| 摘要 |
PROBLEM TO BE SOLVED: To obtain a power supply circuit in which power consumption can be reduced under a sleep state and power can be supplied to a destination device even when it is operated intermittently under the sleep state. SOLUTION: When a CPU 11 operates normally, a power supply voltage VDD is lowered down to a voltage Va efficiently by operating a DC-DC converter 2 and then further lowered by a voltage regulator 3 down to a settled voltage Vb being supplied to the CPU 11. When the CPU 11 enters a sleep state, the DC-DC converter 2 enters an inactivated state and stops operation thus suppressing power consumption. The power supply voltage VDD passed through the DC-DC converter 2 is regulated to a desired voltage Vb only through the voltage regulator 3 and supplied to the CPU 11. |
