Power conversion IC reduces system cost

TinySwitch-III looks well suited for use in a wide variety of power supply applications including DVD players, white goods, industrial controls, chargers for portable electronics, and standby power for PCs, servers and LCD TVs. A high level of integration enables simple, flexible designs with far fewer components than competing discrete and integrated solutions.

It features a 700V MOSFET alongside low-voltage control circuitry on a monolithic IC. Other features include integrated auto-restart, input under-voltage and output over-voltage protection, hysteretic thermal shutdown, and frequency jittering to minimize EMI.

Application flexibility is increased through the use of selectable current limits, allowing designers to choose any of three current limit values for each family member without any additional IC pins or external components.

TinySwitch-III employs an ON/OFF control scheme, which delivers virtually constant efficiency regardless of load - a key advantage with respect to recent efficiency standards for external power supplies which specify an average efficiency across a range of load levels. By contrast, PWM and self-oscillating designs exhibit diminishing efficiency as load decreases. TinySwitch-III also enables easy compliance with the most stringent standards for standby and no-load energy use, consuming less than 150mW of no-load power without the use of a bias winding on the transformer.

The new device is available in lead-free, plastic through-hole DIP-8 and surface-mountable SMD-8 packages. Pricing in 1000-piece quantities for the TNY274PN, a 6W part in a DIP-8 package, is $0.79 each. The TNY280PN, a 28 W part, is priced at $1.45 each.