SG6108 Datasheet, PDF (1/16 Pages) Fairchild Semiconductor – Power Supply Supervisor + PWM

Power Supply Supervisor + PWM
Product Specification
SG6108
FEATURES
„ PC half-bridge (or 494) power supply supervisor +
PWM
„ Highly Integrated and Few external components
required
„ Over voltage protection 3.3V/5V/12V (two 12V)
„ Under voltage protection 3.3V/5V/12V (two 12V)
„ Under voltage protection for –12V and/or –5V
„ Over current protection 3.3V/5V/12V (two 12V)
„ Over power protection
„ Short circuit protection
„ Power-down warning circuitry
„ Power good circuitry
„ Delay time for PSON and PG signals
„ Remote ON/OFF function
„ On-Chip oscillator and Error amplifier
„ Latching PWM for cycle-by-cycle switching
„ Soft-start
„ Maximum 48% duty cycle
APPLICATIONS
Switching mode power supplies for computers such
as ATX, NLX, and SFX (micro-ATX).
DESCRIPTION
The SG6108 controller is designed for desktop PC
switching mode power supplies. It provides everything
necessary to monitor and control the output of the power
supply. Remote ON/OFF control, power good circuitry,
over-voltage protection, over-power protection, and
over-current protection are all included. The SG6108
directly senses all the output rails for over voltage
conditions without requiring external dividers. An
innovative AC-signal sampling circuit provides an
adequate power-down warning signal for PG. A built-in
timer generates accurate timing for the control circuit.
Cycle-by-cycle PWM switching protects the power
transformer from saturation and ensures a rapid response
for short-circuit protection. This greatly reduces the stress
on the power transistors. The SG6108 utilizes a minimum
number of external components while including all the
functions needed for push-pull and/or half-bridge
topologies. This decreases production costs and PCB
space while increasing the power supply’s MTBF.
TYPICAL APPLICATION
Main Transformer
5Vsb
Pok
Pson
Vdd
+
+
+
+
SG6108
UVAC IS12
IS5
Vcc
IS33
V33
V5
PG
V12
Pson
VS12B
OP1
NVP
RI
GND
IN
COMP
OP2
SS
OPP
+
12V
-12V
+
12V
+
5V
+
3.3V
-12V
-5V
5V
12V
© System General Corp.
Version 1.0.1 (IAO33.0048.B0)
-1-
www.sg.com.tw • www.fairchildsemi.com
September 26, 2007