ST UM0527 User manual

July 2008 Rev 1 1/66
UM0527
User manual
UPS evaluation board
Introduction
The UPS evaluation board provides a complete solution addressing the low/medium range
UPS segment with 700 VA output power capability. The evaluation board, from a hardware
and firmware point of view, is ready to support the development of a complete solution.
Thanks to the PC software it's possible to monitor all the relevant system parameters using
the RS232 interface or the USB. The evaluation board is available for the 120 Vac market
and 230 Vac market.
The UPS evaluation board is built in offline topology with AVR regulation of the mains boost
and buck. The inverter module contains the push-pull DC/DC converter and the DC/AC
output full-bridge generating quasi-sine waveform.
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Contents UM0527
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Contents
1 General description . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5
1.1 Hardware architecture . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5
1.1.1 General realization . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5
1.1.2 Block diagram . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6
1.1.3 Detailed description of electronics . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 7
1.1.4 DC/DC converter module . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 7
1.1.5 DC/AC inverter module . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 9
1.1.6 Power switches . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 11
1.1.7 RFI/EMI filter . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 12
1.1.8 Charger AC/DC . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 13
1.1.9 Control unit . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 15
1.1.10 Power supply . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 17
1.1.11 Interface . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 19
1.1.12 Measurements: input voltage, input voltage phase, output current, inverter
output voltage, battery voltage . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 21
1.1.13 Battery overcurrent protection . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 22
1.1.14 Mains protection . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 22
1.1.15 UPS modes . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 22
1.1.16 Microcontroller IN/OUT signals . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 23
1.1.17 Signals functions table . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 24
1.1.18 Detailed description of mechanics . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 25
1.2 Software architecture . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 26
1.2.1 Data models . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 26
1.2.2 Protocols . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 26
1.2.3 System architecture . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 27
1.2.4 Main loop . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 27
1.2.5 ADC . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 29
1.2.6 Communication . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 30
1.2.7 SPI . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 30
1.2.8 Keyboard . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 30
1.2.9 LEDs . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 31
1.2.10 Charger . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 31
1.2.11 Inverter . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 32
2 Technical description . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 33

UM0527 Contents
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2.1 Circuit diagram . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 33
2.2 Layout . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 43
2.3 Assembly description . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 45
2.3.1 General . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 45
2.3.2 Electrical . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 46
2.3.3 Mechanical . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 46
2.4 Connectors . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 50
2.4.1 PCB: mains input . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 50
2.4.2 PCB: outlet output . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 50
2.4.3 PCB: AVR transformer . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 50
2.4.4 PCB: battery . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 51
2.4.5 PCB . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 51
2.4.6 PCB . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 51
2.4.7 PCB . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 51
2.5 Signalization description . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 52
2.5.1 Indicators . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 52
2.5.2 Sound alarms . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 52
2.6 Bill of material . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 52
2.6.1 Bill of material for 120 Vac version . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 52
2.6.2 Bill of material for 230 Vac version . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 58
3 Technical specifications . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 64
4 Revision history . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 65

