Texas Instruments UCC3801D, PWM Controller, 1000 kHz 8-Pin, SOIC

The isolated-flyback power supply controller provides Constant-Voltage (CV) and Constant-Current (CC) output regulation to improve transient response to large load steps. Primary-Side Regulation (PSR) eliminates the need for an Optocoupler.

Flyback Controllers, Texas Instruments

Current-Mode and Voltage-Mode PWM Controller
Primary-Side Regulation
Peak Power Mode
Low Power