A drive circuit of a voltage-controlled power semiconductor element, including first to fourth switching elements, first and second delay circuits, an overcurrent detection circuit, a slow shutdown detection circuit and a flip-flop. The first switching element turns on upon receiving an off signal. The second switching element is turned on by the first delayed signal generated by the first delay circuit. The third switching element turns on upon receiving a second delayed signal generated by the second delay circuit through the flip-flop. The fourth switching element is turned on by the slow shutdown detection signal generated by the slow shutdown detection circuit. The first to fourth switching elements extract electric charges from the gate terminal of the voltage-controlled power semiconductor element, with first to fourth extracting capabilities, respectively. The first and fourth extracting capabilities are larger than the third extracting capability and smaller than the second extracting capability.

A hybrid switch for a power converter and a method of operating said hybrid switch, the hybrid switch comprising: at a minimum a first and a second element comprising one or more switching devices of a first semiconductor type, and at a minimum a third element comprising one or more switching devices of a second semiconductor type, wherein the second semiconductor type is different from the first semiconductor type, and wherein each element is independently configurable and connected to a separate respective control terminal; and, a controller connected to the control terminals, wherein the controller is configured to control each element independently through each respective control terminal, and wherein the controller is further configured to activate elements based on a measured or estimated current and/or power as required by an operating condition of the converter.

A hybrid switch for a power converter and a method of operating said hybrid switch, the hybrid switch comprising: at a minimum a first and a second element comprising one or more switching devices of a first semiconductor type, and at a minimum a third element comprising one or more switching devices of a second semiconductor type, wherein the second semiconductor type is different from the first semiconductor type, and wherein each element is independently configurable and connected to a separate respective control terminal; and, a controller connected to the control terminals, wherein the controller is configured to control each element independently through each respective control terminal, and wherein the controller is further configured to activate elements based on a measured or estimated current and/or power as required by an operating condition of the converter.

An electric working machine according to one aspect of the present disclosure comprises a motor, a rectifier circuit, a capacitor, a series switching element, a resistive element, a drive circuit, a peak voltage value acquirer, and a controller. The capacitor smooths power rectified by the rectifier circuit. The series switching element is coupled in series with the capacitor. The resistive element is coupled in parallel with the series switching element. The controller brings the series switching element into conduction in a case where AC power is inputted to the rectifier circuit and where a specified conducting condition based on a peak voltage value acquired by the peak voltage value acquirer is satisfied.

An electric working machine according to one aspect of the present disclosure comprises a motor, a rectifier circuit, a capacitor, a series switching element, a resistive element, a drive circuit, a peak voltage value acquirer, and a controller. The capacitor smooths power rectified by the rectifier circuit. The series switching element is coupled in series with the capacitor. The resistive element is coupled in parallel with the series switching element. The controller brings the series switching element into conduction in a case where AC power is inputted to the rectifier circuit and where a specified conducting condition based on a peak voltage value acquired by the peak voltage value acquirer is satisfied.

A semiconductor element drive device is provided to solve a problem that because a case of a change in the temperature of the semiconductor element or a current flowing through the semiconductor element is not take into consideration, switching loss and noise cannot be reduced sufficiently. In accordance with input sensing information (temperature T, current I), a timing control unit 3 outputs a delay signal Q to control timing of driving a current increasing circuit 5 so that a reduction of switching loss of an IGBT 101 is maximized. When the IGBT 101 is in turn-on mode or turn-off mode, the current increasing circuit 5 outputs a drive signal in response to the delay signal Q delayed by a given time from output of the drive instruction signal P. In this way, the current increasing circuit 5 increases the current that causes the gate capacitor of the IGBT 101 to be charged/discharged in response to the delay signal Q, thereby increasing a switching speed to reduce switching loss.

A semiconductor element drive device is provided to solve a problem that because a case of a change in the temperature of the semiconductor element or a current flowing through the semiconductor element is not take into consideration, switching loss and noise cannot be reduced sufficiently. In accordance with input sensing information (temperature T, current I), a timing control unit 3 outputs a delay signal Q to control timing of driving a current increasing circuit 5 so that a reduction of switching loss of an IGBT 101 is maximized. When the IGBT 101 is in turn-on mode or turn-off mode, the current increasing circuit 5 outputs a drive signal in response to the delay signal Q delayed by a given time from output of the drive instruction signal P. In this way, the current increasing circuit 5 increases the current that causes the gate capacitor of the IGBT 101 to be charged/discharged in response to the delay signal Q, thereby increasing a switching speed to reduce switching loss.

An integrated circuit for controlling an ignition system including a coil. The integrated circuit includes a transistor configured to control a current flowing through the coil, a first line coupled to a control electrode of the transistor, a second line coupled to an electrode of the transistor on the ground side thereof, a control circuit configured to control on and off of the transistor based on a voltage level of the first line, and a Zener diode having a cathode coupled to the first line and an anode coupled to the second line. The Zener diode has such a capacitance that, when a first signal, and a second signal of a higher frequency, are inputted to the first line, the control circuit controls the on and off of the transistor in response to the first signal irrespective of the second signal.

An integrated circuit for controlling an ignition system including a coil. The integrated circuit includes a transistor configured to control a current flowing through the coil, a first line coupled to a control electrode of the transistor, a second line coupled to an electrode of the transistor on the ground side thereof, a control circuit configured to control on and off of the transistor based on a voltage level of the first line, and a Zener diode having a cathode coupled to the first line and an anode coupled to the second line. The Zener diode has such a capacitance that, when a first signal, and a second signal of a higher frequency, are inputted to the first line, the control circuit controls the on and off of the transistor in response to the first signal irrespective of the second signal.

In one aspect, a quasi-resonant turn-off circuit is provided. The quasi-resonant turn-off circuit is couplable in parallel with a pair of anti-parallel thyristors. The quasi-resonant turn-off circuit includes a resonant capacitor and an energy recovery circuit. The resonant capacitor is configured to supply a charge to the pair of anti-parallel thyristors to decrease a turn-off time of the pair of anti-parallel thyristors. The energy recovery circuit is configured to recharge the resonant capacitor using remnant energy left in parasitic inductances coupled to the quasi-resonant turn-off circuit after the pair of anti-parallel thyristors is off.