List of figures UM0527
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List of figures
Figure 1. Block diagram . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6
Figure 2. DC/DC converter . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 7
Figure 3. DC/AC inverter . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 9
Figure 4. Power switches. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 11
Figure 5. RFI/EMI filter . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 12
Figure 6. AC/DC battery charger . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 13
Figure 7. Control unit . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 15
Figure 8. Power supply . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 17
Figure 9. Interface . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 19
Figure 10. Measurements: input voltage, input voltage phase, output current, inverter output
voltage, battery voltage. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 21
Figure 11. Battery overcurrent protection . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 22
Figure 12. Main flowchart. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 29
Figure 13. Circuit diagram . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 33
Figure 14. DC/AC inverter . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 34
Figure 15. DC/DC converter . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 35
Figure 16. Control unit . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 36
Figure 17. Power switches . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 37
Figure 18. AC/DC battery charger . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 38
Figure 19. PC interface stage . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 39
Figure 20. Power supply . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 40
Figure 21. Measurement stages . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 41
Figure 22. RFI/EMI filter . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 42
Figure 23. Battery overcurrent protection . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 42
Figure 24. Top view . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 43
Figure 25. Bottom view . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 44
Figure 26. Electrical connections . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 46
Figure 27. Mechanical view . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 46
Figure 28. UPS with assembled rear outlets . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 47
Figure 29. UPS with front button and indicators . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 47
Figure 30. UPS with batteries and battery fuse . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 47
Figure 31. UPS with battery fuse . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 48
Figure 32. UPS with AVR transformer . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 48
Figure 33. UPS with automatic fuse and power wires . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 48
Figure 34. UPS with motherboard . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 49
Figure 35. UPS fully assembled. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 49
Figure 36. UPS . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 50

UM0527 General description
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1 General description
1.1 Hardware architecture
1.1.1 General realization
The UPS evaluation board is built in offline topology with AVR regulation of the mains boost
and buck. The inverter module contains the push-pull DC/DC converter and the DC/AC
output full-bridge generating quasi-sine waveform. The battery charger module is connected
at the output of the UPS and it also has the function of taking over the reactive power which
is present on the inverter during battery operation with reactive - resistive load.
The microcontroller controls all UPS functions. It monitors the mains parameters in order to
ensure the proper level of the output voltage. The microcontroller measurement parameters
are input/output mains voltage and phase, output inverter voltage, battery voltage, output
current and output power. The UPS has a built-in RS232, joint signals and USB interfaces
(USB for RS232 converter).

General description UM0527
6/66
1.1.2 Block diagram
Figure 1. Block diagram
HVDC
INV_A INV_B
INV_OUT1
INV_OUT2
VDD
VDD GND
VDD
DC/AC Invverter
DCAC12st05v031.sch
HVDC
VAKK
VDD
SHD
VDCDC
GND
DC/DC converter
DCDC12st05v031.sch
VCC
BAT_LOW
ACF!
UPS_OFF!
USB_IN!
TXD
RXD
INP_LEV
PHASE
ACL!
ACH!
ACF
OUT_REL!
OUT_LEV
INV_A
INV_B
SHD
CHOFF
AKK_LEV
VCC
ON/OFF
SW_ONP
PWR_LEV
VDCDC
ACI!
GND
VCCPU
VCC
VCC
ACF1!
Microcontroller unit
Microcontroller12st05v031.sch
AC_IN1 AC_IN2
ACL!
ACH!
ACF
OUT_REL!
IOUT_2
IOUT_1
AC_1
AC_2
INV_OUT1
INV_OUT2
AC_IN2
AC_IN1
ACI!
GND
VPP
AC_IN1
AC_IN2
AC_1
AC_2
Power Relays Relays12st05v031.sch
AC_2
AC_1
VDD CHOFF
VBAT
VDD
+VOUT
GND
AC/DC Charger
ACDC12st05v031.sch
VCC
BAT_LOW
ACF!
UPS_OFF!
USB_IN!
TXD
RXD
GND
ACF1!
Inerface unit Interface12st05v031.sch
VDD VBAT +VOUT
AC_IN2
ON/OFF
SW_ONP
VCC
AC_IN1
GND
VPP
VCCPU
Power Supply
PowerSupply12st05v031.sch
IOUT_1
IOUT_2
PWR_LEV
GND
VCC
Output Current Measurement
OutputCurrent12st05v031.sch
VBAT
AKK_LEV
GND
VCC
Battery Voltage
BatteryVoltage12st05v031.sch
AC_2
AC_1
OUT_LEV
GND
Output Voltage Inverter
InverterVoltage12st05v031.sch
AC_IN1
AC_IN2
PHASE
VCC
GND
VDD
INP_LEV
Input Voltage & Phase Measurement
InputVoltage12st05v031.sch
AC_IN1 AC_IN2
EMI/RFI FILTER
RFIEMI12st05v031.sch
VBAT
VAKK GND
Battery Overcurrent Protection
BatOver12st05v031.sch
AVR TRAFO
INPUT
OUTPUT
LED INDICATIONS
BUTTON
FUSE
FUSE
VCC
BAT_LOW
ACF!
UPS_OFF!
USB_IN!
TXD
RXD
INP_LEV
PHASE
ACI!
ACF
ACL!
ACH!
OUT_REL!
OUT_LEV
INV_A
INV_B
VDCDC
SHD
CHOFF
VAKK
VBAT
AKK_LEV
VCC
ON/OFF
SW_ONP
PWR_LEV
+VOUT
VDDVDD
AC_IN2
AC_IN1
AC_1
AC_2
AC_1
AC_2
AC_IN1
AC_IN2
IOUT_1
IOUT_2
AC_IN1 AC_IN2
BATTERY
VDD
HVDC
GND
GND
GND
GND
GND
GND
GND
GND
GND GND
GND
GND
VCCPU
VCC
VDD
VCC
ACF1!

