| 摘要 |
PROBLEM TO BE SOLVED: To provide a power supply circuit to supply the voltage of different systems, which surely supplies power to a circuit requiring a higher voltage after supplying a power to the circuit requiring a lower power supply voltage. SOLUTION: A switch element 32 is opened before the potential of an output terminal Vo reaches VCC, more specifically when reaching VCC-VCEQ3 , by monitoring change of the potential of the output terminal Vo of a 5 V system power supply part 20 using a switch control circuit 31 in a 3.3 V system power supply part 30, so that a regulator 33 in the 3.3 V system power supply part 30 is turned on. Then, after the power is supplied to the 3.3 V system circuit from the regulator 33, along with a lapse of a specified delay, the voltage VCC is supplied to the 5 V system circuit. |
