Kabushiki Kaisha Toshiba

Kimihiro Hoshi

Takashi Shinohe

Masakazu Yamaguchi

Tsuneo Ogura

Takeo Kanai

In a gate circuit having a turn-off gate circuit composed of: OFF gate power source E,of which one terminal is connected to the emitter of semiconductor switching element 81, and switch SW,that connects the other terminal of OFF gate power source E,and the gate of semiconductor switching element S,via resistor R,, the gate circuit is provided with second switch SW,that connects the other terminal of OFF gate power source E,and the gate of semiconductor switching element S,By closing second switch SW,at the timing at which the turn-off operation is completed, it will connect to OFF gate power source E,without passing through a resistor.

Gate circuit

A semiconductor protection device is used to suppress a surge voltage to a preset value or less, the surge voltage being caused at each turn-OFF time of 50 Hz to 20 kHz of a main IGBT functioning as a switch of a power converting system. The semiconductor protection device includes a protection IGBT for forming a bypass connected in parallel with the main IGBT and an electric field sensing element connected in a reverse direction between the collector of the main IGBT and the gate of the protection IGBT. When the surge voltage exceeds a preset value which is a breakdown voltage of the electric field sensing element, the protection IGBT is turned ON so as to cause a current generated by energy of the surge voltage to be bypassed.

Semiconductor protection device and power converting system

A semiconductor device comprises a voltage-driven switching element having a cathode and an anode, in which a voltage is to be applied between the cathode and anode, a power-supply circuit connected between the cathode and anode of the voltage-driven switching element and comprising capacitors, resistors and a reverse current-low preventing diode, for generating an intermediate voltage, a charging switching element for charging a gate of the voltage-driven switching element, using the intermediate voltage generated by the power-supply circuit, a discharging switching element for discharging the gate of the voltage-driven switching element, and a photovoltaic element for generating a photovoltaic power to control to drive the charging switching element and the discharging switching element.

Power supply circuit

A semiconductor device includes a voltage-driven switching element having a cathode and an anode, in which a voltage is to be applied between the cathode and anode, a power-supply circuit connected between the cathode and anode of the voltage-driven switching element and comprising capacitors, resistors and a reverse current-low preventing diode, for generating an intermediate voltage, a charging switching element for charging a gate of the voltage-driven switching element, using the intermediate voltage generated by the power-supply circuit, a discharging switching element for discharging the gate of the voltage-driven switching element, and a photovoltaic element for generating a photovoltaic power to control to drive the charging switching element and the discharging switching element.

Driving circuit for driving a semiconductor device at high speed and

A power conversion system including, a series circuit of an upper arm and a lower arm connected between a positive terminal and a negative terminal of a DC power source. Each of the upper and lower arms is composed of a power device having a large dv/dt withstand value and a first snubber circuit connected in parallel with the power device. Each of the first snubber circuits is composed of at least a first capacitor having a fixed capacitance. The power conversion system further includes two second snubber circuits, each composed of a series circuit of a second diode and a second capacitor, connected in parallel with one of the upper and lower arms, and a second resistor connected between a connecting point of the second diode and the second capacitor and one of the negative and positive terminals of the DC power source, respectively.

Growing community of inventors

Tokyo, Japan

Kimihiro Hoshi