A device includes a first switch and a first diode connected in parallel between a midpoint and a first terminal of the hybrid power device, a second switch and a second diode connected in parallel between the midpoint and a second terminal of the hybrid power device, a third switch coupled between the first terminal and the second terminal, and a third diode connected between the first terminal and the second terminal.

A power stage includes a power transistor controlled via a driver, the power transistor comprising three terminals, including a collector c, an emitter e and a gate g linked to the driver, the power stage comprising a detection device for detecting a short-circuit current cc between the collector c and the emitter e, the detection device comprising a voltage sensor capable of detecting a voltage Vge at the gate g of the power transistor outside of a predefined voltage range.

A semiconductor switch drive device (3) includes a drive unit (10), a power supply unit (20), a switch (39), and a control unit (50). The drive unit (10) supplies a control signal to a semiconductor switch (Q) of a main circuit (2) and drives the semiconductor switch (Q). The power supply unit (20) supplies electric power to the drive unit (10). The switch (39) cuts off supply of electric power to the power supply unit (20) by detecting or controlling an overvoltage state on a primary side of the power supply unit (20). The control unit (50) switches a conductive state of the switch (39) on the basis of a voltage of a control terminal of the semiconductor switch (Q).

It is an object of the present invention to provide a buffer circuit that reduces a reverse voltage applied to transistors being a complementary pair during turn-on and turn-off. A buffer circuit is a buffer circuit that turns on and turns off a switching element and includes a drive-side element that has an end connected to a base of a drive transistor and a sink-side element that has an end connected to a base of a sink transistor. The drive-side element and the sink-side element are respectively a drive-side diode and a sink-side diode, or a drive-side capacitor and a sink-side capacitor.

This disclosure relates to monitoring the condition of electrical/electronic switches over time by monitoring the impedance of the switch. The condition of switches can degrade as they age, which can reduce their performance and may ultimately lead to failure. In many applications, particularly high-voltage applications, the reliable operation of switches may be very important and failures can present a safety risk and cause costly unscheduled system downtime for repairs. It has been realised that as the condition of switches change, their impedance changes, so monitoring the impedance can give a good indication of the condition of the switch, enabling potential faults/failures to be identified early and acted upon pre-emptively.

The invention relates to a method (10) and to a device (ALE) for operating a switching element (LHS), said method comprising the following steps: a temperature (Tmp) of the switching element (LHS) is determined (22) and said switching element (LHS) is operated (26) in accordance with the determined temperature (TmP).

Overload detection and protection for power switch circuits. For circuits with faster switching speed, fast fault detection and response to a detected overload condition may be desirable. Detection circuitry may monitor a voltage on the control terminal of one or more power switches. Based on empirical measurements, in an overload condition of a power switch circuit, e.g., a half-bridge circuit, the voltage at the control terminal may increase, and in some examples, increase to a magnitude that is greater than a supply voltage. A comparator may detect a voltage increase that exceeds a voltage magnitude threshold, output an indication to control circuitry for the power switch circuit, and the control circuitry may take action to protect the rest of the circuitry, such as reduce voltage or shut off the power switch circuit.

In order to obtain a drive circuit of a power semiconductor device capable of making a fast response to a voltage fluctuation dV/dt and preventing a malfunction of the power semiconductor device while suppressing power consumption with a simple circuit configuration, a control circuit controlling ON and OFF switching of the power semiconductor device, a DC power supply supplying a voltage between control terminals of the power semiconductor device, and a switching element connected between the control terminals of the power semiconductor device are provided. The switching element turns ON in a case where a power supply voltage of the DC power supply drops or in a case where the voltage between the control terminals of the power supply device increases in a state where the power supply voltage of the DC power supply has dropped, and thereby causes a short-circuit between the control terminals of the power semiconductor device.

Switch modules, driver circuits for switch modules and corresponding methods are provided. In an implementation, a switch module includes a transistor switch including a control terminal, a first load terminal and a second load terminal, and a short circuit detection circuit configured to detect a short circuit state between the first load terminal and the second load terminal and to electrically couple the control terminal and the first load terminal in response to detecting the short circuit state. The short circuit detection circuit is supplied by a voltage between the control terminal and the first load terminal.

A driver circuit (101) is connected to a control terminal of a semiconductor switching element (1). The driver circuit (101) includes an input circuit (3) connected to an input terminal (50), and an output control circuit (4) connected to the input circuit (3). A pulse signal output from the output control circuit (4) is input to a dead time adjustment circuit (13). The dead time adjustment circuit (13) includes a delay circuit which can delay the rising edge and the falling edge of the pulse signal output from the output control circuit (4) on the basis of signals from temperature analog output circuits (11) and (12). An output from the dead time adjustment circuit (13) is input to the drive circuit (5). The drive circuit (5) outputs a drive signal to an output terminal (51) of the driver circuit (101).