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.

Disclosed herein is an improved flyback converter that separates the magnetic components of the converter into a transformer and a separate, discrete energy storage inductor. This arrangement can improve the operating efficiency of the converter by reducing the commutation losses as compared to a conventional flyback converter. The magnetic components may be constructed on separate magnetic cores or may be constructed on magnetic cores having at least one common element, thereby allowing for at least partial magnetic flux cancellation in a portion of the core, reducing core losses.

The present disclosure discloses a current detecting circuit of a power converter, which includes a transformer including: a magnetic core, a primary winding and a secondary winding, the primary winding and the secondary winding being coupled through the magnetic core, and a combination of the primary winding, the secondary winding and the magnetic core being used to transmit a main power of the power converter, the current detecting circuit includes: an auxiliary winding coupled to the secondary winding, the auxiliary winding and the secondary winding having the same number of turns and their dotted terminals being connected; and an impeder, one end thereof being coupled to the auxiliary winding to form a series branch, which is coupled in parallel to the secondary winding, and a terminal voltage of the impeder after being filtered being proportional to a magnitude of an output current of the power converter.

A control unit is provided. The control unit is configured to provide a control signal for controlling a power unit. The power unit includes a first positive voltage terminal, a second positive voltage terminal, a first negative voltage terminal, a second negative voltage terminal, and a switching element. The first negative voltage terminal and the second positive voltage terminal are coupled to each other in a short circuit manner. One terminal of the switching element is electrically connected to the first negative voltage terminal. The control unit is configured to: receive a pulse width modulation signal; receive a first power supply signal; receive a second positive voltage terminal signal; output a second power supply signal; and output the control signal for controlling the switching element to be turned on or turned off.

A circuit (100) for use in voltage supply for an electrical device, having a first input (111) configured for connecting with a first voltage source, a second input (121) configured for connecting with a second voltage source, and a common output (133) configured for connecting with an input of the electrical device, comprising a first voltage converter (110) with an input connected to or being the first input (111), and configured to provide DC voltage at a first voltage level (V.sub.1) at an output (113), further comprising a second voltage converter (120) with an input connected to or being the second input (121), and configured to provide DC voltage at a second voltage level (V.sub.2) at an output (123), wherein the second voltage converter (120) is configured not to operate when a voltage level present at its output (123) is higher than a stop threshold, and to operate when a voltage level present at its output (123) is lower than a start threshold, the stop threshold is equal to or higher than the second voltage level (V.sub.2) and lower than the first voltage level (V.sub.1), and the start threshold is equal to or lower than the second voltage level (V.sub.2).

A power supply circuit for a switching mode power supply, having: a charging capacitor coupled to an auxiliary winding; a power supply diode coupled to a power supply capacitor, wherein the charging capacitor has a connecting terminal coupled to the power supply diode, and the charging capacitor and the power supply diode are serially coupled between the auxiliary winding of the switching mode power supply and the power supply capacitor; and a power supply switch coupled between the connecting terminal and a primary ground of the switching mode power supply.

A solar charging system for the vehicle includes a first photovoltaic (PV) module, a second PV module serially connected to the first PV module, and a differential power processing (DPP) transformer that converts power generated from the first PV module and the second PV module by using a magnetic body having a multi-winding structure.

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 method involves controlling, for a duration of a first modulation period, a first average off-time of a main switch of a power converter such that the first average off-time of the main switch corresponds to a first intermediate valley number of multiple intermediate valley numbers, an average of the intermediate valley numbers corresponding to a target number of valleys of a resonant waveform at a drain node of the main switch. A second intermediate valley number of the intermediate valley numbers is selected upon expiration of the first modulation period. A difference of the second intermediate valley number and the first intermediate valley number is equal to a fractional valley number offset. A second average off-time of the main switch is controlled for a duration of a second modulation period such that the second average off-time of the main switch corresponds to the second intermediate valley number.

A CCM-based fly-back switching power supply circuit includes: a constant current control circuit, a sampling circuit and a peak current control circuit, wherein a sampling circuit is configured to sample the ON-time of the secondary coil to obtain its duty cycle signal D_SEC, and send the signal to a constant current control circuit; a constant current control circuit is configured to receive the duty cycle signal D_SEC, generate a voltage signal CAC from the duty cycle signal D_SEC and the preset reference voltage signal VREF, convert the voltage signal CAC and the peak current control signal VCST from the peak current control circuit into time signals, and conform a comparison on the time signals to output an adjustment signal CCOUT which is used to initiatively adjust the value of the peak current control signal VCST to cause the fly-back switching power supply circuit output a constant current.