| 摘要 |
<P>PROBLEM TO BE SOLVED: To control an output voltage of a charge pump circuit stably by feedback control of a PWM system. <P>SOLUTION: The charge pump circuit comprises first and second charge transferring MOS transistors M1, M2 connected in series; a capacitor C1 connected at its first terminal to the connection point of the MOS transistors M1, M2; an integrating circuit 21 that generates a ramp voltage corresponding to a clock CLK; a comparator 15 that compares the ramp voltage with a voltage corresponding to an output voltage Vout from the second MOS transistor M2; a frequency divider 22 that divides the clock CLK into a half; and a NAND circuit 16 that masks an output of the comparator 15 according to a frequency-divided output of the frequency divider 22. The output of the NAND circuit 16 is impressed to the second terminal of the capacitor C1. <P>COPYRIGHT: (C)2006,JPO&NCIPI |
