Abstract: According to one embodiment, an inrush current suppression circuit includes a normally-on transistor, a normally-off transistor connected in series with the normally-on transistor, a first drive circuit that drives the normally-on transistor, a second drive circuit that drives the normally-off transistor, a diode connected between an output of the first drive circuit and an output terminal of the normally-off transistor, a first power source smoothing circuit that performs smoothing of a source current to be supplied to the first drive circuit and the second drive circuit, and a switch circuit that switches connection/disconnection of a current path passing through the first power source smoothing circuit.

Abstract: According to one embodiment, a deterioration checking apparatus includes an inductor that is connected in series to a main current path of a MOS transistor to be checked, and forms a closed loop together with the MOS transistor when the MOS transistor is in an ON-state, a control circuit that controls ON/OFF of the MOS transistor, a current sensor that detects a current released from the inductor, and a calculation circuit that calculates an ON-resistance of the MOS transistor from an attenuation characteristic of a current released from the inductor when the MOS transistor is in an ON-state, and calculates a threshold voltage of the MOS transistor from an attenuation characteristic of a current released from the inductor when the MOS transistor is in an OFF-state. Therefore, it is possible to easily check a deterioration state of the MOS transistor.

Abstract: According to one embodiment, a signal processing circuit includes a first voltage setting circuit that sets a reference voltage on an input side of an isolator, a variable gain amplifier circuit that amplifies an output signal of the isolator, a DC offset adjustment circuit that adjusts an offset of the variable gain amplifier circuit, a second voltage setting circuit that sets a reference voltage on an output side of the isolator, and a control circuit that controls the DC offset adjustment circuit in response to a result of comparison of an output voltage of the variable gain amplifier circuit with an output voltage of the second voltage setting circuit.

Abstract: According to one embodiment, a signal processing circuit includes a first voltage setting circuit that sets a reference voltage on an input side of an isolator, a variable gain amplifier circuit that amplifies an output signal of the isolator, a DC offset adjustment circuit that adjusts an offset of the variable gain amplifier circuit, a second voltage setting circuit that sets a reference voltage on an output side of the isolator, and a control circuit that controls the DC offset adjustment circuit in response to a result of comparison of an output voltage of the variable gain amplifier circuit with an output voltage of the second voltage setting circuit.

Abstract: According to an embodiment, a transistor driver circuit includes a driving force limitation circuit and a delay-time adjustment circuit. The driving force limitation circuit operates to maintain a gate potential of a transistor to be driven at a driving force limitation potential when the transistor to be driven is driven. The driving force limitation potential corresponds to a threshold voltage of the transistor to be driven. The delay-time adjustment circuit operates to cause the gate potential to transition to the driving force limitation potential when the driving force limitation circuit is in operation.

Abstract: According to one embodiment, an inrush current suppression circuit includes a normally-on transistor, a normally-off transistor connected in series with the normally-on transistor, a first drive circuit that drives the normally-on transistor, a second drive circuit that drives the normally-off transistor, a diode connected between an output of the first drive circuit and an output terminal of the normally-off transistor, a first power source smoothing circuit that performs smoothing of a source current to be supplied to the first drive circuit and the second drive circuit, and a switch circuit that switches connection/disconnection of a current path passing through the first power source smoothing circuit.

Abstract: A semiconductor device that normally-off drives a first transistor that normally-on drives, the semiconductor device includes a first circuitry, a second circuitry, and a first diode. The first circuitry that is connected with a power supply voltage and a ground voltage, detects the power supply voltage, and outputs a transition state of the power supply voltage. The second circuitry that is connected with the power supply voltage, the ground voltage, the first circuitry, and a second transistor, and outputs a drive voltage of a second transistor connected in series with the first transistor, based on an output of the first circuitry. The first diode having an anode connected with a drive terminal of the first transistor and a cathode connected with an output terminal of the second transistor.

Abstract: A current detection circuit includes normally-on-type and a first normally-off-type switching elements with main current paths that are connected in series, and a second normally-off-type switching element that has a source and a gate that are connected to a source and a gate of the first normally-off-type switching element and a drain that is connected to a constant current source, and executes a division process by using drain voltages of the two normally-off-type switching elements.

Abstract: A semiconductor device that normally-off drives a first transistor that normally-on drives, the semiconductor device includes a first circuitry, a second circuitry, and a first diode. The first circuitry that is connected with a power supply voltage and a ground voltage, detects the power supply voltage, and outputs a transition state of the power supply voltage. The second circuitry that is connected with the power supply voltage, the ground voltage, the first circuitry, and a second transistor, and outputs a drive voltage of a second transistor connected in series with the first transistor, based on an output of the first circuitry. The first diode having an anode connected with a drive terminal of the first transistor and a cathode connected with an output terminal of the second transistor.

