| 摘要 |
PURPOSE:To save a base power by connecting a plurality of power transistors controlled at the bases separately in parallel to form a chopper circuit, and supplying a base current only to the transistors of the number in response to the load current. CONSTITUTION:A plurality of power transistors 12a-12n are connected in parallel to form a transistor chopper circuit 12, and connected in series with a load 11 such as a DC motor. The transistors 12a-12n are separately supplied with base currents by a base controller 30 and controlled in conduction. A load current detector 20 is inserted into a load current circuit, the number of the transistors to be conducted by the value of the load current and a command signal from an instructing unit 33 are decided, and base currents are supplied only to the transistors 12a-12n of the number. |
