A voltage control apparatus includes a boost converter configured to convert an input voltage to a voltage equal to or higher than a first voltage in an operative state and directly output the input voltage in an inoperative state, a buck-boost converter coupled with the boost converter in parallel and configured to convert the input voltage to a second voltage lower than the first voltage, a memory, and a processor coupled to the memory and configured to keep the buck-boost converter in the operative state, set the boost converter to the inoperative state when the input voltage is equal to or higher than the first voltage, and change the boost converter to the operative state when the input voltage is lower than the first voltage.

An IPT system for wireless power transfer is provided, in particular an IPT system capable of operating at high frequencies. In one aspect there is provided an IPT transmitter comprising a push-pull resonant converter having a resonant frequency and configured to operate at a switching frequency below the resonant frequency and dependent on a switching characteristic of a second converter configured to inductively couple to said transmitter.

A voltage converter circuit includes a high side transistor, a high side driver coupled to a control input of the high side transistor, a low side transistor coupled to the high side transistor at a switch node, and a current steering circuit coupled to the control input of the high side and to the switch node. During transition of the high side transistor to an on state, a current from the high side driver initially divides between the control input of the high side transistor and the current steering circuit, and as a voltage on the switch node increases, less of the current from the high side driver flows through the current steering circuit and more of the current from the high side driver flows to the control input of the high side transistor.

An inductive power transfer circuit or inductive rotary joint has an inductive rotating coupler with a primary side and a primary winding rotatably arranged against a secondary side and a secondary winding. The secondary side is connected via a rectifier to a load. The stray inductance of the coupler together with a resonance capacitor a series resonance circuit having a series resonance frequency. An inverter in a full bridge circuit is provided for converting a DC input voltage into an AC voltage. The inverter is operable in a full bridge mode to deliver a high power level and in a half bridge mode to deliver a low power level. This results in a broad dynamic range, soft power on and improved safety, as switching between the modes may be controlled by a simple hardware.

The invention relates to a method for modulating the boost converter operating mode of a push-pull converter having a low-voltage-side circuit, having a first low-voltage-side switching device and a second low-voltage-side switching device; having a transformer having a high-voltage-side winding; and having a high-voltage-side circuit, which is configured as a full-bridge rectifier, having a first and a second rectification element which form a first half-bridge and a third and a fourth rectification element which form a second half-bridge; wherein the method comprises the steps of closing the first low-voltage-side switching device while simultaneously short-circuiting the high-voltage-side winding via the first or the fourth rectification element during a first time segment; opening the rectification element used for short-circuiting the high-voltage-side winding during a second time segment; opening the first low-voltage-side switching device and closing the second low-voltage-side switching device while simultaneously short-circuiting the high-voltage-side winding via the third or the fourth rectification element in the second half-bridge during a third time segment; and opening the rectification element used for short-circuiting the high-voltage-side winding during a fourth time segment.

A cooling structure for a heat-producing power magnetics device having at least two faces, includes a first cold plate having a first coolant passage and conductively coupled with at least the first face of the magnetics device and wherein at least a portion of heat generated by the power magnetics device is removed from the device by way of thermal conduction to the first coolant passage, and a coolant reservoir fluidly coupled with the first and second coolant passages.

A control circuit operable to generate a control signal to control the duty cycle of a switched mode power supply is provided. The control circuit comprises an input terminal for receiving a signal indicative of an input voltage (V.sub.in) of the switched mode power supply, and a reference signal generator to generate, in dependence upon the received signal, a reference signal (V.sub.R) that is a function of the input voltage (V.sub.in). The control circuit further comprises an error signal generator to receive a signal indicative of an output voltage (V.sub.out) of the switched mode power supply and to generate an error signal (V.sub.E) based on the reference signal (V.sub.R) and based on the output voltage, a low pass filter, and a duty cycle control signal generator to generate the control signal to control the duty cycle of the switched mode power supply in dependence upon the error signal (V.sub.E).

A driver circuit for synchronous rectifier electronic switches, such as SR MOSFETs in resonant converters controls a pair of synchronous rectifier electronic switches to apply thereto a drive voltage to switch the synchronous rectifier electronic switches on and off synchronously with a converter current. The driver circuit includes a programming module to produce a first signal indicative of the figure of merit of the synchronous rectifier electronic switches, and, optionally, a current sensing module to produce a second signal indicative of the output current of the synchronous rectifier electronic switches. An output module is included to generate a value for the drive voltage which is a function of the first signal indicative of the figure of merit and, optionally, of the second signal indicative of the output current of the synchronous rectifier electronic switches.

A variable direct current (DC) link power converter is described. In one example, the power converter includes a first converter stage configured to convert power from a power source to power at an intermediate link voltage and a second converter stage configured to convert the power at the intermediate link voltage to power for charging a battery. The power converter further includes a control system having an intermediate link voltage regulation control loop configured, in a first mode of operation, to regulate the intermediate link voltage through the first converter stage based on a voltage of the battery, and a ripple regulation control loop configured to sense a charging current for the battery and regulate a gain of the second converter stage based on the charging current to reduce ripple in the charging current. A new configuration of transformer suitable for use with the power converter is also described.

A double-ended forward converter includes: a first switching element and a second switching element that are coupled to a primary side of a transformer; a pulse generation circuit that generates a pulse signal for controlling the first and second switching elements; an isolation transformer that converts the pulse signal into an alternating-current signal; a rectifier circuit that rectifies the alternating-current signal and generate gate voltages of the first and second switching elements; a driver circuit that includes a third switching element which drives gates of the first and second switching elements, a voltage generated on a secondary side of the isolation transformer being input to a gate of the third switching element; and a minus bias generation circuit that generates a source voltage of the third switching, based on a change in the voltage generated on the secondary side of the isolation transformer.