Direct-current power supply and battery-powered electronic apparatus and equipped with the power supply

摘要

A bypass control section ( 6 ) maintains a bypass switch ( 5 ) in the ON state during the period when a battery voltage (Vi) is higher than the output voltage (Vo) to an external load (L). Upon falling of the output voltage (Vo) at a desired voltage (ET), a converter control section ( 4 ) starts switching control at once, and a step-up chopper ( 3 ) promptly starts boost operation. The bypass control section ( 6 ) maintains the bypass switch ( 5 ) in the ON state from the start of the boost operation of the step-up chopper ( 3 ) until the match between the battery voltage (Vi) and the output voltage (Vo).