DEVICE FOR CHARGING SECONDARY BATTERY

摘要

PROBLEM TO BE SOLVED: To provide a device for charging a secondary battery which saves power in a light load condition by dispensing with a bleeder resistor.SOLUTION: A power circuit is connected to a primary winding 1a of a transformer T, and a switching element 4 is connected to the power circuit. A main winding 1b and a sub winding 1c are connected on a secondary side of the transformer T. A charging circuit 10 for supplying power to a battery pack 30 to be charged is connected to the main winding 1b, and a control circuit 20 for controlling on/off the charging circuit 10 or the switching element 4 is connected to the sub winding 1c. An LED 40 for indicating a standby state or charge completion is connected to the charging circuit 10. The LED 40 turns on in a light load condition of the charging circuit 10 under the command of the control circuit 20. The LED 40 is connected to the charging circuit 10 via a constant voltage circuit 41 connected in series. When the LED is flashed, an adjusting loading resistor R is controlled by a load adjustment circuit 43 to consume power of the charging circuit while the LED 40 is off.