| 摘要 |
<P>PROBLEM TO BE SOLVED: To provide a switching power supply device that can reduce unnecessary power losses while maintaining high efficiency under a light load condition during a main function operating mode. <P>SOLUTION: The switching power supply device comprises: a first switch outputting a power supply voltage as a main voltage; a second switch outputting a power supply voltage as a first standby voltage; a main power supply circuit outputting the main voltage from the first switch; a standby power supply circuit outputting the first standby voltage from the second switch; a main voltage output unit outputting the main voltage from the main power supply circuit and determining a load condition of the main power supply circuit; a power supply control circuit outputting the main voltage from the main power supply circuit as a second standby voltage by a request from a main voltage output unit; a standby voltage output unit outputting the first or second standby voltage. When a load of the main power supply circuit is light, the main voltage output unit outputs the second standby voltage to the power supply control circuit and opens the second switch. <P>COPYRIGHT: (C)2012,JPO&INPIT |
