| 摘要 |
PURPOSE:To reduce the profile even of a motor having supply voltage specifications by providing a drive transistor, a current detecting means, a comparator, an OFF time setting means, and a flip-flop circuit to be reset by the output therefrom. CONSTITUTION:Description is made for a case in which motor driving current increases due to increase of load to cause increase of detection voltage of a current detecting resistor 16 upto the voltage V21 of a constant voltage supply 21 setting a current limit threshold. In this case, output of a comparator 20 is inverted and a transistor 22 is turned OFF whereas a transistor 24 is turned ON and thereby the set terminal S of a flip-flop circuit 30 goes Low. Consequently, a transistor 33 is turned OFF to pull the reset terminal R High thus turning a transistor 32 ON. As a result, a transistor 35 is turned OFF whereas transistors 38, 40 are turned ON. When a transistor 40 is turned ON, collector signal thereof causes turn OFF of driving transistors 13-15. |
