Rohm BD7F205EFJ-C User manual

1/25
© 2022 ROHM Co., Ltd.
65UG028E Rev.001
2022.7
User's Guide
Figure 1. BD7F205EFJ-EVK-001
Isolated DC/DC Converters ICs
Built-in Automotive Switching MOSFET
Isolated Flyback Converter ICs
BD7F205EFJ-C Evaluation Board
BD7F205EFJ-EVK-001
Overview
This evaluation board outputs an isolated 6.2 V, 16.5 V and 6.2 V voltage from an input of 8 V to 32 V, and can output a maximum
output power 6 W.
BD7F205EFJ-C is an isolated flyback converter that does not require a photocoupler.
Feedback circuit by the transformer’s tertiary winding or photocouplers becomes unnecessary, contributing to reduction of set
parts.
It also has a number of built-in protection functions that enable the design of isolated power supply applications for high reliability.

2/25
© 2022 ROHM Co., Ltd.
65UG028E Rev.001
2022.7
User's Guide
Performance Specifications
This is a typical value and does not guarantee the characteristics.
Unless otherwise specified, VIN = 12 V, IOUT = 0.1 A, Ta = 25 °C
Parameter
Symbol
Min
Typ
Max
Units
Conditions
Input voltage range
VIN
8
12
32
V
Output voltage 1
VOUT1
5.5
6.2
6.9
V
IOUT1 = 0.1 A
Output voltage 2
VOUT2
14.8
16.5
18.2
V
IOUT2 = 0.1 A
Output voltage 3
VOUT3
5.5
6.2
6.9
V
IOUT3 = 0.1 A
Output current 1
IOUT1
0
0.3
A
Output current 2
IOUT2
0
0.1
A
Output current 3
IOUT3
0
0.3
A
Maximum output power
POUT
-
-
6
W
Standby power
PINSTBY
-
40
100
mW
IOUT = 0 A VIN = 12 V
Power Supply Efficiency
η
60
75
-
%
POUT = 2 W

3/25
© 2022 ROHM Co., Ltd.
65UG028E Rev.001
2022.7
User's Guide
BD7F105EFJ-EVK-001
Figure 2. Connection Diagram
Operating Procedure
1. Necessary equipment
(1) DC power supply of V to 32 V, 10 W / 5 A or more
(2) Load device up to 5 W
(3) DC voltmeter
2. Connecting the Equipment
(1) Preset the DC power supply to 8 V to 32 V and turn off the power output.
(2) Set the load to less than or equal to the rated current of each output and disable the load.
(3) Connect the positive terminal of the power supply to the VIN terminal and the negative terminal to the GND
terminal with a pair of wires.
(4) Connect the positive terminal of the load to VOUT terminal and the negative terminal to GND terminal with a
pair of wires.
(5) When connecting a wattmeter, connect as shown below. (Refer to your power meter User's Manual for more
information)
(6) Connect the positive terminal of the DC voltmeter to VOUT terminal and the negative terminal to GND terminal
for measuring the output voltage.
(7) Turn on the output of the DC power supply.
(8) Check that the DC voltmeter display is at the set voltage.
(9) Activates the load.

4/25
© 2022 ROHM Co., Ltd.
65UG028E Rev.001
2022.7
User's Guide
BD7F105EFJ-EVK-001
Figure 3. Circuit diagram
Application circuit
The evaluation board operates with an average frequency of approximately 363 kHz.
Monitoring the flyback voltage due to the voltage at the output provides primary-side feedback control that eliminates the
need for photocouplers and auxiliary windings.
Operation starts when the VIN pin voltage exceeds UVLO detect voltage of 3.4 V (Typ) and SDXEN pin Enable pin voltage of
2.0 V (Typ).
The circuit diagram of the demonstration board is shown in the figure below, and the parts list is shown on page 12.

