/µs
200 V/µs
20 A/µs
100 A/µs
2.3.2 ST6200C Microcontroller
The MCU used in the THERM01EVAL board is the ST62T00C. It is a basic ST6 microcontroller that embeds a large number of features at minimum cost.
The peripheral hardware requirements have been reduced to the minimum:
– No quartz crystal or external resonator is used. In fact, the internal RC-oscillator of the
ST62T00C is used to generate the clock.
– No external RESET circuit is required, as the ST62T00C has an internal circuit.
When programming the MCU EPROM, you have to set the following three options:
– D1: Hardware Watchdog Activation (as it is not done by software)
– D6: RC network oscillator selection
– D8: Low Voltage Detection option (in order to start a RESET subroutine when the board is
plugged to the mains).
– The ST62T00C program memory size is 1024 bytes. The size of the implemented software
is 974 bytes. In order to test longer programs, the ST62X01C (with 2K bytes of program
memory) can be installed instead of the ST62X00C in the DIL16 socket.
– Unused memory space must be filled with a NOP instruction (04H). The three last bytes
must be filled with: "0D D8 01" (hex.), in order to generate a RESET if the PC points to
unused locations.
2.3.3 Capacitive power supply
In order to reduce the board price as much as possible, a capacitive power supply is used on
the board instead of a transformer-based supply. This supply can only source an average current lower than 10 mA. For higher current the C1 capacitor (see Appendix 3) can be replaced
by one with a higher value.
One particularity of this power supply is to be a "negative" one. Indeed, the V DD terminal is
connected to Neutral. This means that the V SS voltage is 5V below Neutral. This type of connection is mandatory when the MCU drives ACS devices directly. In fact, ACSs can only be
triggered by a negative current (i.e. sourced from the gate).
9/20
USING THE EVALUATION BOARD
3 USING THE EVALUATION BOARD
3.1 CURRENT LOADS
Initially, there is no heat sink mounted on the TO220-AB of the ACST6-7ST devices. In this
case, Figure 2-2 of their datasheet shows that the maximum permanent allowed current is 1.5
A RMS, for an ambient temperature of under 40 °C. If the RUN triac has to sink a higher current, or work at a higher temperature, a heat sink can be added.
As the START triac works for a short time only, no heat sink is normally required. For example,
reliability tests have shown that ACST6-7ST can withstand 11 A RMS for half a second, for
more than 300 k cycles (refer also to AN1354).
The ACS102-5T1, which has an SO8 package, can withstand a 0.2 A RMS permanent current
in an ambient temperature of up 90 °C. And this is reached with a very low copper area on the
COM terminals (approx. 2 mm²). Based on this information, we can assume that the ACS1025T1 can drive the common types of light bulb found in fridges or freezers without any problem.
In fact, a 25 W bulb will always sink a current lower than 150 mA.
3.2 CONTROL PULSES
Figure 2 shows how the gate current pulses are defined, for the two loads. The choice of these
durations is explained in Application Note AN1354.
If the loads used sink a different current, or with a different power factor, there is the risk of
missing firing the triac for one or several half cycles. So you should check that the programmed angles are compatible with the loads connected to the board. If not, refer to AN1353
and AN1354 to change these values.
10/20
USING THE EVALUATION BOARD
Figure 2. Gate current pulses
NMI
Vmains
PA3
(ACS102 control)
PA1/2
(ACST6 control)
3.3 OVERCURRENT DETECTION
The overcurrent detection is active one second after motor start-up. This delay is needed to
differentiate a start-up transient current from a real overcurrent caused by a stalled rotor. After
an overcurrent detection, the D1 LED is switched on for 10 seconds.
The overcurrent is detected by measuring the RUN current through the 0.05 Ω shunt resistor
(R10 in Appendix 3). Each measurement is performed approximately 7 ms after ZCS, when
the V LN voltage is negative. If the current peaks at a different time, this delay can be changed
by software (see AN1353).
The overcurrent detection is based on an average of four measurements, in order to reduce
measurement noise. The motor will then be stopped at least 80 ms after an overcurrent has
appeared.
3.4 MEASUREMENT POINTS
Figures 3 and 4 show where the V DD and V SS planes are placed and also the measurement
points that can be used.
