In order to balance the thermal stress of the switches (S1-S4) of the two legs of an inverter full bridge (4), the driving signals are generated using an up-down counter having a modulation period T.sub.mod of twice the period T of the input voltage (Vin). The up-down counter has a first compare value (41) of D/4 and a second compare value (42) of (2+D)/4, where D is the duty cycle and where the second half bridge is phase shifted by the period T.

A direct-current power supply includes: a rectifier circuit in which switching elements are bridge-connected; a reactor; a gate circuitry that drives the switching elements; and a gate circuitry that drives the switching elements. A connection point between the switching element and the switching element is connected to an alternating-current power supply via the reactor, and a connection point between the switching element and the switching element is connected to the alternating-current power supply without via the reactor. A time during which the gate circuitry turns on the switching elements is longer than a time during which the gate circuitry turns on the switching elements.

Provided is a switch driving apparatus including a controller configured to individually control a first switch element and a second switch element included in a bidirectional switch, in which, when the controller stops on/off drive of the bidirectional switch, the controller turns off both the first switch element and the second switch element and then temporarily turns on one of the first switch element and the second switch element for a predetermined on time period.

A wiring device including a first printed circuit board (PCB) that includes a first direct current (DC) output port and a second DC output port. The wiring device further includes a second PCB electrically connected with the first PCB, the second PCB including a planar transformer integrated with a surface of the second PCB and configured to output power at one or more DC voltage levels, a switch connected to the planar transformer, and a microcontroller. The microcontroller includes an electronic processor and is configured to control delivery of power from the planar transformer to at least one of the first DC output port and the second DC output port using the switch. The switch may have a Gallium Nitride (GaN) chemistry or a Silicon Carbide (SiC) chemistry.

A half-bridge power supply comprises: a first switch electrically connected to an energy source and to a load; a second switch electrically connected to the energy source and to the load; and circuitry electrically connected to the first and second switches and configured to provide a dynamic dead time for the half-bridge power supply based on one of the first and second switches being turned off having forward current.

In a DC/DC converter, in first power transmission in which power is transmitted from a first DC power source to a second DC power source, on/off drive of a positive electrode-side switching element and a negative electrode-side switching element is stopped in a third bridge circuit on the power-receiving side. When a power transmission amount by the first power transmission is smaller than a first reference value, a control circuit lowers the switching frequency of the switching elements of a first bridge circuit and a second bridge circuit on the power-transmitting side and a fourth bridge circuit on the power-receiving side, compared with when the power transmission amount is equal to or greater than the first reference value.

An active clamp flyback (ACF) converter can be used to convert AC voltages to DC voltages and offers the ability to reuse leakage energy and a negative magnetizing current to achieve zero-volt-switching. The leakage energy can vary with system design and therefore may be difficult to control, but the negative magnetizing current can be controlled by adjusting a switching frequency of the ACF converter. The adjustment can be determined by comparing the negative magnetizing current to a threshold. Using a fixed threshold may not be optimal because variations in system operating conditions, such as load current, line voltage, and output voltage, can affect the amount of negative magnetizing current required for zero-volt-switching (i.e., can affect the threshold). Additionally, a range of possible switch technologies can affect the threshold. The present disclosure describes an adaptable threshold for a variable frequency ACF converter that allows for efficient switching.

A power supply system 1 includes: a variable voltage power supply 7 that outputs power of a variable voltage from a pair of secondary-side input/output terminals 72p and 72n; and power lines 21 and 22 that connect the pair of secondary-side input/output terminals 72p and 72n and a load 4. The first power line 21 is provided with a first switch unit 31 and a third power line 23 that connects both ends of the first switch unit 31, and the third power line 23 is provided with a third switch unit 33, a DC power supply 30, and a second switch unit 32 in series. The fourth power line 24 connects the third power line 23 and the second power line 22. The fourth power line 24 is provided with a fourth diode 34a that allows an output current of the DC power supply 30.

A power supply system 1 includes: a DC power supply 30; a variable voltage power supply 7 serving as an isolated bidirectional DC/DC converter that outputs power of a variable voltage E2 from a pair of secondary-side input/output terminals 72p and 72n; a positive electrode power line 21 and a negative electrode power line 22 that are connected to both electrodes of the DC power supply 30; a switching circuit 5 including a plurality of arm switching elements 51, 52, 53, and 54 that connect the power lines 21 and 22 and a load 4; a backflow prevention switching element 34 that is provided on the positive electrode power line 21 between the pair of secondary-side input/output terminals 72p and 72n; a power supply driver 6 that operates the variable voltage power supply 7 and the backflow prevention switching element 34; and a switching circuit driver 8.

A power supply system 1 includes: a variable voltage power supply 7 that outputs power of a variable voltage E1 from a pair of secondary-side input/output terminals 72p and 72n; a first power line 21 and a second power line 22 that connect the pair of secondary-side input/output terminals 72p and 72n and a load 4; a first switch unit 31 that is provided on the first power line 21; a third power line 23 that connects both ends of the first switch unit 31; and a bypass line 25 that connects the pair of secondary-side input/output terminals 72p and 72n, a first DC power supply 33 is provided on the third power line 23 to output DC power, and a bypass diode 33a is provided on the bypass line 25 to allow an output current of the first DC power supply 38.