Patent ID: 7562237

Claim:
A semiconductor integrated circuit device, comprising: a semiconductor substrate; an oscillator formed on said semiconductor substrate, and for outputting a monitoring clock signal, said monitoring clock signal having a frequency that depends on a manufacturing process; an internal circuit formed on said semiconductor substrate; a frequency comparison circuit for comparing the monitoring clock signal outputted by said oscillator with a reference clock signal having a certain frequency, and for outputting a differential signal corresponding to the difference between the frequencies of the monitoring clock signal and the reference clock signal, wherein the frequency comparison circuit includes: a pulse thinning circuit for outputting a thinned-out clock signal by thinning out (n−2) pulses for every n pulses included in the reference clock signal, and for maintaining two pulses; a frequency dividing circuit for frequency-dividing the monitoring clock signal to a 1/n frequency thereof, and for outputting a frequency-divided clock signal; a differentiating circuit for differentiating the frequency-divided clock signal outputted by said frequency dividing circuit in synchronization with the reference clock signal, and for outputting a differentiated clock signal; a pulse number comparison circuit for comparing the number of pulses of the thinned-out clock signal outputted by said pulse thinning circuit with the number of pulses of the differentiated clock signal outputted by said differentiating circuit, and for generating the differential signal in accordance with the obtained difference; and an internal power supply circuit for supplying an internal power voltage to said internal circuit, corresponding to the differential signal outputted by said frequency comparison circuit.