POWER SUPPLY APPARATUS CONTROLLING OUTPUT VOLTAGE OF BOOST CONVERTER ACCORDING TO THE INPUT VOLTAGE

摘要

PURPOSE: A highly-efficient power supply apparatus is provided to reduce power loss of switching element by adjusting output voltage of a booster converter in accordance with an input voltage. CONSTITUTION: A power supply apparatus comprises a comparing unit(202) for comparing sensed AC input voltage and reference voltage, and outputting first to third signals of comparison result; an output voltage adjusting unit(203) for outputting first to third output voltage level adjustment signals for varying output voltage levels in accordance with the first to third signals of comparison result; a control unit(204) for outputting a switching signal with adjusted duty ratio in accordance with the first to third output voltage level adjustment signals; and an output unit(205) for rectifying and smoothing input voltages induced to a secondary coil of a transformer(T) in accordance with the switching signal, and outputting a predetermined voltage.