DLL calibration method for fast frequency change without re-locking

摘要

A delay circuit includes a delay line configured to output an output signal by imposing a delay value on an input signal. The delay circuit further includes an arithmetic unit configured to calculate a control code for the delay value based on delay codes. The delay circuit further includes a delay locked loop (DLL) configured to generate the delay codes based on a clock signal. The delay circuit further includes a controller configured to suspend operation of the DLL when the clock signal operates at a first frequency, to set the DLL to operate based on a second frequency when the DLL is suspended, and to resume operation of the DLL when the clock signal operates at the second frequency without the need to relock the DLL.