METHOD AND APPARATUS FOR OVERCURRENT PROTECTION IN DC-DC POWER CONVERTERS

摘要

A controller and method for a switched-mode power converter adaptively provides overcurrent protection by detecting a current in the power converter exceeding a current limit during substantially a minimum on time of a power switch. A count N is computed for the number of consecutive active switching cycles that a current exceeds a current limit during substantially the minimum on time of the power switch. Conduction of the power switch is inhibited for a number of cycles that is a function of the count N, which is an increasing function of N. The function of the count N is preferably the function 2N-1. The count N is reset to zero if the current in the power converter does not exceed the current limit substantially during the minimum on time of the power switch. The controller can be easily implemented with a digital integrated circuit for a wide range of applications.