| 摘要 |
PURPOSE:To supply a small DC power over a long time and a large DC current in a short time by a battery, when an external AC power supply is cut off. CONSTITUTION:An AC/DC converter 1 for outputting a DC power by using an external AC power supply as its input, a first DC/DC converter 2 using the output of the AC/DC converter 1 as its input, a second DC/DC converter 3 whose operation is started or stopped by an external ON or OFF signal, a battery 6 connected with these converters 2, 3 on their input sides respectively, a charging circuit 4 for charging the battery 6, and a relay 5 whose driving part is connected with the output side of the second DC/DC converter 3 are provided respectively. When the external AC power supply is cut off from the AC/DC converter 1, both the foregoing DC/DC converters 2, 3 are operated by the battery 6 in a short time. Thereafter, by an OFF signal given from the external, the operation of the second DC/DC converter 3 is stopped, and a normally open contact 5A is made open. Thereby, the DC output fed from the second DC/DC converter 3 is cut off, and only the first DC/DC converter 2 is operated. |
