| 摘要 |
PURPOSE:To effectively prevent an arm from shortcircuiting when an AC motor is controlled to be braked by transmitting a brake signal through a delay circuit to a main transistor base driver of one side arm. CONSTITUTION:When an AC motor M is braked to be stopped, if a control signal is turned OFF, a brake signal is transmitted from a brake signal generator 15, and a circuit bias 16 is turned OFF by the rise of the brake control signal. As a result, current sources 11, 11A are turned OFF, and main transistors 1, 2, are turned OFF. Since the brake signal is inverted by an inverter 17 and supplied to the base of a transistor 19, a transistor 20 is turned ON, current mirrors T3-T5 are sequentially driven to turn ON a transistor 7, a main transistor 1 is turned ON by time delay from the generating time of the brake signal, and an AC motor M is braked. |
