SG6105A

SG6105A — Power Supply Supervisor+Regulator+PWM July 2009 SG6105A Power Supply Supervisor + Regulator + PWM Features ƒ ƒ ƒ ƒ ƒ ƒ ƒ ƒ ƒ ƒ ƒ ƒ ƒ ƒ ƒ PC Half-Bridge (or 494) Power Supply Supervisor + two 431 + PWM High Integration with 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 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, whi...