| 摘要 |
PURPOSE:To reduce the collector loss of a drive transistor by suitably controlling transistor group for opening and closing a current passage to a drive coil from one terminal of a DC power source and transistor group for opening and closing a current passage to the other terminal of the power source from the coil. CONSTITUTION:A current passage between one terminal of a DC power source 19 and drive coils 4a-4c is controlled to be opened or closed by the first drive transitors 1a-1c through the resistor 20 of a current detector 11. A current passage between the coils 4a-4c and the other terminal of the power source 10 is controlled to be opened or closed by the second drive transistors 2a-2c. Smoothing uits 3a-3c are respectively connected between the connecting points of the output terminals of the transistors 1a-1c and the terminals of the coils 4a-4c, and the output terminals of the transistors 2a-2c. The transistors 1a- 1c and 2a-2c are selectively driven by selectors 12, 13 on the basis of a switching signal of a switching signal generator 14. |
