| 摘要 |
PROBLEM TO BE SOLVED: To provide a boosting circuit, which can discharge the charge accumulated in a capacitor used for charge pump operation with high speed in a simple structure, a power circuit, and a liquid crystal drive device. SOLUTION: A charge pump circuit 200 includes MOS transistors NSW1-NSW5 which are connected in series, with one end of a MOS transistor NSW1 supplied with system grounding power voltage GND, and a transistor DSW1 for discharge whose one end is supplied with system grounding power voltage GND and whose other end is connected to a node where the MOS transistors NSW4 and NSW5 are connected. The MOS transistors NSW1-NSW5 are materialized by triple well structure made on a p-type semiconductor substrate. In usual operation, the MOS transistor NSW5 is set to ON and the transistor DSW1 for discharge to OFF. In discharge operation, the MOS transistor NSW5 is set to OFF and the transistor DSW1 for discharge to ON, and a current path is made by a parasitic bipolar transistor element. COPYRIGHT: (C)2005,JPO&NCIPI
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