| 摘要 |
PROBLEM TO BE SOLVED: To provide a power supply circuit of high efficiency by using a charge pump circuit for preventing a loss in forward direction voltage of a reverse current preventive diode, and generation of a reactive current of a parasitic diode of a MOS transistor and generation of a latch-up even in an IC structure, while a constant output voltage is obtained even from a battery as a DC power supply which decreases the voltage gradually as it is used. SOLUTION: The power supply circuit includes a charge pump circuit 3 with three mode voltage boosting operations, such as a first operation mode of 1-fold boosting, a second operation mode of 1.5-fold boosting, a third operation mode of 2-fold boosting. The charge pump circuit 3 is operated in first, second or third operation mode according to the power-supply voltage VDD. COPYRIGHT: (C)2004,JPO
|
