[System General Corp]

DESCRIPTION
SG6105 controller is designed for switching mode power supply 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, some protection features against over-voltage and over-power are implemented. It directly senses all the output rails for OVP without the need of external dividers. An innovated AC-signal sampling circuitry provides a sufficient power-down warning signal for PG. A built-in timer generates accuracy timing for control circuit including the PS-off delay. The cycle-by-cycle PWM switching prevents the power transformer from the saturation and ensures the fastest response for the short-circuit protection which greatly reduce the stress for power transistors. Two internal precision TL431 shunt regulators provide stable reference voltage and driver for 3.3V and 5V-standby regulation. Utilizing minimum number of external components, the SG6105 includes all of the functions for push-pull and/or half-bridge topology, decreasing the production cost and PCB space, and increasing the MTBF for power supply.

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 regulator 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, such as:
    ATX NLX SFX (micro-ATX)