EDN — 05.23.96 Regulator IC controls multiple outputs<

Out in Front: May 23, 1996

Regulator IC controls multiple outputs

The trend toward innovative dc/dc power-related ICs continues with Cherry Semiconductor's introduction of the CS-5101 secondary-side post-regulator. Designed for loads from 50W to several hundred watts, this IC develops two or more supply rails with 1 to 2% regulation. The 400-kHz device can replace the magnetic amplifiers this power range often requires; such amplifiers cannot operate at bandwidths higher than 200 kHz and perform poorly when idling with loads that are small compared to the maximum rating.

The CS-5101 controls switching of an external power FET, using PWM to establish the output voltage. It offers lossless switching by sensing when current and voltage are absent in the turn-off pulse and regulates efficiently from no-load through full-load conditions. In addition to an internal reference with 2% accuracy, the IC includes an undervoltage lockout, which inhibits operation until at least 8V is present at the IC's input; a FET drain-voltage monitor to keep the IC off when the supply is lower than minimum; sleep-mode operation to minimize quiescent power consumption; and frequency synchronization, so that you can operate multiple CS-5101s simultaneously. The IC is available in 14-lead plastic DIP and 16-lead SOIC packages; each measures 300 mils wide. Price is $3.76 (10,000).

—by Bill Schweber

Cherry Semiconductor Corp, East Greenwich, RI. (800) 272-3601, fax (401) 885-5786, info@cherry-semi.com.