SEMICONDUCTOR DEVICE INCORPORATING CLOCK GENERATING CIRCUIT

摘要

PURPOSE: A semiconductor device incorporating clock generating circuit is provided, which is capable of performing a prescribed operation with appropriate timing synchronizing with an external clock even if the frequency of the external clock is varied. CONSTITUTION: The semiconductor device is operated responding to a control clock(ISGs) generated by a control clock generating circuit(10). The control clock generating circuit(10) comprises a DLL circuit(20) detecting an external clock cycle(Tc) by synchronous operation, a reference clock pulse generating circuit(60) activated synchronizing with the external clock(CLK) and generates a reference clock pulse(CLKP) having pulse width responding to the external clock cycle(Tc). The control clock generating circuit(10) further includes a delay circuit(90) outputting a delay clock pulse(CLKD) by delaying the reference clock pulse(CLKP) by each unit delay time responding to the external clock cycle(Tc), and an internal control clock generating circuit(95) setting activation timing and non-activation timing of the control clock(ISGs) based on the delay clock pulse(CLKD).