| 摘要 |
PROBLEM TO BE SOLVED: To provide a capacitor adjusting circuit capable of adjusting the capacitance of a variable capacitor with high precision. SOLUTION: This capacitor adjusting circuit is provided with a switch 109 and a load 110. At the time of discharging, a switch 105 is opened, and switches 107 and 109 are closed. This discharges the parasitic capacitor between the gate and the drain of an nMOX transistor 103 simultaneously with discharging the variable capacitor 106. At the time of charging, the switch 105 is closed, and the switches 107 and 109 are opened. This charges the variable capacitor 106 and makes terminal voltage Vc rise. Since discharging of the parasitic capacitor can be performed at the time of discharging, stored electric charge of the parasitic capacitor is prevented from contributing to the terminal voltage Vc. Then, the influence of the parasitic capacitor is eliminated to improve the adjustment system of the capacitance. COPYRIGHT: (C)2004,JPO
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