| 摘要 |
A boosting circuit is provided to improve current driving capacity, suppress an inrush current in case of charging, and reduce cost by removing resistors for detecting the change of an output voltage. A boosting circuit(1) includes a differential amplifier(OP1), a boosting capacitor(C1), a first switch device(Q1), a second switch device(Q2), a third transistor(Q3), a fourth switch device(Q4), and a first selecting unit(SEL1). The differential amplifier inputs a first electric potential, and outputs the electric potential according to the change of a second electric potential. The boosting capacitor repeats a charging period and a discharging period alternately. The first switch device is connected between a first reference electric potential higher than the first electric potential and one end of the boosting capacitor, and is turned on during the charging of the boosting capacity. The second switch device is connected between a second reference electric potential lower than the first electric potential and the other end of the boosting capacitor, and is turned on during the charging of the boosting capacitor. The third transistor as a third switch device is connected between the first reference electric potential and the other end of the boosting capacitor, and is turned on during the discharging of the boosting capacitor. The fourth switch device is connected between an output terminal of the second electric potential and one end of the boosting capacitor, and is turned on during the discharging of the boosting capacitor. The first selecting unit selects the second electric potential during the charging of the boosting capacitor, and the output electric potential of the differential amplifier during the discharging of the boosting capacitor, and provides the selected electric potential to the control terminal of the third transistor.
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