A 20-V CMOS-Based Monolithic Bidirectional Power Switch

Bidirectional power-switching devices are needed in many power-management applications, particularly in lithium-ion battery protection circuitry. In this letter, a monolithic planar bidirectional power switch fabricated with a simplified CMOS technology is introduced. The new four-terminal device provides a blocking voltage greater than 20 V and a low on-resistance in either direction between its two power terminals. Detailed device characterization and analysis reveal that the new device structure has good latch-up immunity even though it comprises several p-n junctions in close proximity. This new CMOS-compatible power switch can be used in discrete form or as part of a power IC