| 摘要 |
PURPOSE:To make the capacity of a Zener diode connected to each path smaller and to reduce the cost by providing a plurality of paths for releasing energy caused by counter-electromotive force. CONSTITUTION:A snubber circuit for releasing a surge voltage generated by a counter-electromotive force in coils L1 and L2, when transistors Q1 and Q2 are turned off, is provided in a motor drive circuit. The snubber circuit has a path for releasing a current created by the counter-electromotive force in the coil L1 at the time of a transistor Q1 turned off, through a path of circuit comprising a diode D1 a Zener diode ZD1 resistor R1 indicated by an arrow 'a' and another path of circuit comprising a diode D2 Zener diode ZD2 resistor R2 indicated by an arrow 'b', by which a surge voltage generated at the time of the transistor Q1 turned off is absorbed. Therefore, the capacity of the Zener diodes ZD1 and ZD2 connected to respective paths can be one- half of the capacity compared with the case where only one path is available, so that low-cost Zener diodes can be utilized. |
