| 摘要 |
PROBLEM TO BE SOLVED: To provide a charge pump type booster circuit the performance of which is improved by adding a simple additional circuit. SOLUTION: A booster circuit 1 has an oscillator circuit 11 and a charge pump circuit 13 comprising a rectifier element composed of an NMOS transistor driven by the output of the oscillator circuit to output a higher potential than a power source potential and a capacitor and comprises a comparator circuit 4 for comparing the output potential of the charge pump circuit 13 with a set value to generate a control signal and a substrate bias circuit 5 for variably controlling a substrate bias voltage of the NMOS transistor according to the control signal outputted from the comparator circuit 4. The comparator circuit 4 detects that the output potential of the charge pump circuit 13 exceeds the set value to output a control signal, and the bias circuit 5 is activated by the control signal to rectify the output of the oscillator circuit 11, thereby transferring it as a positive substrate bias voltage.
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