摘要 |
A microcomputer includes a first switch coupled between a main power supply terminal and a power supply node, and a second switch coupled between an auxiliary power supply terminal and the power supply node. The microcomputer compares a voltage V1 of the main power supply terminal with a reference voltage VR1. When V1>VR1, the microcomputer turns on the first switch and turns off the second switch, and when V1<VR1, the microcomputer turns off the first switch, and turns on/off the second switch to gradually increase a voltage V3 of the power supply node. Thus, the operation of a clock generation circuit driven by V3 can be stable even when V3 is changed from V1 to V2. |