| 摘要 |
PROBLEM TO BE SOLVED: To rapidly reactivate oscillation, by accurately detecting that the oscillation of an oscillation circuit built in an electronic device has stopped. SOLUTION: A first n-channel MOS transistor 13 is driven by an oscillation signal CK to charge a first capacitor 14. When the oscillation stops, the charges stored in the first capacitor 14 is applied to a first p-channel MOS transistor 15 as a discharged current to discharge the first capacitor 14; and it is detected whether the oscillation is performed, on the basis of the voltage of the first capacitor 14. A gate bias potential VREF to be applied to the gate terminal of the MOS transistor 15 is set at a potential to be outputted from the sixth n-channel MOS transistor 52 of a regulator 2, and fallen from a high-potential side power supply potential VDD by the potential difference between a low-potential side power supply potential VSS and the threshold of the n-channel MOS transistor. COPYRIGHT: (C)2005,JPO&NCIPI
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