| 摘要 |
<p><P>PROBLEM TO BE SOLVED: To provide a charging circuit that quickly charges a capacitor by a step-up voltage, while suppressing power consumption and noise. <P>SOLUTION: The charging circuit includes a charge pump circuit that generates a step-up voltage generated, by stepping up the input voltage for each time interval which becomes short, according to then increase in the frequency of a clock signal to be inputted, an integrating circuit for integrating the step-up voltage so as to apply it to a capacitor, and a clock signal output circuit. The clock signal output circuit is configured, such that the clock signal output circuit outputs a second clock signal, having a higher frequency than that of a first clock signal to the charge pump circuit as a clock signal, and then, the clock signal output circuit outputs the first clock signal to the charge pump circuit as a clock signal so that a charging voltage becomes a prescribed level, in an interval which is shorter than the interval required for a charging voltage of the capacitor to reach the prescribed level, when the first clock signal is inputted to the charge pump circuit as a clock signal. <P>COPYRIGHT: (C)2011,JPO&INPIT</p> |