5/25
© 2022 ROHM Co., Ltd.
65UG028E Rev.001
2022.7
User's Guide
BD7F105EFJ-EVK-001
1
2
3
4
8
7
6
5
GND
SDX/EN
L_COMP
REF
VIN
SW
N.C.
FB
EXP-PAD
(TOP VIEW)
Figure 4. Pin layout drawing
Outline of BD7F205EFJ-C
Features
◼AEC-Q100 (Grade-1)
◼No Need for Optocoupler and Third Winding of
Transformer
◼Output voltage is set by two external resistors and
transformer winding ratio.
◼Uses proprietary adaptive ON-time control
technology
◼Highly efficient light load mode (PFM operation)
◼Shutdown and Enable control
◼Burst voltage design possible
◼60 V Built-in-switching MOSFET
◼Spread frequency spectrum
◼Soft start function
◼Load current compensation function
◼Various protection functions
Undervoltage protection (UVLO)
Overcurrent protection (OCP)
Overheat protection (TSD)
REF pin open protection (REFOPEN)
Short-circuit protection (SCP)
Battery short-circuit protection (BSP)
Critical Characteristics
◼Input voltage range :
VIN terminal 3.4 V to 42.0 V
SW pin to 60 V
◼Switching frequency : 363 kHz (Typ)
◼Reference voltage accuracy: ±2.8 % (Typ)
◼Shutdown current 0 μA (Typ)
◼Operating temperature range -40 °C to +125 °C
Package W (Typ) x D (Typ) x H (Max)
HTSOP-J8 4.9 mm x 6.0 mm x 1.0 mm
Applications
Insulated power supply for automotive use (E-Comp, Inverter
etc)
Insulated power supply for industrial equipment
Pin Layout
PIN ASSIGNMENT
No.
Pin name
Function
1
GND
GND terminal
2
SDX/EN
Shutdown/Enable control pin
3
L_COMP
Load current compensation value setting pin
4
REF
Output voltage setting pin
5
FB
Output voltage setting pin
6
N.C.
No Connect
7
SW
Switching output pin
8
VIN
Power input terminal
-
EXP-PAD
Rear heat dissipation pin

6/25
© 2022 ROHM Co., Ltd.
65UG028E Rev.001
2022.7
User's Guide
BD7F105EFJ-EVK-001
Figure 5. Output Voltage1 vs Output Current1
IOUT2=30mA, IOUT3=50mA
Figure 6. Output Voltage2 vs Output Current1
IOUT2=30mA, IOUT3=50mA
Figure 7. Output Voltage3 vs Output Current1
IOUT2=30mA, IOUT3=50mA
Figure 8. Efficiency vs Output Current1
IOUT2=30mA, IOUT3=50mA
Measurement data
1. Load regulation
5.2
5.6
6.0
6.4
6.8
7.2
7.6
0 0.1 0.2 0.3
VOUT3[V]
IOUT1[A]
VIN=8V
VIN=12V
VIN=18V
VIN=32V
50.0
55.0
60.0
65.0
70.0
75.0
80.0
85.0
90.0
0 0.1 0.2 0.3
Efficiency[%]
IOUT[A]
VIN=8V
VIN=12V
VIN=18V
VIN=32V

7/25
© 2022 ROHM Co., Ltd.
65UG028E Rev.001
2022.7
User's Guide
BD7F105EFJ-EVK-001
Figure 9. Output Voltage1 vs Output Current1
IOUT2=100mA, IOUT3=300mA
Figure 10. Output Voltage2 vs Output Current1
IOUT2=100mA, IOUT3=300mA
Figure 11. Output Voltage3 vs Output Current1
IOUT2=100mA, IOUT3=300mA
Figure 12. Efficiency vs Output Current1
IOUT2=100mA, IOUT3=300mA
Measured data-continued
5.2
5.6
6.0
6.4
6.8
7.2
7.6
0 0.1 0.2 0.3
VOUT1[V]
IOUT1[A]
VIN=8V
VIN=12V
VIN=18V
VIN=32V
15.0
15.5
16.0
16.5
17.0
17.5
18.0
18.5
19.0
0 0.1 0.2 0.3
VOUT2[V]
IOUT1[A]
VIN=8V
VIN=12V
VIN=18V
VIN=32V
5.2
5.6
6.0
6.4
6.8
7.2
7.6
0 0.1 0.2 0.3
VOUT3[V]
IOUT1[A]
VIN=8V
VIN=12V
VIN=18V
VIN=32V
50.0
55.0
60.0
65.0
70.0
75.0
80.0
85.0
90.0
0 0.1 0.2 0.3
Efficiency[%]
IOUT[A]
VIN=8V
VIN=12V
VIN=18V
VIN=32V