UM0527 General description
7/66
1.1.3 Detailed description of electronics
1.1.4 DC/DC converter module
Figure 2. DC/DC converter
R60 10R Q6
STP75NF75
GND
D26
STTH8R06D
D28
STTH8R06D
D25
STTH8R06D
D27
STTH8R06D
R53 22k
GND
VAKK
VAKK
R61 10R
Q7
STP75NF75
GND
R55 22k
GND
DC/DC CONVERTER
C64
3300uF/35V
GND
R59 10R R62 10R
Q8
STP75NF75
Q5
STP75NF75
R56 22k
GND
R54 22k
GND
GND GND
A
1
D
2
C B
12 11
TI1
TI700/24/1v01
C66
470uF/63V
GND
R35 1k 3W D29
STTH302S D30 STTH302S
C86
1nF 1kV
R66
330R 2W
C87 330nF
GND
R18
7.5k
GND
C34 1nF
C33
4.7nF
GND
R28 0R
OUT_B OUT_A
R19
100k
VDD
R31 36k
GND
Vref
16
Clock 4
Ct
5
Rt
6
Disch
7
Sync
3
ErrAmp+
2
ErrAmp-
1SoftStart 8
VCC 15
VC 13
ShutDown 10
GND
12
OutB 14
OutA 11
ErrAmpOut
9
U3 SG3525A
R17
33R
R36 3.3k
Vref
GND
Vref
R30 5.6k
GND
R70
200k
C67
10nF
GND
HVDC
SHD
VDCDC
L1 1.5uH / 10A L2 1.5uH / 10A
R71 200k
R32 390k C68
10nF
GND
GNDGND
R69 200k R68 200k
R29 6.8k
GND
R67
330R 2W
RAD10 Heatsink
RAD8 Heatsink RAD7 Heatsink
RAD9 Heatsink
RAD5 Heatsink RAD6 Heatsink
R341k 3W
U4 PDTC114ET
R33 47R C62
10uF/50V
C32
100uF/25V
C12
100nF
GND
GND
GND
C50 100pF
GND
C65
3300uF/35V
GND
C13
100nF
GND
C15
100nF
GND
C14
100nF
GND
TI700/24/2v01
0R
1.5nF 1kV
STTH803D
STTH803D
STTH803D
STTH803D
100k
100k
100k
100k
100k
30k
120Vac Model 230Vac Model
VDCDC
SHD
HVDC
VDDVDD
VAKKVAKK
GNDGND
C72 100nF
GND
C43
1nF
GND
1uF

