| 摘要 |
Improvement technology of a charge pump circuit is provided for avoiding device destruction due to electrification of an intermediate node of plural capacitors coupled in series to form one step-up capacitor, and avoiding reduction of pump efficiency due to leakage current which flows through a leakage path of the intermediate node concerned. A charge pump circuit includes a step-up capacitor configured by a first capacitance and a second capacitance coupled in series, a capacitance driver, and a protection circuit. The protection circuit is set at a conductive state and discharges a stored charge at the series coupling node of the first capacitance and the second capacitance, when the step-up voltage is not generated, and the protection circuit is maintained in a non-conductive state, when the step-up voltage is generated. Accordingly, relaxation of the withstand voltage of the step-up capacitor is achieved, and reduction of the pump efficiency is avoided.
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