| 摘要 |
PROBLEM TO BE SOLVED: To solve such a problem that abnormal conditions are likely to occur in display, when the step-up magnification of a power supply voltage is changed. SOLUTION: A charge pump circuit includes a first charge pump circuit 4 and a second charge pump circuit 5 that alternately execute a step-up operation in a prescribed period, and a control circuit 6 that controls each step-up operation of the first and second charge pump circuits. A first inverter in the nth stage is provided in the control circuit 6. A positive power supply voltage is supplied to the first inverter from a second connection node between a corresponding second switch transistor in the nth stage and a second switch transistor in the n-1th stage. A negative power supply voltage is supplied to the first inverter from a first connection node between a corresponding first switch transistor in the nth stage and a first transistor in the n+1th stage. The first inverter is inputted with an output from the first connection node between the corresponding first switch transistor in the nth stage and a first transistor in the n-1th stage. The first inverter outputs an output voltage to a gate of the corresponding first switch transistor in the nth stage. COPYRIGHT: (C)2011,JPO&INPIT
|
