AUTO PRECHARGE CONTROL CIRCUIT OF SEMICONDUCTOR MEMORY DEVICE FOR GENERATING STABLE AUTO PRECHARGE SIGNAL REGARDLESS OF FREQUENCY VARIATION OF EXTERNAL CLOCK SIGNAL

摘要

An auto precharge control circuit of a semiconductor memory device generating a stable auto precharge signal regardless of the frequency variation of an external clock signal is provided to stably assure a write recovery time and to prevent a write operation fail, by generating the auto precharge signal in order to compensate the write recovery time according to the frequency variation of the external clock signal. In an auto precharge control circuit(100) of a semiconductor memory device generating an auto precharge signal in response to a write command including an auto precharge command, an auto precharge sensing part(110) outputs an auto precharge sensing signal in response to a power-up detection signal, an auto precharge signal, a first control signal and a second control signal. A precharge control part(120) generates a precharge control signal in response to the auto precharge sensing signal and a write completion signal. A frequency detector(130) detects the frequency of an external clock signal in response to the power-up detection signal and a first write control signal, and generates a frequency detection signal according to the detection result. A precharge signal generator(140) generates the auto precharge signal in response to the power-up detection signal, the precharge control signal and the frequency detection signal.