Controllers and methods for controlling a resonant power converter output voltage include operating the power converter according to a control period comprising an on cycle operation mode for a duration T_on that produces a first voltage Vo1 and an off cycle operation mode for a duration T_off that produces a second voltage Vo2. Vo1 is produced using a first switching frequency for a first selected number of switching cycles corresponding to the on time T_on. The converter output voltage or the converter input and output voltages may be sensed and used to determine the switching frequency during the on cycle operation mode and the duration of the off cycle operation mode. The final output voltage of the power converter is regulated to a selected value based on a ration of (T_on):(T_on+T_off). The controllers and methods may be used with power converters in power delivery devices to accept wide input voltage ranges compatible with devices such as cell phones, tablet computers, and notebook computers.

A contactless power supply device that supplies electric power to a vehicle in a contactless manner, includes: a power transmission resonance circuit; a power source circuit supplying direct-current power; and a power transmission circuit converting the direct-current power of the power source circuit into alternating-current power and supplying alternating-current power to the power transmission resonance circuit. The power transmission circuit includes: an inverter circuit converting the direct-current power of the power source circuit into alternating-current power; and a power transmission-side immittance conversion circuit adjusting the alternating-current power of the inverter circuit and supplies the adjusted alternating-current power to the power transmission resonance circuit. The ratio of a characteristic impedance of the power transmission-side immittance conversion circuit to an impedance backward on the power transmission resonance circuit side from the power transmission-side immittance conversion circuit is adjusted such that harmonic components in the alternating-current power of the inverter circuit becomes lessened.

The switching power supply is provided with a voltage converter including a switching element for inputting a voltage from an input terminal, and has a spread spectrum function of varying a switching frequency in the switching element within a predetermined variation range. The switching power supply has a frequency setting unit that sets the variation range of the switching frequency and raises a lower limit value of the set variation range when a value of the voltage input from the input terminal is equal to or more than a predetermined threshold, and a signal generator that generates a control signal for driving the switching element by varying the switching frequency within the variation range set by the frequency setting unit.

A wireless power receiver circuit and method for use in a wireless power transfer system are provided for providing a constant current and voltage to an electrical load, such as a chemical cell device. A wireless power receiver circuit include a first comparator circuit and a second comparator circuit configured to receive output signals output from the DC load circuit, compare the received output signal with a preselected reference voltage signal, and output first and second sub-control signals, respectively. A logical gate may generate a control signal based on a comparison of the first sub-control signal and the second sub-control signal, and feed the control signal back to a resonator circuit to control a state of an electrically-controllable switch.

Disclosed herein are tunable reactance circuits configured to present a tunable or variable capacitive reactance when energized. The circuits can include a switch configured to be controlled by a gate driver, the gate driver configured to receive a control signal indicating an on-time of the switch; a diode coupled antiparallel to a switch; and one or more capacitors coupled in parallel to the diode. The tunable capacitive reactance can be based on the on-time of the switch and a total capacitance value of the one or more capacitors. The exemplary tunable reactance circuits may be used in wireless power transmitters and/or receivers for efficient power transmission and/or to deliver a particular level of power to a load.

A power conversion device is equipped with at least one leg circuit containing two switching elements connected in series, respectively, a transformer having a primary winding and a secondary winding, a capacitor connected between the leg circuit and one end of the primary winding, a switch circuit, and a rectifier circuit. The switch circuit selectively connects one of a plurality of winding sections of the secondary winding that are different from each other to the rectifier circuit

A power converter circuit includes an input configured to receive an input voltage and an output configured to provide an output voltage; a main converter coupled between a main converter input and the output and comprising a first winding and a second winding that are inductively coupled; and an auxiliary converter comprising an auxiliary converter input coupled to a third winding and an auxiliary converter output, wherein the third winding is inductively coupled with the first winding and the second winding. The auxiliary converter output is coupled between the input and the main converter input.

A power converter apparatus is provided with: a plurality of leg circuits, each including two switch circuits connected in series between input terminals; a transformer including a primary winding and a secondary winding, the primary winding having a first terminal and a second terminal; and at least one capacitor. The at least one capacitor is connected between the first terminal or the second terminal of the primary winding of the transformer, and a node between the two switch circuits in at least one leg circuit among the plurality of leg circuits. The first terminal of the primary winding of the transformer is connected to at least two nodes between the switch circuits in at least two first leg circuits among the plurality of leg circuits, via at least two first circuit portions having at least one of capacitances and inductances different from each other, respectively.

A power converter apparatus is provided to include a switching circuit, and a filter circuit. The switching circuit generates an AC voltage by switching a DC voltage at a predetermining switching frequency, and the filter circuit converts the AC voltage from the switching circuit into the DC voltage by low-pass filtering the AC voltage. The filter circuit induces first and second bypass capacitors, and an inductor. The first bypass capacitor bypasses noise of a first frequency component of the AC voltage from the switching circuit, and the second bypass capacitor bypasses noise of a second frequency component of the AC voltage from the switching circuit, which is lower than the first frequency component. The inductor is inserted between the first and second bypass capacitors, and the inductance thereof is set so that a resonance frequency of the filter circuit is lower than the switching frequency by insertion of the inductor.

A resonant tank converter including a reconfigurable resonant tank circuit including a switch configured to switch a resonant tank configuration of the reconfigurable resonant tank circuit to a first or second configuration in response to feedback signals representative of the output to a load. In some embodiments, the first configuration is an LLC resonant tank configuration, and the second configuration is an LCC resonant tank configuration.