| 摘要 |
A charge-pump circuit has means biasing electrical potential of a substrate of a MOS transistor for control M2 so that forward direction current does not flow substantially through a,parasitic diode Dp1. In the concrete, the substrate of the substrate of a MOS transistor for control M2 is biased by voltage of a connecting point of the substrate of a MOS transistor for control M2 and a capacitor 1 at the case that the substrate of a MOS transistor for control M2 is P-channel type. Thus, it is prevented that a parasitic diode is biased to forward direction in a charge-pump circuit carrying out voltage fluctuation with lower voltage step than power source voltage Vdd so as to carry out normally charge-pump operation.
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