Abstract: A gate drive circuit according to an embodiment includes: a voltage detector that detects a voltage between a first terminal and a second terminal of a switching device; a delay circuit that outputs, with a delay for a predetermined time, a detected value of the voltage obtained from the voltage detector; and a first off-mode drive circuit and a second off-mode drive circuit that apply a control signal to a control terminal of the switching device for turning off the switching device, wherein the first off-mode drive circuit turns off the switching device faster than the second off-mode drive circuit, and stops its operation to turns off the switching device when the delayed voltage value output from the delay circuit exceeds a predetermined threshold value.

Abstract: According to an embodiment, a semiconductor device includes a first metal plate, a second metal plate, and two or more semiconductor units. The two or more semiconductor units are disposed on the first metal plate. The each of the two or more semiconductor units includes a first metal member, a second metal member, and a semiconductor element. The first metal member has a first connection surface connected to the first major surface. The second metal member has a second connection surface connected to the second major surface. The semiconductor element includes an active region having surfaces respectively opposing the first connection surface and the second connection surface. A surface area of the first connection surface is greater than a surface area of the surface of the active region opposing the first connection surface. A surface area of the second connection surface is greater than a surface area of the surface of the active region opposing the second connection surface.

Abstract: According to an embodiment, a semiconductor device includes a first metal plate, a second metal plate, and two or more semiconductor units. The two or more semiconductor units are disposed on the first metal plate. The each of the two or more semiconductor units includes a first metal member, a second metal member, and a semiconductor element. The first metal member has a first connection surface connected to the first major surface. The second metal member has a second connection surface connected to the second major surface. The semiconductor element includes an active region having surfaces respectively opposing the first connection surface and the second connection surface. A surface area of the first connection surface is greater than a surface area of the surface of the active region opposing the first connection surface. A surface area of the second connection surface is greater than a surface area of the surface of the active region opposing the second connection surface.

Abstract: According to one embodiment, a semiconductor switch includes a main element including a switching element and an antiparallel diode, and a reverse voltage application circuit. The reverse voltage application circuit includes an auxiliary electric-power supply, a high-speed free wheeling diode, an auxiliary element, and a capacitor. The high-speed free wheeling diode comprises a plurality of diodes connected in series.

Abstract: According to one embodiment, a semiconductor switch includes a first element that includes a switching element and an anti-parallel diode. The switching element has a breakdown voltage and is coupled to a control terminal and second and third terminals. The semiconductor switch further includes a second element having a breakdown voltage lower than that of the first element. The second element is coupled to a control terminal and second and third terminals. The semiconductor switch also includes a flyback diode having a breakdown voltage substantially similar to that of the first element. A negative electrode of the first element is connected to a negative electrode of the second element and the flyback diode is connected in parallel between a positive terminal of the first element and a positive terminal of the second element. The control terminal for the first element and the control terminal for the second element are coupled to one or more control circuits independently of each other.

Abstract: According to one embodiment, a semiconductor switch includes a main element including a switching element and an antiparallel diode, and a reverse voltage application circuit. The reverse voltage application circuit includes an auxiliary electric-power supply, a high-speed free wheeling diode, an auxiliary element, and a capacitor. The high-speed free wheeling diode comprises a plurality of diodes connected in series.

Abstract: According to one embodiment, a semiconductor device includes a semiconductor circuit and an electric-power supply. The semiconductor circuit includes a main element including a switching element and an antiparallel diode, a reverse voltage application circuit including a high-speed free wheeling diode, a capacitor and an auxiliary element, a main element drive circuit, and an auxiliary element drive circuit. The electric-power supply is configured to supply electric-power to the capacitor, the main element drive circuit and the auxiliary element drive circuit, and has a voltage lower than the withstand voltage of the main element.

Abstract: According to one embodiment, a semiconductor switch includes a first element that includes a switching element and an anti-parallel diode. The switching element has a breakdown voltage and is coupled to a control terminal and second and third terminals. The semiconductor switch further includes a second element having a breakdown voltage lower than that of the first element. The second element is coupled to a control terminal and second and third terminals. The semiconductor switch also includes a flyback diode having a breakdown voltage substantially similar to that of the first element. A negative electrode of the first element is connected to a negative electrode of the second element and the flyback diode is connected in parallel between a positive terminal of the first element and a positive terminal of the second element. The control terminal for the first element and the control terminal for the second element are coupled to one or more control circuits independently of each other.