Datasheet
Internal FET Abnormality Detection Function
High Efficiency / Low Standby Power
2-Channel Secondary Side Synchronous
Rectification Control IC
BD85506F
General Description
Key Specifications
BD85506F is a 2-channel secondary side Synchronous
Rectification (SR) controller for LLC with enhanced
abnormality detection function on the secondary side.
This IC has a function to detect FET abnormalities such
as body diode rectification operation.
◼ Input Voltage Range:
5.0 V to 32 V
◼ Operating Circuit Current
(SW Stopped Mode):
◼ Standby Circuit Current:
◼ Drain Monitor Pin Absolute Voltage:
800 µA(Typ)
300 µA(Typ)
120 V(Max)
In addition, it incorporates a high-accuracy overvoltage
detection circuit, contributing to improved safety and
reduction of external components.
For efficiency, the OFF threshold voltage of the
synchronous rectifier FET can be adjusted with a resistor.
Moreover, by providing the Source monitor pin of each
FET, it is possible to monitor the voltage between Drain
and Source, and further improvement in efficiency is
possible.
◼ Operating Temperature Range: -40 °C to +105 °C
Package
W(Typ) x D(Typ) x H(Max)
8.70 mm x 6.20 mm x 1.71 mm
SOP14
In the burst operation at light load of the primary side
controller, the synchronous rectification operation is
automatically placed in the standby state, suppressing the
switching power and the circuit current of the IC itself and
reducing standby power consumption.
The built-in multipurpose comparator can also be used as
a low consumption shunt regulator in addition to the
abnormality detection comparator.
The operating power supply voltage ranges from 5.0 V to
32 V, covering various output voltage lineups.
Additionally, by adopting a process with a high withstand
voltage of 120 V(Max), it is possible to directly monitor the
Drain voltage.
Applications
Isolated LLC Type AC/DC Power Supply.
Adapter, TV, Printer, Office Equipment, etc.
Typical Application Circuits
Features
◼ Internal FET Abnormality Detection Function for
Secondary Side Synchronous Rectification.
◼ Internal Overvoltage Detection Circuit (OVP).
(Externally adjustable, high accuracy: 2 %)
◼ Efficiency Improvement by FET OFF Threshold
Voltage is Adjustable.
OUT
◼ Source of each FET can be individually monitored.
◼ Internal Standby Mode Automatic Determination
Function.
GND
◼ Internal Multipurpose Comparator. (It can also be
used as a shunt regulator)
◼ With the Slow Start Function, it is possible to set the
FET Abnormality Detection Function at startup and
the during the start of Switching Operation
◼ Wide Input Voltage Range 5.0 V to 32 V
◼ D1, D2 Pin 120 V (Max) Breakdown Voltage
◼ Flow Compatible SOP14 Package
(Remark) The values in the datasheet are typical unless otherwise specified.
FAIL
〇Product structure : Silicon monolithic integrated circuit 〇This product has no designed protection against radioactive rays.
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