STMicroelectronics UC3843BN, PWM Controller, 500 kHz 8-Pin, PDIP

Pulse-width modulator (PWM) controllers can support isolated and non-isolated AC-DC and DC-DC switch mode power supplies. They are based on the most popular topologies in both single-ended, such as fly-back, forward or quasi-resonant controllers, and double-ended configurations, such as asymmetrical half-bridge, for Switch Mode Power Supplies (SMPS).
The PMW controllers also integrate a comprehensive set of protections for enhanced robustness and reliability.

PWM (Pulse Width Modulation) Controllers, STMicroelectronics