Various embodiments may relate to a synchronous rectifier including at least one rectifier cell, to which power is supplied via a secondary winding of a transformer arranged between the input connections of the synchronous rectifier. The rectifier cell comprises a bipolar main switch operated in the inverse mode, wherein an energy store is provided in the base line of the bipolar main switch, which energy store, in conjunction with an auxiliary switch which is concomitantly controlled by the relevant secondary winding for the bipolar main switch, ensures that the main switch is switched off prior to the end of the inverse phase.

Disclosed is an electronic drive circuit and a drive method. The drive circuit includes an output; a first output transistor comprising a control node and a load path, wherein the load path is coupled between the output and a first supply node; a voltage regulator configured to control a voltage across the load path of the first output transistor; and a first driver configured to drive the first output transistor based on a first control signal.

A bi-directional voltage converter of a smart card includes switching elements connected between an input node and an output node and a start-up transistors whose channel width over channel length is smaller than a channel width over channel length of the switching element. The bi-directional voltage converter stores a driving voltage applied to an output node in a storage capacitor during a booting operation and provides the voltage stored in the storage capacitor to an input node. The bi-directional voltage converter may boost another driving voltage at the input node step-wisely and may perform bi-directional voltage converting with reduced occupied area and high efficiency.

A method and apparatus is disclosed for maintaining a stable power supply to a circuit when activating/deactivating a switch in order to accelerate the switching time of the switch. The gate of a FET is coupled to a switch driver. The switch driver is powered by a positive power supply and a negative power supply. When the switch is to be activated/deactivated, the gate is first coupled to a reference potential (i.e., ground) for a “reset period” to reduce any positive/negative charge that has been accumulated in the FET. At the end of the reset period, the gate is then released from the reference potential and the switch driver drives the gate to the desired voltage level to either activate or deactivate the switch.

A drive device driving a power converter that includes a switching element formed from a wide bandgap semiconductor, includes a PWM-signal output unit that generates a drive signal that drives the switching element with PWM; an on-speed reducing unit that, when the switching element is changed from off to on, reduces a change rate of the drive signal; and an off-speed improving unit that, when the switching element is changed from on to off, draws charge from the switching element at a high speed and with a charge drawing performance higher than that at a time when the switching element is changed from off to on.

A switch device includes a first radio-frequency (RF) terminal, a second RF terminal, a first transistor, a second transistor, and a variable resistance element. The first transistor includes a first terminal coupled to the first RF terminal, a second terminal, and a control terminal coupled to a control signal terminal providing a control signal. The second transistor includes a first terminal coupled to the second terminal of the first transistor, a second terminal coupled to the second RF terminal, and a control terminal. The variable resistance element is coupled between the second terminal of the first transistor and a bias voltage terminal. When the first transistor and the second transistor are in a transient state, the variable resistance element provides a lower resistance. When the first transistor and the second transistor are in an ON state, the variable resistance element provides a higher resistance.

A power conversion apparatus includes a semiconductor module including a semiconductor device and a control circuit unit controlling the semiconductor module. The semiconductor module has main and subsidiary semiconductor devices connected in parallel. The control circuit unit performs control such that the subsidiary semiconductor device is turned on after the main semiconductor device is turned on, and the main semiconductor device is turned off after the subsidiary semiconductor device is turned off. The control circuit unit performs control such that, one of the turn-on and turn-off switching timings has a switching speed faster than that of the other of the switching timings. The semiconductor module is configured such that, at a high-speed switching timing, an induction current directed to turn off the subsidiary semiconductor device is generated in a control terminal of the subsidiary semiconductor device depending on temporal change of a main current flowing to the main semiconductor device.

A gate driving circuit of embodiments is provided with a first transistor which controls a gate-on voltage applied to a gate electrode of a switching device, a second transistor which controls a gate-off voltage applied to the gate electrode of the switching device, a driving logic circuit which controls turn-on/turn-off of the first and second transistors, a first power source which supplies the gate-on voltage to the gate electrode when the first transistor is turned on, a second power source which supplies the gate-off voltage to the gate electrode when the second transistor is turned on, a first gate resistance variable circuit in which a plurality of field effect transistors is connected in parallel, a second gate resistance variable circuit in which a plurality of field effect transistors is connected in parallel, and a gate resistance control circuit which controls gate voltages of a plurality of field effect transistors.

A power conversion circuit is mounted in a vehicle and controls an output torque of the rotating machine based on a requested command torque. A driving apparatus of a switching element controls a current flowing to the rotating machine. The driving apparatus sets at least one of a turn-on speed and a turn-off speed for the switching element to a plurality of switching speeds that are discretely determined, based on a parameter that is correlated with the output torque and has a controllable value. The driving apparatus turns on or off the switching element at the switching speeds. The switching speeds are allocated to the respective magnitudes of the parameter at uneven intervals, and determined such that the number of allocated switching speeds is greater in a range in which an occurrence frequency of the parameter is high, compared to a range in which the occurrence frequency is low.

A power conversion circuit is mounted in a vehicle and controls an output torque of the rotating machine based on a requested command torque. A driving apparatus of a switching element controls a current flowing to the rotating machine. The driving apparatus sets at least one of a turn-on speed and a turn-off speed for the switching element to a plurality of switching speeds that are discretely determined, based on a parameter that is correlated with the output torque and has a controllable value. The driving apparatus turns on or off the switching element at the switching speeds. The switching speeds are allocated to the respective magnitudes of the parameter at uneven intervals, and determined such that the number of allocated switching speeds is greater in a range in which an occurrence frequency of the parameter is high, compared to a range in which the occurrence frequency is low.