| 摘要 |
<P>PROBLEM TO BE SOLVED: To provide an over-current protection circuit that detects a temperature of a semiconductor element with high sensitivity in spite of a small consumption current and protects the semiconductor element from being overheated by interrupting the semiconductor element when the temperature reaches a prescribed temperature. <P>SOLUTION: The over-current protection circuit includes: a bipolar transistor 2; a bipolar transistor leakage current detection resistor 3; and an interruption circuit 4, which exist between a gate electrode and a source electrode of an output MOSFET 1. Since the output MOSFET 1 generates heat at flowing of an over-current therethrough and a leakage current of the bipolar transistor 2 thermally coupled to the output MOSFET 1 is increased, a voltage across the bipolar transistor leakage current detection resistor 3 is increased. The interruption circuit 4 is activated on the basis of thereof to protect the output MOSFET 1 from overheat due to the over-current. Since the bipolar transistor 2 amplifies a small leakage current into a high current, the bipolar transistor 2 can detect a temperature change with high sensitivity in spite of the small consumed current. <P>COPYRIGHT: (C)2007,JPO&INPIT |
