TinySwitch™-II integrates a 700V power MOSFET, oscillator, high voltage switched current source, current limit and thermal shutdown circuitry onto a monolithic device. The start-up and operating power are derived directly from the voltage on DRAIN pin, eliminating the need for a bias winding and associated circuitry. In addition, the TinySwitch-II devices incorporate auto-restart, line undervoltage sense, and frequency jittering. An innovative design minimizes audio frequency components in the simple ON/OFF control scheme to practically eliminate audible noise with standard taped/varnished transformer construction. High voltage powered-ideal for charger applications. High bandwidth provides fast turn on with no overshoot and current limit operation rejects line frequency ripple. Built-in current limit and thermal protection improves safety and ideal for cell-phone charger and PC standby applications. Simple design practically eliminates rework in manufacturing.