[System General Corporation]

DESCRIPTION

This high-integrated PWM controller provides several special enhancements to satisfy the needs for low power standby and protection features. In standby mode, PWM frequency reduction is used to lower the power consumption and support a stable output voltage. Due to Bi-CMOS process, the SG6840 reduces start up and operation current to achieve a higher efficiency power conversion. Start-up current has been reduced to 30uA typical and operating current has been shrunk to 3mA. The SG6840 is a fixed frequency PWM controller in normal operation; its patented green-mode function will decrease the PWM frequency in response to the decrease of the load.

FEATURES OVERVIEW

●Green-mode PWM to support “Blue Angle”Norm

●Low start up current 30uA

●Low operation current 3mA

●Leading-edge blanking

●Built-in synchronized slope compensation

●Totem pole output includes soft driving

●Constant output power

●Current mode operation

●Cycle-by-cycle current limiting

●Under voltage lockout (UVLO)

●Short circuit protection

●Programmable over-temperature protection

●Few external components & low cost solution

APPLICATIONS

General-purpose switching mode power supplies and flyback power converters, and

  ●Power Adapter

  ●Open-frame SMPS

  ●Battery Charger Adapter