Semiconductor protection device and electric power conversion device

A semiconductor protection device which outputs a short-circuit detection signal to a gate drive circuit in a case where a semiconductor switching element is determined to be in a short-circuit state, the semiconductor protection device comprising:

• a first determination circuitry which outputs a first output signal when a gate drive signal for the semiconductor switching element has exceeded a predetermined first threshold;
• a second determination circuitry which outputs a second output signal when gate voltage of the semiconductor switching element has exceeded a second threshold;
• and
• a third determination circuitry which outputs a third output signal when a value based on voltage of the semiconductor switching element or a value based on a value of current flowing through the semiconductor switching element during a period in which the semiconductor switching element is turned ON has exceeded a third threshold, wherein
• determination operation of the third determination circuitry is activated by the third threshold being reduced by the first output signal, and a short-circuit state of the semiconductor switching element is detected on the basis of a logical conjunction of the second output signal and the third output signal.

A semiconductor protection device which outputs a short-circuit detection signal to a gate drive circuit in a case where a semiconductor switching element is determined to be in a short-circuit state, the semiconductor protection device comprising:

• a first determination circuitry which outputs a first output signal when gate voltage of the semiconductor switching element has exceeded a predetermined first threshold;
• a second determination circuitry which outputs a second output signal when the gate voltage has exceeded a second threshold greater than the first threshold;
• and
• a third determination circuitry having a first input connected to a circuit that changes from high voltage to voltage of a third threshold in accordance with the first output signal, and a second input connected to a high-potential terminal of the semiconductor switching element via a Desat capacitor, the second input being set to be higher than the voltage of the third threshold, the third determination circuitry being configured to output a third output signal when a value of the first input has become a value of the second input, wherein
• determination operation of the third determination circuitry is activated by the third threshold being reduced by the first output signal, and a short-circuit state of the semiconductor switching element is detected on the basis of a logical conjunction of the second output signal and the third output signal.