Patent ID: 7245469
Filing Date: 2007-07-17
Classification: H02J

Abstract:
1. A DC backup power supply device comprising: an AC/DC converter for converting an AC power to a DC power; a DC/DC converter for receiving the DC output power of the AC/DC converter and controlling a voltage of the received DC output power; a bi-directional DC/DC converter connected to a DC path of a main circuit between said AC/DC converter and said DC/DC converter via first switching means, said main circuit having a load connected to the DC/DC converter; and DC power storage means connected to the bi-directional DC/DC converter, said device further comprising: wherein a smoothing capacitor is connected to a side of said bi-directional DC/DC converter having the first switching means, and said monitoring means includes means for charging said smoothing capacitor from said DC power storage means through the operation of said bi-directional DC/DC converter, means for turning ON said first switching means after the charging operation, and means for confirming a change in a voltage across said smoothing capacitor before and after the first switching means is turned ON.