Rohm BD7682FJ-EVK-301 User Manual
© 2017 ROHM Co., Ltd.
No. 60AP001E Rev.001
2017.4
User Guide
© 2018 ROHM Co., Ltd.
No. 60UG064E Rev.001
19 Feb 2018
High voltage input aux power supply ev. Board
1 – 1700V SiC MOSFET SCT2H12NZ
2 – Quasi-resonant controller BD7F682FJ-LB
Board dimensions 80mm x 80mm
1
2
D
sec
V
OUT
AC Filter
Diode
Bridge
L
prim
L
sec
L
aux
Brown
Out
Gate
V
CC
V
CC
Gate
I
sense
ZT
Feedback
I
sense
Feedback
BD7682FJ
Q1
D
aux
C
OSS
+
-
Optocoupler
V
DC
+
-
ZT
Mask
Param.
Description
Value
VIN
Input
voltage
210…480 VAC
300…to 900 VDC
V
OUT
Output
voltage
12 VDC ± 3%
P
OUT
Output
power
30 W @ V
IN.MIN
40 W @ V
IN.MAX
fsw
Switching
frequency
90..120 kHz
Table 1- main electrical parameters.
BD7682FJ-EVK-301 EV BOARD USER GUIDE
Figure 1 – Top and Bottom views
The AUX board is able to operate with both AC and DC input voltages. It is therefore possible to derive the power directly
from the grid or from the system DC link, e.g. after the PFC stage. In case of AC input, the accepted input voltage range
goes from 210 VAC to 480 VAC. In case of DC input, the input range goes from 300 VDC to 900 VDC. This board version “301”
mounts screw connections to facilitate the cabling to 3phase input or Vdc input. It is possible to remove the connectors
and use vertical mounting connectors as an example of module board for Aux power supply in a power system.
The simplified schematic of the AUX board is shown in Figure 2.
Figure 2 – Simplified schematic of the AUX board.
1/16
User Guide
BD7682FJ-EVK-301 EV BOARD
© 2018 ROHM Co., Ltd.
No. 60TRxxxJ Rev.001
No. 60UG064E Rev.001
19 Feb 2018
Contents
1 Board information ....................................................................................................................................... 3
1.1 Schematics........................................................................................................................................ 3
1.2 Flyback Transformer ........................................................................................................................... 3
2 Board usage............................................................................................................................................... 4
2.1 General information before cabling and powering the board: ................................................................... 4
2.2 Cabling ............................................................................................................................................. 5
2.2.1 3 Phase AC connections: ............................................................................................................... 5
2.2.2 DC connections: ........................................................................................................................... 5
2.3 Test points ........................................................................................................................................ 6
3 Implementation and practical tests with AUX Board ........................................................................................ 7
3.1 Operation at no load ........................................................................................................................... 7
3.2 Normal operation ............................................................................................................................... 8
3.3 Efficiency and temperature measurements ............................................................................................ 8
4 Summary ................................................................................................................................................ 10
5 References ............................................................................................................................................... 10
Appendix A. Transformer datasheet and pictures ................................................................................... 11
Appendix B. Bill of Materials ............................................................................................................... 12
Appendix C. AUX Board layout ............................................................................................................ 14
Appendix D. Alternative Start-up Circuitry ............................................................................................ 15
This evaluation board is intended for research and development and for expert use in the research and
development facility only. This board is not intended for use for volume production.
2/16
User Guide
BD7682FJ-EVK-301 EV BOARD
© 2018 ROHM Co., Ltd.
No. 60TRxxxJ Rev.001
No. 60UG064E Rev.001
19 Feb 2018
Parameter
Calculated
Transformer (E25)
Primary inductance
1.07 mH
0.95 mH ±10%
Leakage inductance
--
1% (9 µH)
Maximum primary current
0.86 A
1.5 A *
Turn-ratio primary to secondary
10
10 ± 1%
Turn-ratio secondary to auxiliary
1.92
2 ± 1%
Figure 3 - Full schematic of the AUX board
* Core saturation current
1 Board information
1.1 Schematics
Please refer to Appendix B for BOM, Appendix C for Layout and Appendix D for alternative startup circuit to improve
efficiency.
1.2 Flyback Transformer
A customized transformer manufactured by Würth Elektronik (www.we-online.com), has been designed.
It is possible to order and get all the information by contacting the producer referring code n. 750316318.
The datasheet of the transformer can be found in Appendix A.
The primary side is composed by two windings in series, while the secondary side has been implemented with two
windings in parallel. The half-windings are interposed, in order to reduce the leakage inductance around 1% of L
will impact the switching behavior of the MOSFET. In addition, the windings have been implemented with Litz wire to
reduce the losses due to skin effect.
. This
pri
Table 2 - Calculated parameters and characteristics of the used transformer.
3/16
User Guide
BD7682FJ-EVK-301 EV BOARD
© 2018 ROHM Co., Ltd.
No. 60TRxxxJ Rev.001
No. 60UG064E Rev.001
19 Feb 2018
2 Board usage
2.1 General information before cabling and powering the board:
- Check carefully that the input voltages are within the maximum input range in table 1.
- Double check the cabling before powering the board.
- This board is protected against overload and short circuit.
- Avoid any imperfect connection that can create sparks
- Check the isolation class and section of the cables.
- Apply all appropriate checks and precautions for use of a high voltage board.
- Refer to the notice at the end of this document for proper usage of this board.
- Only use in a technical environment by professionals trained to safely manage high voltage boards.
- This board is only for evaluation purposes and it’s not guaranteed for prolonged usage or usage
in any final product
4/16
User Guide
BD7682FJ-EVK-301 EV BOARD
© 2018 ROHM Co., Ltd.
No. 60TRxxxJ Rev.001
No. 60UG064E Rev.001
19 Feb 2018
Phase 1
Phase 2
Phase 3
Neutral
12Vdc To Load +
Volt Ref To Load -
400Vac to
480Vac 3 Phase
Input DC Voltage+
Input DC Voltage -
12Vdc To Load +
Volt Ref To Load -
2.2 Cabling
2.2.1 3 Phase AC connections:
The board can be connected directly to 3 Phase mains as for the below connection guide.
Figure 4 - 3Phase AC connection
2.2.2 DC connections:
If the board is connected to an DC source please follow the below connection guide
Figure 5 – DC Voltage input connection
Please note that the board mounts diodes for the possibility to be supplied by AC. Due to high voltage input compatibility
are used 2 diodes in series. To avoid the drop of diodes effect on functionalities (i.e. efficiency measurements) connect
directly to the positive of Capacitor C6 and negative of capacitor C8
5/16
User Guide
BD7682FJ-EVK-301 EV BOARD
© 2018 ROHM Co., Ltd.
No. 60TRxxxJ Rev.001
No. 60UG064E Rev.001
19 Feb 2018
Test Point
Signal***
TP1
Controller ZT pin
TP2
Controller FB pin
TP5
Controller OUT pin
TP7
Controller V
CC pin
TP8
Controller Brown-out pin
TP10
Board V
OUT
TP11
Trafo sec. terminal
TP13
Controller GND pin
TP16
Input voltage V
IN
TP18
Controller CS pin
Table 3 – Testing points in AUX board.
2.3 Test points
The AUX board contains several testing points, from which it is possible to observe the board operation. The test points
and the related signals are given in the following table.
6/16
Loading...