ELECTRONIC CIRCUIT

摘要

When an overcurrent is detected by an overcurrent detecting circuit (36), a first switch circuit (32) selects a second input terminal (b) and connects an output terminal (c) to the second input terminal (b), with the result that the output terminal (c) of the first switch circuit (32) is put into a high-impedance state. The second switch circuit (34) selects a second output terminal (f) and connects an input terminal (d) to the second output terminal (f), with the result that the input terminal (d) of the second switch circuit (34) is grounded. That is, the gate of a first MOSFET (21) is grounded via a current interrupting resistor (35). The resistance value of the current interrupting resistor (35) is set so that, at the time of a current interruption, a time interval from a time when the gate-source voltage or gate-emitter voltage of the switching device lowers to such a voltage that the temperature characteristics of the on-resistance of the switching device become negative to a time when the drain current or collector current of the switching device reaches 2% of the saturation current thereof is 500 [nsec] or less.

主权项

1. An electronic circuit comprising:
a switching device including a plurality of switching elements that are connected in parallel and chiefly made of SiC; an overcurrent detecting circuit to detect that an overcurrent is flowing in the switching device; and an overcurrent protecting circuit to interrupt a current flowing in the switching device when an overcurrent is detected by the overcurrent detecting circuit, wherein the overcurrent protecting circuit is arranged such that, at the time of a current interruption, a time interval from a time when the gate-source voltage or gate-emitter voltage of the switching device lowers to such a voltage that the temperature characteristics of the on-resistance of the switching device become negative to a time when the drain current or collector current of the switching device reaches 2% of the saturation current thereof is 500 [nsec] or less.