| 摘要 |
<p><P>PROBLEM TO BE SOLVED: To provide a power supply circuit which ensures a sufficient backup time even if power consumption by a circuit unit requiring backup is large. <P>SOLUTION: The power supply circuit includes a first cutoff unit 11 which is set on a battery power supply line 21 to control supply and cutoff of battery power to a rear stage, a second cutoff unit 12 which controls supply and cutoff of battery power supplied from the first cutoff unit 11, to the rear stage, a first power supply unit 13 which generates first power (voltage: V1) based on battery power supplied from the first cutoff unit 11, and a second power supply unit 14 which generates second power (voltage: V2) based on battery power supplied from the second cutoff unit 12. The second cutoff unit 12 stops supplying battery power to the rear stage when the voltage of battery power supplied from the first cutoff unit 11 drops to a voltage equal to or lower than reference voltage Vr1. The first cutoff unit 11 stops supplying battery power to the rear stage when the voltage of battery power supplied from a battery 2 drops to a voltage equal to or lower than a reference voltage Vr2 lower than the reference voltage Vr1. <P>COPYRIGHT: (C)2009,JPO&INPIT</p> |