General description UM0527
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The converter is based on push-pull topology. The PWM controller works in voltage mode.
The power components used for the low voltage side are switches 5 - 8 and a transformer.
The energy recovery circuit includes L1, D1, L2, D2, C1 and R1. It works as both a clamp
and a snubber. Power components on the secondary side are limited to rectifier diodes D3 -
D6 and a small voltage smoothing capacitor. The output voltage is limited with direct control
loop without insulation. An internal soft-start circuit is used to limit the voltage rise rate on
the output of the DC/AC converter. The soft-start circuit is controlled from the microcontroller
by an additional transistor. The PWM controller is powered from the main UPS power supply
section. The output converter voltage range is battery voltage dependent and has been set
to achieve maximum efficiency.
Table 1. DC/DC specification
DC/DC converter 120 Vac version 230 Vac version
Output voltage 130 – 190 V 250 - 360 V
Output power 450 W 450 W
Efficiency > 80% > 80%
Frequency 40 kHz ± 10% 40 kHz ± 10%
PWM controller U1 SG3525 SG3525
Power switches 5 – 8 STP75NF75 STP75NF75
Push-pull transformer T11 EE42 EE42
Rectifiers diodes D1 – D4 STTH803 STTH8R06

UM0527 General description
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1.1.5 DC/AC inverter module
Figure 3. DC/AC inverter
DC/AC INVERTER
HVDC
GND
D1 SMBYT01
VDD
R12 10k R11 10k
R7 100R
C1
10uF/25V
R14
10k
R13 10k
LIN
1HIN 2
VCC
3
GND
4
LVG 5
VO 6
HVG 7
VB 8
U1 L6387D
Q1 STP12NM50 Q2 STP12NM50 Q4
STP12NM50
Q3
STP12NM50
D2
SMBYT01
VDD
C2
10uF/25V
LIN 1
HIN 2
VCC 3
GND
4
LVG
5VO 6HVG 7VB 8
U2 L6387D
INV_B INV_A
INV_A INV_B
INV_OUT2
INV_OUT1
R1 100R R2 100R
C8
100nF
C10
100nF
C9
100nF
C11
100nF
GND GND
GND GND
R3 0R D3
BAS16
R8 100R
R4 51R D4
BAS16
R10 100R
R6 51R
D7
BAS16
R9 100R
R5 0R
D6
BAS16
ZD1
SM6T18A
D5
BAS16
ZD2
SM6T18A
D8 BAS16
STP22NS25Z STP22NS25Z STP22NS25Z STP22NS25Z
RAD1 Heatsink
RAD3 Heatsink
RAD2 Heatsink
RAD4 Heatsink
C4
10uF/35V
C3
10uF/35V
INV_A INV_B INV_A
INV_B
INV_OUT1
INV_OUT2
120Vac Model 230Vac Model
HVDC
GND
GND
HVDC
VDD VDD
R173 47R
R16410R
D47
STTH1L06A
D48 STTH1L06A
R174 47R
R172 10R
C36 100pF
GND
C35 100pF
GND
C39 100pF C40
100pF
GND
GND

General description UM0527
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The DC/AC inverter was built in full-bridge topology. The output waveform is a quasi-sine
waveform. The inverter is controlled by the microcontroller across two PWM drivers which
switch four power transistors. The high-side driver parts are supplied with the bootstrap
circuitry D1, C1 and D2, C2. The diodes D1 and D2 are high-voltage fast-recovery diodes.
Switching off all transistors is achieved with driver internal logic if both INV_A and INV_B
signals are set high or low. There is no any additional overcurrent protection for bridge
transistors. Drivers are powered from the main UPS supply unit.
Table 2. DC/AC specification
DC/AC inverter 120 Vac version 230 Vac version
Output voltage RMS 120 Vac +5%/ -10% 230 Vac +5%/ -10%
Frequency (microcontroller
outputs) 60 Hz ± 0.1 Hz 50 Hz ± 0.1Hz
Drivers U1, U2 L6387 L6387
Power switches Q1 – Q4 STP22NS25Z STP12NM50
Bootstrap diode D1, D2 SMBYT01-400 SMBYT01-400