SG6203 Datasheet, PDF (1/13 Pages) Fairchild Semiconductor – Synchronous Rectifier Controller for Flyback Converter

Synchronous Rectifier Controller for Flyback Converter
Product Specification
SG6203
FEATURES
„ Low operation current (1.7mA)
„ One resistor for timing setting
„ Internal automatic tracking for optimum dead time
„ No reverse energy flow at light load
„ Best suited for primary green-mode PWM IC
„ Wide supply voltage range from 6V to 20V
„ Built-in 18V Zener diode
„ Optional current sensing:
- Current shunt
- RC network for better efficiency
APPLICATIONS
Flyback converters, such as:
„ Power adaptors
„ Open-frame SMPS
DESCRIPTION
The SG6203 is designed to control and drive the
synchronous rectifier for the flyback converter. The
synchronous signal of the primary switch is obtained by a
single diode connected between the transformer
secondary winding and the SG6203. Using the SG6203,
no additional transformer winding is required and the
circuit complexity can be minimized.
The power unit can be properly operated under
discontinuous conduction mode (DCM) or continuous
conduction mode (CCM). Problems such as
“shoot-through” or “cross conduction” in CCM and
energy-reverse from the secondary to the primary in DCM
are prevented by the SG6203 design.
TYPICAL APPLICATION
© System General Corp.
Version 1.0.1 (IAO33.0010.B1)
-1-
www.sg.com.tw • www.fairchildsemi.com
September 24, 2007