In a semiconductor device in the related art, it has been necessary to match the threshold voltage of a power element with the circuit operation of a gate driver; accordingly, it has been difficult to realize the operation of the gate driver most appropriate for the employed power element. According to one embodiment, when a power element is turned off, the semiconductor device monitors the collector voltage of the power element, and increases the number of NMOS transistors that draw out charges from the gate of the power element in a period until the collector voltage becomes lower than the pre-set determination threshold, rather than in the period after the collector voltage becomes lower than the determination threshold.

An apparatus is adapted to drive an insulating gate-type semiconductor element by a first control voltage and a second control voltage, that are supplied to a first insulating gate and a second insulating gate, respectively, and includes a first noise filter inputting a signal about current that passes through the insulating gate-type semiconductor element, a first comparator making a comparison between an output signal of the first noise filter and a first reference signal and outputting a first comparison result, a first control voltage output circuit, and a second control voltage output circuit, the second control voltage output circuit being adapted to reduce the second control voltage when it is determined from the first comparison result that overcurrent passes through the insulating gate-type semiconductor element, the first control voltage output circuit being adapted to reduce the first control voltage after the second control voltage is reduced.

A control board of a power conversion device, the control board includes a board main body, a plurality of drive circuits, a power source control circuit, an insulation region, a plurality of insulation transformers, and a connecting line that electrically connects the plurality of insulation transformers and the power source control circuit to each other, and at least a part of which extends in a region in inner layers of the board main body that overlaps the insulation region when viewed in a perpendicular direction with respect to the surface of the board main body.

Devices and methods are provided, which detect a short circuit condition related to a semiconductor switch. A short circuit condition may be determined when a control signal of the switch exceeds a first reference, and a change of load current of the switch exceeds a second reference.

Devices and methods are provided, which detect a short circuit condition related to a semiconductor switch. A short circuit condition may be determined when a control signal of the switch exceeds a first reference, and a change of load current of the switch exceeds a second reference.

A switching element driving circuit includes a current detection unit that outputs a driving stop signal based on a level of current flowing through the switching element, and first and second control elements each connected to a control terminal of the switching element. A comparator controls the first control element based on a result of comparison of an output voltage of the driving circuit main unit with a first reference voltage. A differential amplifier drives the second control element in accordance with a voltage difference between the output voltage of the driving circuit main unit and a second reference so as to maintain the output voltage equal to the second reference voltage. An operation stopping unit stops the comparator and the differential amplifier to drive the first and second control elements, respectively, in response to the driving stop signal.

There are provided methods and systems for operating insulated gate bipolar transistors (IGBTs). For example, there is provided a method that can include detecting a desaturation condition in an IGBT and initiating a turn off procedure when desaturation is detected. The turn off procedure can include holding a gate of the IGBT at at least one voltage level intermediate between a positive rail voltage and a negative rail voltage of an operational range of the IGBT.

A semiconductor device includes a switching element chip, in which a switching element is formed; a first sensing element, which is provided in the switching element chip and is configured to detect first output voltage based on an operating current of the switching element; a second sensing element, which is provided outside the switching element chip and is configured to detect second output voltage based on the operating current of the switching element; and a control circuit, which detects the operating current based on the second output voltage and interrupts the switching element, based on the first output voltage of the first sensing element and the detected operating current, when the switching element is overheated.

In a general aspect, an apparatus can include a temperature measurement circuit configured to produce a first signal indicating a first operating temperature of a first semiconductor device and a temperature comparison circuit operationally coupled with the temperature measurement circuit. The temperature comparison circuit can be configured to compare the first signal with a second signal indicating a second operating temperature of at least a second semiconductor device and produce a comparison signal indicating whether the indicated first operating temperature is higher, lower or equal to the indicated second operating temperature. The apparatus can also include an adjustment circuit configured to adjust operation of the first semiconductor device based on the comparison signal.

A gate drive circuit includes a driver for driving a gate of a switching element, a peak voltage detector, and a drive capacity calculator. The peak voltage detector detects a peak voltage at a main terminal of the switching element when the switching element is OFF. The drive capacity calculator calculates a voltage difference value between the detected peak voltage and an allowable voltage value at the main terminal of the switching element, where the allowable voltage is based on the specifications of the switching element. The drive capacity calculator changes a drive capacity of the driver to gradually decrease the difference between the detected peak voltage and the allowable voltage.