POWER SUPPLY CIRCUIT

To provide a power supply circuit in which prolongation of a lifetime of a life-limited capacitor is attained.SOLUTION: A power supply circuit comprises: a changeover circuit configured by connecting in parallel a plurality of series circuits each constituted of a life-limited capacitor and a switch; and a control circuit which executes changeover control for performing ON/OFF changeover of the plurality of switches and bringing any one of the plurality of life-limited capacitors into an electrified state. The control circuit monitors a physical quantity which becomes an index indicating a lifetime of each life-limited capacitor, determines whether or not each of the life-limited capacitors reaches the end of its lifetime on the basis of a monitored result and, based on a determined result, executes the changeover control in such a manner that the other life-limited capacitor which does not reach the end of its lifetime is brought into the electrified state before a life-limited capacitor in the electrified state reaches the end of its lifetime.SELECTED DRAWING: Figure 1 【課題】有寿命コンデンサの長寿命化を図った電源回路を得る。【解決手段】有寿命コンデンサとスイッチとで構成される直列回路を、複数個、並列接続して構成された切り替え回路と、複数のスイッチのオンオフ切り替えを行い、複数の有寿命コンデンサのいずれか１つを通電状態とする切り替え制御を実行する制御回路とを備え、制御回路は、各有寿命コンデンサの寿命を示す指標となる物理量を監視し、監視結果に基づいて、各有寿命コンデンサが寿命に到達しているか否かを判断し、判断結果に基づいて、通電状態である有寿命コンデンサが寿命に到達する前に、寿命に到達していない他の有寿命コンデンサを通電状態とするように切り替え制御を実行する。【選択図】図１