| 摘要 |
<P>PROBLEM TO BE SOLVED: To provide a protective circuit which does not require a current detecting resistor, interrupts a current when a driving circuit of a motor control circuit as a load has an abnormality such as short circuit, and applies a current again when the driving circuit returns to a normal state. <P>SOLUTION: In the protective circuit, an input voltage (a) is applied to a load side via a transistor Tr1, a comparing means (c) compares a voltage of the transistor Tr1 on the load side with a reference voltage (b), and, when the voltage of the load side of the transistor Tr1 becomes lower than the reference voltage (b), the transistor Tr1 is controlled to be turned off on the basis of the output of the comparing means (c). In this protective circuit, a base current of the transistor Tr1 is set so that if an overcurrent higher than a predetermined current value is applied to the load, a voltage between an emitter and a collector of the transistor Tr1 may become larger than a predetermined voltage value, and the voltage of the load side of the transistor Tr1 may become lower than the reference voltage (b). Further, a restoring resistor RX is connected in parallel to the transistor Tr1. <P>COPYRIGHT: (C)2008,JPO&INPIT |
