Patent ID: 9007738
Filing Date: 2015-04-14
Classification: H02M,H03K

Abstract:
1. A transistor protection circuit for protecting a voltage-driven transistor that is switch-controlled by the application of a high-potential-side voltage or low-potential-side voltage of a power supply to a gate terminal of the transistor by a drive circuit, the transistor protection circuit comprising: a power supply controller that gradually lowers the high-potential-side voltage of the power supply upon receiving a protection command for executing protection of the transistor; a gate short-circuit part for causing short circuit in the gate terminal and a source or emitter terminal of the transistor; and a short-circuit controller for controlling the gate short-circuit part so as to cause short circuit in the gate terminal and the source or emitter terminal of the transistor in response to the protection command, wherein the short-circuit controller controls the gate short-circuit part so as to cause short circuit in the gate terminal and the source or emitter terminal of the transistor after a predetermined delay time period elapses since the reception of the protection command, and wherein the predetermined delay time period is equal to or longer than a time period required for the voltage, which is applied to the gate terminal of the transistor, to decline to a threshold voltage of the transistor.