| 摘要 |
PROBLEM TO BE SOLVED: To provide an LSI having a power-saving control function that attains quick restart of circuit operations after receiving a restoration request. SOLUTION: When a power supply control circuit 10A receives a restoration request signal WKUP, a power-down signal PD outputted from a control section 11A goes to an 'L' and application of a power supply voltage VDDV is started to a circuit block 20 via a transistor(TR) 12. The power supply voltage VDDV is also given to a comparator 15, where the power supply voltage DVVD is compared with a reference voltage VREF. When the power supply voltage VDDV reaches the reference voltage VREF, a comparison signal CMP of the comparator 15 goes to an 'H'. Thus, the control section 11A gives a start signal STA to a counter 13 to release a reset signal inverse of RST to the circuit block 20 after a prescribed time. Since the power supply voltage VDDV applied actually to the circuit block 20 is monitored in this way, it is not needed to take an excess margin so as to quickly restart the circuit operation.
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