Featured Products Isolated Flyback Converters
Featured Products
Simplifies isolated power supply configuration
Isolated Flyback Converters
BD7Fxxx Series
• Original adaptive on-time control simplifies circuit design and
contributes to greater miniaturization
• No need for a photocoupler or auxiliary winding
• Built-in phase compensation eliminates the need for
compensation components
• Guaranteed long-term, stable supply-ideal for industrial equipment
HSON8
HTSOP-J8
Fewer External Components
NEW
従来フライバック電源IC使用時との比較
Conventional Flyback Converter Circuit
ROHM Flyback Converter Circuit Requires
No Photocoupler or Auxiliary Winding
VIN=24V
VOUT+
24VDC Flyback
VIN
S
D
C
VOUT-
VOUT+
VIN
New controller design
eliminates the need for
a photocoupler or
Auxiliary winding
VIN
EN/UVLO
VOUTRFB
SW
RCOMP
Simplified Circuit
AGND
PGND
RREF
BD7F100EFJ
• No photocoupler or transformer
tertiary winding required
• External phase compensation
unnecessary
• Built-in undervoltage lockout
(UVLO), overcurrent protection
(OCP), and thermal shutdown
(TSD) circuits
Load Compensation Function
Effects of Load Compensation
VIN
FB
5.25
SW
5.2
INTERNAL
REGULATOR
VREF
Output Voltage (V)
5.15
COMPARATOR
Shutdown
SDX/EN
Adaptive ON
Time Control
Circuit
VREF
Enable
VIN UVLO
SOFT
START
Nch
MOSFET
DRIVER
TSD
With load
compensation
5.1
5.05
Without load
compensation
5.0
4.95
4.9
Conditions
OCP
4.85
Load
Compensation
Circuit
VIN = 24V
VOUT = 5.0V
4.8
Current Monitor
4.75
0
AGND
REF
COMP
200
400
600
800
1000
Load Current (mA)
PGND
The built-in load compensation function corrects for
output voltage drop based on the VF characteristics of the
secondary SBD
(which is dependent on the load current)
Load Compensation
Setting Terminal
Isolated DC/DC Converter IC Lineup
Part No.
BD7F100HFN-LB
BD7F100EFJ-LB
BD7F200HFN-LB
BD7F200EFJ-LB
☆ BD7J100HFN-LB
☆ BD7J100EFJ-LB
☆ Under Development
Output Power
(W)
Input
Withstand
Voltage
(V)
1W (VIN =5.0V)
5W (VIN =24V)
45
1.25
10W (VIN =24V)
45
5W (VIN =48V)
80
Permissible
Input Voltage
Switch Current
Range
(A)
(V)
Switching
Frequency
(kHz)
Control
Method
3.0 to 40
400
2.75
8.0 to 40
0.65
6.0 to 80
Functions
Enable
Soft Start
Light Load
Efficiency
UVLO
Overcurrent
Protection
Thermal
Shutdown
Adaptive
on-time
✓
✓
✓
✓
Return
Return
400
Adaptive
on-time
✓
✓
✓
✓
Return
Return
400
Adaptive
on-time
✓
✓
✓
✓
Return
Return
Package
HSON8
HTSOP-J8
HSON8
HTSOP-J8
HSON8
HTSOP-J8
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