Switching Power-Supply Chips

July 7, 2005
STR-A61xx are low-standby input-power SMPS primary switches in DIP-8 packages.

STR-W67xx are quasi-resonant topology ICs with low EMI noise and bottom-skip function.

The STR-A61xx Series are designed for output power up to 20 W at universal input or 24 W at 230-Vac input. An auto-standby function reduces input power to <50 mW at 230-Vac input by burst-mode operation. The entire system is stabilized by current-mode feedback and blanking. Features include overvoltage, overcurrent, overload, and thermal-shutdown protection, as well as an avalancheguaranteed MOSFET.

The STR-W67xx Series has a fully molded TO-220 package that holds the controller chip and MOSFET for output power up to 140 W at universal input, or 240 W at 230-Vac input. A bottom-skip function skips the first bottom of VDS and turns on the MOSFET at the second bottom point to minimize operational frequency increase at light output load. Two standby functions reduce input power under light output load conditions: an auto-burst mode internally triggers by sensing on-time and a manual standby mode is executed by clamping the secondary output.

Allegro MicroSystems Inc.
115 Northeast Cutoff
Worcester, MA 01606
(508) 853-5000

Voice your opinion!

To join the conversation, and become an exclusive member of Machine Design, create an account today!