| 摘要 |
PROBLEM TO BE SOLVED: To provide an optical response semiconductor switch for which circuit operation stability of an over-current protection circuit is improved and breakdown strength against breakdown caused by heat of an output MOSFET is improved. SOLUTION: The optical response semiconductor switch is equipped with an optical electromotive force element 1, an output MOSFET 2 driven by the electromotive force, an over-current sensor circuit 4 composed of a current detection resistor 41 for detecting the drain current and a first MOSFET 42, a gate shutdown circuit 5 composed of a first current-limiting resistor 51, a diode 52, and a shunt MOSFET 53, an over-current protection circuit 3 configured with a latch circuit 6 composed of a second and a third current-limiting resistor 61 and 62 as well as a second and a third MOSFETs 63 and 64. The circuit impedance of the over-current protection circuit 3 is the output voltage of the optical electromotive force element 1 on state transition of the latch circuit 6 and a value specified by current flowing in the over- current protection circuit 3 at this time during the over-current protection operation, and the circuit impedance is the output voltage of the optical electromotive force element 1 and a value specified by current flowing in the over-current protection circuit 3 at this time besides the over-current protection operation. COPYRIGHT: (C)2003,JPO
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