Mitsubishi Electric Corporation

Yo Habu

Akihisa Yamamoto

Masahiro Yamamoto

Mitsutaka Hano

During an ON period of a high breakdown voltage switch provided within an ON period of a semiconductor switching element, a detection circuit outputs to a predetermined node a voltage obtained by dividing an inter-terminal voltage by a plurality of resistor elements. A voltage comparison circuit outputs a detection signal indicating whether or not the inter-terminal voltage is greater than a predetermined determination voltage based on a comparison between the voltage of the predetermined node and a predetermined DC voltage. The high breakdown voltage switch has a breakdown voltage greater than a potential difference between a high potential and a low potential during an OFF period.

Semiconductor device

The detection circuit includes a current source and a resistor element which are connected in series via a first node between a positive electrode and a negative electrode of a switching element which is turned on and off by a driving circuit. The voltage comparator outputs a detection signal indicating a comparison result between an input DC voltage and the voltage of the first node. The DC voltage and the electric resistance value of the resistor element are set in such manner that when an inter-electrode voltage between the positive electrode and the negative electrode becomes higher than a predefined determination voltage, the voltage of the first node is higher than the DC voltage. The detection circuit and the voltage comparator are mounted on the same integrated circuit constituting the semiconductor device.

The object is to provide a technology enabling appropriate driving of an IGBT. A driving circuit is a driving circuit that drives an IGBT by controlling the gate voltage of the IGBT, and includes a first charging capability and a second charging capability. The first charging capability increases the gate voltage up to a threshold voltage of the IGBT, and a second charging capability increases the gate voltage beyond the threshold voltage. An increase in the gate voltage with the first charging capability per unit time is higher than an increase in the gate voltage with the second charging capability per unit time.

Driving circuit

A current to be supplied to a load driven by the current is linearly controlled in accordance with a voltage. A voltage-current converter according to the present invention includes a differential amplifier, a first current mirror, and a voltage setting unit. The differential amplifier receives an input voltage from an input terminal and outputs a voltage in accordance with a difference between the input voltage and a threshold voltage. The first current mirror receives the voltage from the differential amplifier and outputs an output current to an output terminal. The voltage setting unit sets the threshold voltage.

Voltage-current converter and load driver

The device for driving the semiconductor element is provided with a drive circuit section, a charging circuit section and a shutting circuit section. The charging circuit section is electrically connected to an external circuit provided with a diode and a capacitive element. The semiconductor element has a first electrode, a second electrode and a control terminal. The cathode of the diode is connected to the first electrode. One of two terminals of the capacitive element is connected to the cathode of the diode, and the other terminal is connected to the second electrode. The charging circuit section enables the capacitive element to be charged at a higher rate after a timed point at which the voltage on the capacitive element becomes equal to a saturation voltage in a case where the input signal is an on-signal.

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Tokyo, Japan

Yo Habu