| 摘要 |
<P>PROBLEM TO BE SOLVED: To provide a protective circuit that prevents a field-effect transistor provided between a DC power source and a load from being interrupted unnecessarily and that can reliably protect the field-effect transistor and power lines. <P>SOLUTION: A MOSFET Q1 is provided between a battery B and the load 10. A series circuit constituted of a Zener diode ZD1 and a transistor Q31 is provided between the gate and the source of the MOSFET Q1. If an overcurrent causes a voltage Vds between the drain and the source of the MOSFET Q1 to exceed a reference voltage Vref1, a comparator CP1 turns on the transistor Q31 to clamp the voltage between the drain and the source of the MOSFET Q1 to the Zener voltage Vzd1 of the Zener Diode ZD1 so that the overcurrent is suppressed. <P>COPYRIGHT: (C)2006,JPO&NCIPI |
