Introduction
The highly integrated FSL-series consists of an integrated current-mode Pulse Width Modulator (PWM) and an avalanche-rugged 700V SenseFET. It is specifically designed for high-performance offline Switched Mode Power Supplies (SMPS) with minimal external components.

The features of the integrated PWM controller include a proprietary green-mode function providing off-time modulation to linearly decrease the switching frequency at light-load conditions to minimize standby power consumption. The PWM controller is manufactured using the BiCMOS process to further reduce power consumption. The green mode and burst mode functions with a low operating current (2mA in green mode) maximize light-load efficiency so that the power supply can meet stringent standby power regulations.