Converter IC Replaces Linear Transformers

Designers of chargers and adapters delivering less than 4W will be able to eliminate the bulky, power-hungry linear transformer commonly found in these units with the LNK520 power-converter chip. The device, which requires just three terminals, integrates a 700V power MOSFET and PWM controller with high-voltage startup, current limiting, and thermal shutdown circuitry onto a CMOS chip. The chip also includes auto-restart for short-circuit and open-loop fault protection, and it employs the company's EcoSmart technology, which promises to significantly reduce energy consumption during standby and no-load conditions. Obtainable from the company's web site, design support includes a 20-page data sheet, design guide application note (AN-35), design idea circuit (DI-75), and the PI Experta power supply design application. A design accelerator kit (DAK-54) containing two universal-input, 2.75W ac/dc adapters, product samples, an engineering report, and other collateral is also available. In a plastic DIP-8, price for the LNK520P is $0.35 each/10,000. The DAK-54 costs $19.95. POWER INTEGRATIONS, San Jose, CA. (408) 414-9665.