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 2.sup.N-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.