LM1577/LM2577 are monolithic integrated circuits that provide all of the power and control functions for step-up (boost), flyback, and forward converter switching regulators. The device is available in three different output voltage versions: 12V, 15V, and adjustable. Requiring a minimum number of external components, these regulators are cost effective, and simple to use. Features include NPN output switches, wide input voltage range, current-mode operation, 52 kHz internal oscillator, soft-start function, and output switch protection.