The present invention relates to a resonant DC-DC power converter assembly comprising a first resonant DC-DC power converter and a second resonant DC-DC power converter having identical circuit topologies. A first inductor of the first resonant DC-DC power converter and a second inductor of the second resonant DC-DC power converter are configured for magnetically coupling the first and second resonant DC-DC power converters to each other to forcing substantially 180 degrees phase shift, or forcing substantially 0 degree phase shift, between corresponding resonant voltage waveforms of the first and second resonant DC-DC power converters. The first and second inductors are corresponding components of the first and second resonant DC-DC power converters.

A segmented driver including at least one drive pin and a sense pin, a driver circuit, a comparator, and a controller. The driver circuit activates a selected drive level between the drive pins and a reference node. The comparator compares a voltage of the sense pin with a threshold voltage and provides a threshold indication when the voltage of the sense pin reaches the threshold voltage. The controller commands the driver circuit to activate a first drive level in response to an off indication, and commands the driver circuit to switch to a second, lower drive level in response to the threshold indication. The driver circuit may be implemented using low resistive current devices. Multiple drive pins may be included, each for selectively activating a corresponding drive path to adjust drive level. The threshold voltage may be set using a current source and resistor, and may be adjusted for temperature.

A method for controlling a polyphase inverter that includes a number of half bridges connected into an intermediate voltage circuit and center taps between switching elements. By cyclically switching the switching elements, the respective center taps of the half bridges are connected to an upper intermediate circuit rail or to a lower intermediate circuit rail of the intermediate voltage circuit according to the principle of pulse width modulation. The switching elements of at least one half bridge are driven in a modified manner, at least in some time intervals, in that the switching pulses of at least two consecutive periods of the pulse width modulation are concatenated directly in time as one switching pulse. In this way, the switching frequencies of the correspondingly driven switching elements and thus the switching losses of the latter can be further reduced.

A method for controlling a polyphase inverter that includes a number of half bridges connected into an intermediate voltage circuit and center taps between switching elements. By cyclically switching the switching elements, the respective center taps of the half bridges are connected to an upper intermediate circuit rail or to a lower intermediate circuit rail of the intermediate voltage circuit according to the principle of pulse width modulation. The switching elements of at least one half bridge are driven in a modified manner, at least in some time intervals, in that the switching pulses of at least two consecutive periods of the pulse width modulation are concatenated directly in time as one switching pulse. In this way, the switching frequencies of the correspondingly driven switching elements and thus the switching losses of the latter can be further reduced.

A bidirectional power converter circuit is controlled via a hysteresis loop such that the bidirectional power converter circuit can compensate in near real time for variations and even changes in transmit and receive coil locations without damaging components of the system. Because the bidirectional power converter is capable of both transmitting and receiving power (at different times), one circuit and board may be used as the main component in multiple wireless power converter designs. The bidirectional power converter circuit is used in a proximity wireless power transmitter and a proximity wireless power receiver, such that the transmitter and receiver may be misaligned in any direction while providing power from the transmitter to the receiver without damaging any circuitry of either the bidirectional power converter transmitter or the bidirectional power converter receiver.

A high-frequency power supply apparatus for supplying high-frequency power to a load the impedance of which greatly fluctuates is provided, wherein a stable high-frequency current is always maintained without having overcurrent or overvoltage generated in a drive circuit thereof. In the high-frequency power supply apparatus, a constant-current conversion circuit is connected between an LCR series resonant circuit and a half-bridge drive circuit, high-frequency current of the LCR series resonant circuit is controlled by the voltage of the half-bridge drive circuit, and a constant-current function is applied to impedance variation of the load. Due to the constant-current conversion circuit, the gate of a MOSFET of the half-bridge drive circuit is driven with a parallel capacitor using a transformer inserted in the LCR series resonant circuit, and the phases of the high-frequency current of the LCR series resonant circuit and the output of the half-bridge drive circuit are maintained to be constant.

An inverter circuit comprises: a primary-side circuit including a plurality of self-excited oscillator circuits connected to a DC power supply; and a secondary-side circuit for outputting the multi-phase AC powers in accordance with the oscillations of the self-excited oscillator circuits. Each of the self-excited oscillator circuits includes power transmission coils, a resonant capacitor, a pair of switching elements, a drive coil, and a phase-shift filter. The respective control electrodes of the pair of switching elements are applied with voltages from the drive coil of another one of the self-excited oscillator circuits. The phase of the voltage applied to each of the electrodes of the pair of switching elements is shifted in association with the action of at least the phase-shift filter, with respect to each of the self-excited oscillator circuits, by a phase-shift amount according to the number of phases of output power.