A first clamp circuit (4) clamps a voltage between a gate and a first terminal of a switching device (Q1) to equal to or lower than a first clamp voltage. A control circuit (2) controls the switching device (Q1) and includes a driving unit (5) driving the switching device (Q1), an abnormality detecting unit (9) stopping the driving unit (5) upon detection of an abnormality in operation, and a second clamp circuit (10). The second clamp circuit (10) clamps the voltage between the gate and the first terminal to equal to or lower than a second clamp voltage which is lower than the first clamp voltage when the abnormality detecting unit (9) stops the driving unit (5).

A drive circuit configured to apply a slew rate controlled drive signal to the control terminal of a power transistor. The drive circuit may be part of a system that includes one or more sub-circuits in which each sub-circuit includes a regulation loop, a matched replica of the power transistor and regulated voltage node. The voltage reference voltage for each sub-circuit connects to the control terminal of the power switch through a buffer circuit to apply a sequence of voltages to the control terminal of the power switch. A switching controller circuit may manage the operation of the one or more sub-circuits so that the drive circuit may output a precisely controlled voltage profile to the control terminal of the power transistor. The circuit may include a second buffer under the control of the switching controller circuit to further manage the operation of the power transistor.

In recent years, an improvement in detection accuracy of an overcurrent is desired. An overcurrent detection device is provided, which includes a gate current detection unit that detects whether a gate current flowing to a semiconductor element is equal to or above a reference gate current; a sense current detection unit that detects whether a sense current flowing through a sense-emitter terminal of the semiconductor element is equal to or above a reference sense current; and an adjustment unit that decreases a detected value of the sense current relatively to the reference sense current if the gate current is equal to or above the reference gate current.

A gate driver circuit receiving an input control signal and providing a voltage at a gate terminal of a semiconductor switching device (e.g., an IGBT) may include: (i) a first voltage source providing a first voltage; (ii) a second voltage source providing a second voltage, wherein the first voltage is higher than the second voltage; and (iii) a selector circuit selecting, based on the input control signal's logic state, either the first voltage or the second voltage to be placed on the gate terminal of the semiconductor switching device.

-- The present disclosure relates to an IGBT driving circuit and a power conversion device. The IGBT driving circuit includes a driving chip with a first driving signal port (Vo); a driving resistor adjustment circuit connected between the first driving signal port (Vo) and a gate (G) of an IGBT, a driving resistor formed by the driving resistor adjustment circuit being adjustable in size; a peak voltage detection circuit connected to the gate (G) of the IGBT which is conductive to the first driving signal port (Vo), the peak voltage detection circuit being configured to monitor whether a peak voltage occurs when the IGBT is turned off; and a resistor adjustment control circuit connected between the peak voltage detection circuit and the driving resistor adjustment circuit and configured to reduce a resistor formed by the driving resistor adjustment circuit when the peak voltage is monitored when the IGBT is turned off.

A switching circuit has a primary MOSFET switch connected between first and second terminals that are connected to a power line and a load represented as a resistance and inductance. The primary switch is operable by primary control commands to assume a conductive or non-conductive state. Four protection branches are connected in parallel with the primary switch, each having a series connected resistive element and a secondary MOSFET switch operable by branch control commands received at branch command terminals to assume a conductive or non-conductive state. A timing circuit applies branch turn off control commands in sequence to the branch command terminals, each delayed by a different predetermined time interval relative to when a primary turn off control command is applied to the primary switch.

A semiconductor device including: an output element connected to a load and configured to perform switching to operate the load; a drive circuit configured to output a drive signal to thereby cause the output element to perform the switching; an external terminal configured to be connected to a constant current source that is external to the semiconductor device, and to receive a constant current from the constant current source; a temperature sensor connected to the external terminal, and configured to operate with the constant current, detect a temperature of the output element, and output a temperature detection value; a temperature state detection circuit configured to output a temperature state of the output element, based on a result of comparing the temperature detection value with a reference threshold; and an abnormal level notification circuit configured to send out a notification upon determining that the temperature state is at an abnormal level.

A gate drive circuit 22A, in order to cause an IGBT 211a in a semiconductor elements 21u to switch to the ON state according to the signal level of an input signal SinUH, includes a constant current supply unit 223uA configured to supply constant current to the gate G of the IGBT 211a, a switching signal input terminal Tsw4 to which a switching signal Ssw4 is input, a signal level determination unit 226uA configured to determine a signal level of the switching signal Ssw4, and a drive capability switching unit 224uA configured to, by changing a current amount of constant current output from the constant current supply unit 223uA, based on a determination result in the signal level determination unit 226uA and a signal level of the input signal SinUL, switch the drive capability of the constant current supply unit 223uA.

The present invention relates to a method for short-circuit detection by saturation detection in power semiconductor switches and to a corresponding device. A reference voltage (U.sub.ref) is provided as a function of a supply voltage (U.sub.VDD) of a power semiconductor switch. A differential voltage (U.sub.diff) is generated from the difference of a voltage drop (U.sub.Δ) of a load path of the power semiconductor switch and the provided reference voltage (U.sub.ref). The generated differential voltage (U.sub.diff) is compared with a predetermined threshold voltage (U.sub.lim). A short-circuit current in the load path of the power semiconductor switch is detected when the differential voltage (U.sub.diff) exceeds the threshold voltage (U.sub.lim). In this case, the power semiconductor switch is opened.

A two-terminal electrical protective device operates by harvesting energy from a small but non-zero voltage drop across a closed solid-state switch. From a default, open-circuit state, the device is remotely triggered by an AC signal to enter the desired conductive state. Power scavenged by an energy harvesting circuit while the device is in the conductive state, powers a gate drive circuit to hold the device in the conductive state for as long as current flows. When current stops, the device returns to the default open-circuit state.