A reverse-voltage protection circuit for MOSFET power switches

摘要

When MOSFET is used as a power switch, it is essential to preventnreverse current flow through the parasitic body diodes under reversenvoltage condition. A new built-in reverse voltage protection circuit fornMOSFETs has been developed. In this design, an area-efficient circuit isnused to automatically select the proper well bias voltage to preventnreverse current under the reverse-voltage condition. This built-innreverse protection circuit has been successfully implemented in anhigh-side power switch application using a 0.6-Μm CMOS process. Thendie area of the protection circuit is only 2.63% of that of a MOSFET.nThe latch-up immunity is greater than +12 V and -10 V in voltagentriggering mode, and greater than ±500 mA in current triggeringnmode. The protection circuit is not in series with the MOSFET switch, sonthat the full output swing and high power efficiency are achieved