| 摘要 |
An object is to provide a power supply circuit, display device and electronic instrument which can reduce the power consumption in the power supply circuit itself and which can set a boosting ratio according to the duty ratio. The power supply circuit comprises: a charge pump circuit including a first switching unit (40) for charging a capacitor CP and a second switching unit (42) for transferring the charge in the capacitor CP to another capacitor CB; and a circuit for generating switching signals for controlling the first and second switching units. The first switching unit (40) includes switching elements SW11A and SW11B each of which is connected at one end to a different potential VDD or VE1, the other end thereof being connected to one end of the capacitor CP. The switching signal generation circuit controls ON and OFF-states of the switching element SW11A while turning the other switching element SW11B off, or controls ON and OFF-states of the switching element SW11B while turning the other switching element SW11A off. Thus, the boosting ratio can variably be controlled. The potential of the switching signal in the OFF state is equalized with a potential supplied to the source of a switching transistor. At a partial display on a liquid crystal display device, the boosting ratio is controlled according to the duty ratio.
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