8/25
© 2022 ROHM Co., Ltd.
65UG028E Rev.001
2022.7
User's Guide
BD7F105EFJ-EVK-001
Figure 13. Output Voltage1 vs Input Voltage
IOUT1=100mA, IOUT2=100mA, IOUT3=300mA
Figure 14. Output Voltage2 vs Input Voltage
IOUT1=100mA, IOUT2=100mA, IOUT3=300mA
Figure 15. Output Voltage3 vs Input Voltage
IOUT1=100mA, IOUT2=100mA, IOUT3=300mA
Figure 16. Frequency vs Input Voltage
IOUT1=100mA, IOUT2=100mA, IOUT3=300mA
Measured data-continued
2. Line regulation
5.2
5.6
6.0
6.4
6.8
7.2
7.6
010 20 30 40
VOUT1[V]
VIN[V]
VOUT1
15.0
15.4
15.8
16.2
16.6
17.0
17.4
17.8
18.2
18.6
19.0
010 20 30 40
VOUT2[V]
VIN[V]
VOUT2
5.2
5.6
6.0
6.4
6.8
7.2
7.6
010 20 30 40
VOUT3[V]
VIN[V]
VOUT3
300
310
320
330
340
350
360
370
380
390
400
010 20 30 40
VOUT3[V]
VIN[V]
Freq

9/25
© 2022 ROHM Co., Ltd.
65UG028E Rev.001
2022.7
User's Guide
BD7F105EFJ-EVK-001
Figure 17. MOSFET Waveform
Vin = 12 V, IOUT1,3 = 0.1 A, IOUT2 = 0.05 A
Figure 18. MOSFET Waveform
Vin = 12 V, IOUT1,3 = 0.3 A, IOUT2 = 0.1 A
Figure 21. Output voltage ripple Waveform
VIN = 12 V / IO1,2,3=0.1, 0.05, 0.1 A
Figure 22. Output voltage ripple Waveform
VIN = 12 V / IO1,2,3=0.3, 0.1, 0.3 A
Measured data-continued
3. Switching waveform
4. Load response waveform
5. Output ripple voltage waveform
VSW (20V/div)
VOUT1 (10V/div)
VSW (20V/div)
VOUT1 (10V/div)
VOUT2 (10V/div)
VOUT3 (10V/div)
VOUT2 (10V/div)
VOUT3 (10V/div)
VSW (20V/div)
VSW (20V/div)
VOUT1 (1Vac/div)
VOUT2 (1Vac/div)
VOUT3 (1Vac/div)
IOUT1 (200mA/div)
Figure 19. Load response
Vin = 12 V, IOUT2 = 0.05 A, IOUT3 = 0.1 A
IOUT1 = 30 mA to 300 mA
VOUT2 (1Vac/div)
VOUT1 (1Vac/div)
VOUT3 (1Vac/div)
IOUT2 (200mA/div)
Figure 20. Load response
Vin = 12 V, IOUT1 = 0.1 A, IOUT3 = 0.1 A
IOUT2 = 10 mA to 100 mA
VOUT1 (50mVac/div)
VOUT2 (50mVac/div)
VOUT3 (50mVac/div)
VOUT1 (50mVac/div)
VOUT2 (50mVac/div)
VOUT3 (50mVac/div)
*This ripple is due to spread spectrum.

10/25
© 2022 ROHM Co., Ltd.
65UG028E Rev.001
2022.7
User's Guide
BD7F105EFJ-EVK-001
Figure 23. Start Up Waveform
Figure 24. Shut Down Waveform
Figure 25. VOUT Short Waveform
Vin = 8 V
Figure 26. VOUT Short Waveform (ZOOM)
Vin = 8 V
Figure 27. VOUT Short Waveform
Vin = 15 V
Figure 28. VOUT Short Waveform (ZOOM)
Vin = 15 V
Measured data-continued
6. Startup/stop waveform
7. Output short waveform
VSW (20V/div)
VSW (20V/div)
VOUT1 (10V/div)
VSW (20V/div)
VOUT1 (10V/div)
VIN (5V/div)
VIN (5V/div)
VIN (10V/div)
VSW (20V/div)
ISW (2A/div)
VOUT (20V/div)
VSW (20V/div)
VIN (10V/div)
ISW (2A/div)
10ms/div
500us/div
VIN (10V/div)
VSW (20V/div)
ISW (2A/div)
ISW (2A/div)
VSW (20V/div)
VIN (10V/div)
10ms/div
500us/div
VOUT2 (10V/div)
VOUT3 (10V/div)
VOUT3 (10V/div)
VOUT2 (10V/div)
VIN (10V/div)
VSW (20V/div)
ISW (2A/div)