Digital Like Short Circuit to Ground Protection for DC-DC Converter

摘要

An adaptive method to protect a DC to DC buck converter from destruction in the event of a short circuit to ground at the output is described. The short circuit protection method is small and inexpensive, and uses very low current, allowing the buck converter to remain active and protected, as it self regulates below an acceptable maximum peak current. Inductor current is sensed in the current-mode loop circuitry and an over-current comparator is used. A masking interval generator is required to mask false over-current triggers caused by converter switching-induced glitches. Simple logic is used to detect if the current-limit comparator indicates over-current at the end of the masking interval and to implement over-current pulse-skipping on genuine over-current detection.

主权项

1. A switching converter having short circuit protection, comprising:
a) an over-current comparator configured to detect an inductor current exceeding a current limit; b) a masking delay generator configured to mask information provided by said over-current comparator for a time period; c) short circuit detection logic configured to detect if said over-current comparator indicates an over-current condition after said time period; and d) a pulse skipper for skipping one or more pulses during said over-current condition.