SG6105A Datasheet, PDF (1/18 Pages) Fairchild Semiconductor – Power Supply Supervisor + Regulator + PWM

Power Supply Supervisor + Regulator + PWM
FEATURES
„ PC half-bridge (or 494) power supply supervisor +
two 431 + PWM
„ High integration & few external components
„ Over-voltage protection for 3.3V, 5V, and 12V
„ Under-voltage protection for 3.3V, 5V, and 12V
„ Under-voltage protection for –12V and/or –5V
„ Over-power and short-circuit protection
„ Power-down warning circuitry
„ Power-good circuitry
„ Delay time for PSON and PG signal
„ Remote ON/OFF function
„ On-chip oscillator and error amplifier
„ Two shunt regulators for 3.3V and 5V-standby
„ Latching PWM for cycle-by-cycle switching
„ Push-pull PWM operation and totem pole outputs
„ Soft-start and maximum 93% duty cycle
APPLICATIONS
Switching mode power supply for computers:
„ AT
„ NLX
„ SFX (micro-ATX)
Product Specification
SG6105A
DESCRIPTION
SG6105A controller is designed for switching-mode
power supplies for desktop PCs. It provides all the
functions necessary to monitor and control the output
of the power supply. Remote ON/OFF control,
power–good circuitry, and protection features against
over-voltage and over-power are implemented. It
directly senses all the output rails for OVP without
the need for external dividers. An innovative
AC-signal sampling circuitry provides a sufficient
power-down warning signal for PG.
A built-in timer generates accurate timing for the
control circuit, including the PS-off delay. The
cycle-by-cycle PWM switching prevents the power
transformer from saturation and ensures the fastest
response for the short-circuit protection, which
greatly reduces stress for power transistors. Two
internal precision TL431 shunt regulators provide
stable reference voltage and a driver for 3.3V and 5V
standby regulation.
Utilizing minimum external components, the
SG6105A includes the functions for push-pull and/or
half-bridge topology, decreasing production cost and
PCB space, and increasing the MTBF for power
supply.
© System General Corp.
Version 1.0.1 (IAO33.0072.B0)
-1-
www.sg.com.tw • www.fairchildsemi.com
September 25, 2007