| 摘要 |
PURPOSE:To provide a step motor driver in which generation of heat is normally suppressed and quick operation is conducted as required. CONSTITUTION:A quick discharge circuit comprising a first diode 61 for preventing counter flow of current, a switch element 62 connected in parallel therewith, a Zener diode 63 connected between the gate of the switch element 62 and the ground, and a transistor 64 for controlling the switching is inserted between a power supply bus 60 and the high voltage arm of an H bridge. A control section controls the base of the transistor 64 to allow or forbid quick discharge. When the operating speed of step motor is low, quick discharge is forbidden and a surge higher than a predetermined voltage is collected to the power supply bus 60. When the operating speed is high, quick discharge is allowed and the surge is absorbed by the Zener diode 62. |
