| 摘要 |
A charge pump circuit including a step-up section (1) having an output point to which a load is connected, the step-up section (1 ) having a function to step up an output potential from a predetermined potential lower than a potential (VPP) of a power supply to a desired potential higher than the power supply potential (VPP), wherein the charge pump circuit comprises initial potential setting switch (N10) connected between the power supply and the output point of the step-up section (1), and operative so that it is turned on with the beginning of the step-up operation of the step-up section (1) to propagate the power supply potential (VPP) to the output point of the step-up section (1), and that it is turned off in a suitable time. With the beginning of the step-up operation of the step-up section (1), the initial potential setting switch (N10) is turned on. As a result, a power supply potential (VPP) is propagated to the output point of the step-up section (1). Thus, the output potential is initially set to a relatively high potential obtained by subtracting a voltage drop of the initial potential setting switch (N10) from the power supply potential (VPP). When the output of the step-up section (1) rises to some extent in a suitable time, the initial potential setting switch (N10) is turned off. After that, the step-up section (1) delivers a voltage to the load.
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