Delay device having a delay lock loop and method of calibration thereof

Abstract

A signal delay device having an internal delay lock loop for calibrating the delay interval. The signal delay device receives an input signal and then outputs the signal after a pre-defined delay period. The input signal varies according to a reference clock signal, and the required delay period is a quarter cycle of the clock signal. The delay device includes a multiplexer, an inverter, a phase detector, a counter and a delay element. During calibration, the phase detector, the counter and the delay element form a delay lock loop that can set up the delay time automatically.