Duty cycle correction circuit

Abstract

A duty cycle correction circuit includes a duty adjustment circuit and a duty control circuit. The duty adjustment circuit generates a plurality of duty correction clock signals by adjusting phases of a plurality of external clock signals according to a plurality of codes. The duty control circuit controls a first correction operation of finding and fixing an optimal value of a first code among the plurality of codes and a second correction operation of finding and fixing an optimal value of a second code among the plurality of codes. The duty control circuit is configured to, in each of a plurality of cycles during which the first correction operation is performed, change the first code by a basic unit within a first adjustable range and change the second code by a maximum value within a second adjustable range.

Images