Patent ID: 7446586

Claim:
A pulse generator controlled by a control signal, wherein a pulse signal to be used in a semiconductor device is generated by the pulse generator when a frequency of an external input signal applied to the semiconductor device is less than a predetermined frequency, the pulse generator comprising: a first driving unit having first and second inputs, an output, and being turned on and off by said external input signal, which is input to said first input of first driving unit; a latch having an input and an output, said latch input being coupled to the first driving unit output and which latches a first power supply voltage from the first driving unit; a delay circuit having an input coupled to the latch output and an output coupled directly to said second input of the first driving unit, said delay circuit receiving a positive-going signal at its input and delaying the output of said positive-going signal to said second input of said first driving unit by a predetermined time; and a second driving unit having an input directly coupled directly to the delay circuit output and having an output coupled to the input of the latch and being turned on and off by an output signal of the delay circuit; wherein the external input signal input to said first input of first driving unit is directly used as an internal clock signal of the semiconductor device when the frequency of the external input signal is over the predetermined level; and wherein the control signal varies logically in accordance with a frequency range of the external input signal.