| 摘要 |
PURPOSE:To start load, in which impedance is changed, quickly by providing a second current supply means further supplying a semiconductor switch with currents when the applied voltage of the semiconductor switch is higher than reference voltage when the semiconductor switch is operated by a first current supply means and load is started. CONSTITUTION:When a motor 1 is started, an input signal S is input to an input terminal 6, a transistor 8 is turned on, currents I1 are made to flow through a collector from a constant current source 12 and a transistor 3 is turned on. Since impedance at the time of the starting the motor 1 is reduced, large collector currents IC flow through the transistor 3, voltage VCE between a collector and an emitter is increased, a comparator 14 outputs an H level signal to an AND circuit 15 and a transistor control section 16 turns a transistor 17 on. Accordingly, base currents IB of the transistor 3 are increased, voltage VCE between the collector and the emitter is inhibited at a low value, and supply voltage from a power supply 4 to the motor 1 is augmented, thus quickly starting the motor 1. |
