| 摘要 |
PURPOSE:To reduce in size a circuit and to decrease its cost by supplying a signal to the gates of a plurality of power control functional elements when the excess of a motor current is detected, thereby controlling currents flowing to the elements. CONSTITUTION:A command signal is input to a control logic circuit 6 to, for example, turn ON switches 14, 15 thereby to turn ON, power control Trs 10, 11 to supply a current IM to a motor 2. Further, switches 13, 16 are closed to turn ON Trs 9, 12 to supply a reverse current IM to the motor thereby to reversely rotate the motor 2. The current IM is supplied to the resistor 22 of current detecting means 5, a voltage drop VR is compared with a reference voltage Vref by a comparator 21. In case of VR>Vref, it is judged as being an overcurrent to turn ON a Tr 23. Then, diodes 18, 19 or 17, 20 are turned ON to turn OFF Trs 10, 11 or 9, 12, thereby stopping the motor 2. Thus, the power consumption of the circuit is deleted to reduce it in size and to decrease its cost. |
