POWER SUPPLY APPARATUS WITH IMPROVED TRANSIENT CHARACTERISTIC TO ABRUPT VARIATION AND REDUCED POWER CONSUMPTION

摘要

PURPOSE: A power supply apparatus is provided to improve a transient characteristic of an abrupt variation of an output current and to reduce a power consumed when the output current increases by generating the output current within a predetermined permissible variation rage from an input current. CONSTITUTION: A power supply apparatus includes an output current detector, a comparator(4), an output controller(2b), an offsetter(3), and an output voltage comparator(2). The output current detector generates a monitoring voltage commensurate with an output current. The comparator changes an output level according to whether the monitoring voltage is higher than a predetermined threshold level. The output controller controls an output voltage based on an output signal from the comparator. The offsetter provides the monitoring voltage with an offset. The output voltage comparator controls a magnitude of the offset according to a comparison result between the output voltage and a predetermined reference voltage. When generating the output voltage within a predetermined permissible variation range from an input voltage, the output voltage comparator controls a magnitude of the offset so that the output voltage decreases within the permissible variation range as the output current increases.