| 摘要 |
PURPOSE:To suppress a rush current which is applied when a first switching means is closed by a method wherein a comparing means which compares a voltage of a motor load side with a predetermined value, a control means which controls switching of a second switching means in accordance with a signal from the comparing means and a current limiting means which is provided in parallel with the second switching means are provided. CONSTITUTION:If a switch 1 is closed at a timing B after a certain lapse of time from a timing A at which the switch 1 is opened, a charging current is applied to a capacitor 4 through a resistor 6 and the potential of the capacitor 4 rises gradually. When the voltage V2 of the capacitor 4 exceeds the Zener voltage of a Zener diode 8, the base current of a transistor 7 is supplied and the transistor 7 is turned on and a transistor 5 is also turned on at a timing C. In this state, the capacitor-4 is quickly charged through the transistor 5. Although a rush current is applied to the capacitor 4 at that time, as the capacitor 4 is already charged to have a relatively high voltage at the timing C, the rush current can be suppressed substantially. |
