| 摘要 |
PROBLEM TO BE SOLVED: To improve the current driving capacity to a boosting capacitor without increasing a footprint as a device, in a charge pump type voltage booster circuit. SOLUTION: In the charge period of a capacitor C1, a PMOS transistor Q1 and an NMOS transistor Q2 are turned on, and the capacitor C1 is charged with electricity by the voltage between potential VCC and potential VSS. On the other hand, in the discharge period of the boosting capacitor, the PMOS transistor Q3 and the PMOS transistor Q4 are turned on, and the charge accumulated in the boosting capacitor is discharged. In the discharge period of the capacitor C1, a selector SEL1 selects a terminal T1, and a feedback system is formed, where the operation voltage applied to the gate of the PMOS transistor Q3 changes according to the fluctuation of output voltage VDD2. At that time, only the resistance components of the PMOS transistor Q3 exists and a differential amplifier does not exist on the path (between the potential VCC and the low-voltage-side terminal C1N of the boosting capacitor) of the current flowing into the capacitor C1. COPYRIGHT: (C)2008,JPO&INPIT
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