Abstract: According to an embodiment, a current detecting circuit includes: a normally-OFF type second switching element that is cascode-connected to a normally-ON type first switching element that includes a drain for outputting an output current; a normally-OFF type third switching element that is connected in parallel to the second switching element and whose drain is connected to a variable current source; and a comparison circuit that outputs a detection signal in accordance with a comparison result between a drain voltage of the second switching element and a drain voltage of the third switching element.

Abstract: According to one embodiment, a current detecting circuit includes: a normally-ON type first switching element that includes a drain, a source, and a gate; a normally-OFF type second switching element including a drain that is connected to the source of the first switching element, a source that is connected to the gate of the first switching element, and a gate; and a differential amplification circuit that outputs a voltage according to a voltage between the drain and the source of the second switching element.

Abstract: A current detection circuit includes normally-on-type and a first normally-off-type switching elements with main current paths that are connected in series, and a second normally-off-type switching element that has a source and a gate that are connected to a source and a gate of the first normally-off-type switching element and a drain that is connected to a constant current source, and executes a division process by using drain voltages of the two normally-off-type switching elements.

Abstract: A current detection circuit includes normally-on-type and a first normally-off-type switching elements with main current paths that are connected in series, and a second normally-off-type switching element that has a source and a gate that are connected to a source and a gate of the first normally-off-type switching element and a drain that is connected to a constant current source, and executes a division process by using drain voltages of the two normally-off-type switching elements.

Abstract: According to one embodiment, a deterioration checking apparatus includes an inductor that is connected in series to a main current path of a MOS transistor to be checked, and forms a closed loop together with the MOS transistor when the MOS transistor is in an ON-state, a control circuit that controls ON/OFF of the MOS transistor, a current sensor that detects a current released from the inductor, and a calculation circuit that calculates an ON-resistance of the MOS transistor from an attenuation characteristic of a current released from the inductor when the MOS transistor is in an ON-state, and calculates a threshold voltage of the MOS transistor from an attenuation characteristic of a current released from the inductor when the MOS transistor is in an OFF-state. Therefore, it is possible to easily check a deterioration state of the MOS transistor.

Abstract: According to one aspect of embodiments, a drive circuit of a normally-ON transistor includes: a normally-OFF transistor that includes a main current path connected in serial to a main current path of the normally-ON transistor; and a buffer circuit that supplies, to a gate of the normally-ON transistor, a control signal for controlling turning ON and OFF of the normally-ON transistor, whose high-voltage side and low-voltage side are biased by a bias voltage supplied from a power source unit.

Abstract: According to one embodiment, a drive control circuit includes a first transistor that supplies a current to a gate of an output transistor in response to a drive signal, a second transistor that supplies a current to a capacitor in response to the drive signal, a comparison circuit that compares a gate voltage of the output transistor and a voltage of the capacitor, a control signal generation circuit that generates a control signal in response to an output signal of the comparison circuit and the drive signal, and a third transistor that supplies a current to a gate of the output transistor in response to the control signal.

Abstract: A semiconductor device that normally-off drives a first transistor that normally-on drives, the semiconductor device includes a first circuitry, a second circuitry, and a first diode. The first circuitry that is connected with a power supply voltage and a ground voltage, detects the power supply voltage, and outputs a transition state of the power supply voltage. The second circuitry that is connected with the power supply voltage, the ground voltage, the first circuitry, and a second transistor, and outputs a drive voltage of a second transistor connected in series with the first transistor, based on an output of the first circuitry. The first diode having an anode connected with a drive terminal of the first transistor and a cathode connected with an output terminal of the second transistor.

Abstract: According to one embodiment, a current detecting circuit includes: a normally-ON type first switching element that includes a drain, a source, and a gate; a normally-OFF type second switching element including a drain that is connected to the source of the first switching element, a source that is connected to the gate of the first switching element, and a gate; and a differential amplification circuit that outputs a voltage according to a voltage between the drain and the source of the second switching element.

Abstract: A semiconductor device that normally-off drives a first transistor that normally-on drives, the semiconductor device includes a first circuitry, a second circuitry, and a first diode. The first circuitry that is connected with a power supply voltage and a ground voltage, detects the power supply voltage, and outputs a transition state of the power supply voltage. The second circuitry that is connected with the power supply voltage, the ground voltage, the first circuitry, and a second transistor, and outputs a drive voltage of a second transistor connected in series with the first transistor, based on an output of the first circuitry. The first diode having an anode connected with a drive terminal of the first transistor and a cathode connected with an output terminal of the second transistor.

Abstract: According to one embodiment, a current detecting circuit includes: a normally-ON type first switching element that includes a drain, a source, and a gate; a normally-OFF type second switching element including a drain that is connected to the source of the first switching element, a source that is connected to the gate of the first switching element, and a gate; and a differential amplification circuit that outputs a voltage according to a voltage between the drain and the source of the second switching element.