11/20
CONCLUSION
Figure 3. Top layer view (from component side)
VSS plane
VSS measurement point
VDD measurement
point
VL measurement point
VN measurement
point
Figure 4. Bottom layer view (from component side)
V SS plane
V DD plane
4 CONCLUSION
The g uide lin es pro vided in this do cum ent ha ve bee n given t o help you u se the
THERM01EVAL board properly. The board is designed for conventional monophase induction
motors in fridge and freezer applications (especially for 1/5 horse-power compressors).
The main thing to check is that your loads, especially the compressor load, correspond to programmed data (pulse, delay for detecting the overcurrent, etc.). Then, after some adjustment
to your software (and using the EPROM version of the ST6200 MCU), you can perform tests
with a freezing system. One interesting measurement to carry out would be to see how much
the temperature regulation is improved and how much the power consumption is reduced by
removing the PTC and decreasing the motor operation duty cycle.
Information on these two last points is also given in Application Note AN1354.
12/20
CONCLUSION
Appendix 1 – Thermal Sensor Linearization
A NTC thermistor is a resistor whose value decreases when its temperature increases. The
thermal law is exponential, as presented in Equation 1.
Equation 1:
Rc(T) =
1
Ro. exp B.
T
1
To
To build a simple voltage sensor, it is better to linearize the temperature response using a constant resistor (R1) added in series with the NTC (Rc). This creates a voltage divider. The
voltage across R1 will follow the supply voltage (VDD ) according to the relationship below:
Equation 2:
Rc ( T)
Vs = ----------------------------- ⋅ V D D
R c( T) + R1
To make the relationship of Equation 2 to vary linearly, it's enough to ensure that the second
order derivative will be zero. Equation 3 gives the R1 value to ensure this condition.
d
Rc( T )
2.
dT
Equation 3:
R1 =
d
2
Rc( T )
2
Rc( T )
d T2
To linearize the voltage response of a M2020 12 k from EPCOS, between –30 and –5 °C, a 62
k Ω resistor should be chosen for R1. In this temperature range, Vs varies according to Equation 4, for a 5 V supply:
Equation 4:
Vs(T) = (T+50.1)/15.625
Figure 5 gives the variation of Vs and the linear value given by Equation 4 (refer to Vl), versus
the temperature sensed by the CTN.
13/20
CONCLUSION
Figure 5. Linear voltage response of the NTC resistor (for a 5 V supply)
5
4
3
Vs
Vl
(V)
2
1
0
-40
-30
-20
-10
T (°C)
14/20
0
10
20
CONCLUSION
Appendix 2 – Wiring connections
For the NTC, you only have to cut its connector (standard connector for M2020 sensors) and
to screw the wires in the "NTC" connector. It can be connected in both ways as it is just a resistor. For the motor, things are more complex.
Figure 6 shows how the wires are generally accessible in compressor motors. These three
pins may be connected directly to the THERM01EVAL connector.
Figure 6. Compressor connections
LINE
RUN
START
Often, compressor motors are used with a starter that includes a thermal protection against
excessively high currents or overheating. This protection is called a "klixon", and is shown in
Figure 7. When you are using the THERM01EVAL board its better to keep this starter, in order
to let the klixon work. In this case, the motor connections can still be accessible, this depends
on the starter model, as shown in Figure 7.
15/20
CONCLUSION
Figure 7. Compressor starter
LINE
Klixon
PTC
RUN
START
If you want to keep the PTC acting inside the starter, then the RUN pin must not be connected
to the "RUN" connector of the THERM01EVAL board.
If you remove the PTC, it is better to put an insulation layer in its place, in order to avoid spurious short-circuits between the RUN and START windings.
