A 93.5% efficiency, 400-mA current-mode dc-dc buck converter with watchdog functions

A current-mode dc-dc buck converter was implemented in a standard 0.35- m 1-poly 6-metal 3.3-V CMOS technology. This paper proposes watchdog circuits in order to ensure the reliability and to improve the performance of dc-dc converters. The dc-dc converter systems can be protected from over-voltage, over-temperature, and over-current conditions. In addition to the protection from destructive conditions, a reversecurrent protection circuit is implemented to improve efficiency under light-load conditions. The maximum efficiency of the fabricated converter was 93.5%. The chip area is only 1.02 mm².