| 摘要 |
PROBLEM TO BE SOLVED: To make rapid activation and reduction of electric current consumption compatible with each other by using a clock signal of a predetermined frequency in a semiconductor integrated circuit including a booster circuit generating a desired step-up voltage by boosting a supplied power source voltage. SOLUTION: The semiconductor integrated circuit includes the booster circuit which performs charge pump operation in compliance with a clock signal, an oscillation circuit which generates an oscillation signal having the prescribed frequency, a frequency dividing circuit which generates the clock signal by dividing the frequency of the oscillation signal by a set frequency dividing ratio, a counter which obtains a count value by counting the pulses included in a frame synchronizing signal or the oscillation signal or the clock signal, and a clock frequency control circuit which sets the first frequency dividing ratio in the frequency dividing circuit at the time of startup and controls the frequency of the clock signal supplied to the booster circuit by setting the second frequency dividing ratio when the count value attains the prescribed value. COPYRIGHT: (C)2007,JPO&INPIT
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