16/20
3
2
1
MAINS
J5
N
L
FUSE 6 A / 250 V
F1
C4
10 nF X2
R11
47R 1/2 W
D2
6V2 1.3W
C1
470nF X2
D3
C2
100nF
C3
2200µF / 10 V
C11
680pF
R6
470K
+
R9
47K
C12
1 µF
Vdd
1
4
6
5
2
3
ST62T00C
VDD
NMI
RST
VPP/TEST
OSCIN
OSCOUT
U1
VSS
PB6/AIN
PB7/AIN
PB5/AIN
PB0/AIN
PB1/AIN
PB3/AIN
PA1
PA2
PA3
16
8
7
9
12
11
10
15
14
13
C7
1
2.2nF
2
3
POT A
100K
S2
C8
2.2nF
R8
62K
R12
1K
R5
1.5K
R7 33k
R4
360R
R3
160R
R2
160R
C9
doorswitch
2.2nF
C10
2.2nF
C5
1nF
R13
51R
2
1
DOOR
1
2
J3
NTC
1
2
J2
D1
LED
Ts
Start ACST6
BULB
J1
R10
50m 1/2 W
Vdd
Tb
Bulb ACS102
Tr
Run ACST6
R1
33R 1/2W
L_PCB
6µH
Start
C6
1nF
R14
51R
MOTOR
1
2
3
J4
Run
L
CONCLUSION
Appendix 3 – THERM01EVAL Schematics
Figure 8. THERM01EVAL schematic
17/20
CONCLUSION
Appendix 4 – Bill of Materials
N°
R1
R2 / R3
R4
R5
R6
R7
R8
R9
R10
R11
R12
R13
R14
C1
C2
C3
C4
C5 / C6
C7 / C8 / C9 /
C10
C11
C12
F1
S1
POT
D1
D2
D3
TS
TR
TB
U1
18/20
DESCRIPTION
Resistor ½ W Through_Hole 33 Ω hm 5%
Resistor 1/8 W SMD 160 Ωhm 5% 0805
Resistor 1/8 W SMD 360 Ωhm 5% 0805
Resistor 1/8 W SMD 1.5 K Ωhm 5% 0805
Resistor 1/4 W Through_Hole 470 K Ω hm 5%
Resistor 1/8 W SMD 33 KΩ hm 5% 0805
Resistor 1/8 W SMD 62 k Ωhm 5% 0805
Resistor 1/8 W SMD 47 KΩ hm 5% 0805
Resistor ½ W Through_Hole 0.05 Ωhm 5%
Resistor ½ W Through_Hole 47 Ω hm 5%
Resistor 1/8 W SMD 1 K Ωhm 5% 0805
Resistor 1/8 W SMD 51 Ω hm 5% 0805
Resistor 1/8 W SMD 51 Ω hm 5% 0805
Cond. 250 V X2 470 nF 20% (Ref. EPCOS: B81130C1474M)
Cond. SMD 6V3 100 nF
Cond. Radial 10 V 2200 µF 20% (Ref. EPCOS: B41821A3228-M)
Cond. 250 V X2 10 nF 20% (Ref. EPCOS: B81130C1103M)
Cond. 250 VAC 1 nF 20%
Cond. SMD 6V3 2.2 nF
Cond. SMD 6V3 680 pF
Cond. SMD 10V 1 µF 1206
Fuse 5x20 mm 6 A 250 V
Switch
Potentiometer Single-Turn 100 K
Red LED / diameter: 5 mm / 5 V / 2 mA
Zener 6V2 1.3 W SMD
Rectifier 1N4148 SMD
ASCT6-7ST (TO220)
ASCT6-7ST (TO220)
ASC102-5T1 (SO8)
Microcontroller ST62T00C (DIP16 – Through Hole)
CONCLUSION
Appendix 5 – Procedure for IEC61000-4-4 Voltage Burst Test
Fast transient voltage tests have been performed, according to the EN61000-4-4 standard, on
THERM01EVAL boards connected to a compressor and three 25 W light bulbs. One of these
bulbs is the fridge internal lamp. The two other ones are placed in parallel with the motor windings. This enables any spurious device firing to be easily detected. In fact, as soon as one
switch conducts a few milliseconds, the bulb will emit some light.
The test layout, shown on Figure 9, have been done in order to implement very high stress
tests, but still in accordance with the EN61000-4-4 standard. The main characteristics of the
setup are:
THERM01EVAL Board, loads and mains wires are placed 10 cm above the ground
reference.
The mains wire is shorter than 1 m.
The compressor protective earth is linked to the PE of the board through a 30 cm cable.
Each operating cycle has been tested (all loads OFF, lamp ON, Motor ON, lamp + motor ON).
The burst withstanding level is in the range of 3 to more than 4.5 kV (maximum generator capability), depending on the coupling mode (to L, N, PE, etc.).
Figure 9. EN61000-4-4
test layout
PE
connector
10 cm
Bursts
generator
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CONCLUSION
Notes:
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