Delay control circuit, semiconductor memory device, and delay control method

Abstract

A delay control circuit provided herein includes a DLL control circuit, a delay line circuit, and an N-value detection circuit. The DLL control circuit determines the delay amount based on the phase difference between the input and output clock signals. The delay line circuit delays the input clock signal based on the delay amount to generate an output clock signal. The N-value detection circuit performs an N-value detection operation for detecting the number of delayed clock cycles from the input clock signal to the output clock signal. When it is determined to be in an overflow state, the DLL control circuit outputs a signal indicating an overflow state to the N-value detection circuit. When the signal indicating the overflow state is received, the N-value detection circuit does not perform the N-value detection operation, but instead sets the number of delayed clock cycles to a predetermined value.