Abstract: Methods and circuits for regulating the voltage of the isolated output of an isolated buck converter. Pursuant to a representative method, a parameter of the primary side of an isolated buck transformer is measured, wherein the parameter is dependent in part upon the output voltage on the secondary side of the transformer. The duty cycle of the isolated buck converter is set based at least in part on the value of the measured parameter.

Abstract: One heuristic for tuning a wireless power transfer device includes monitoring a circuit parameter while sweeping a power source frequency; identifying two frequencies related to local maxima of the circuit parameter values; estimating self-resonant frequency of an electromagnetically coupled device based on the two frequencies; determining a value for a tuning component of the wireless power transfer device such that the device self-resonant frequency equals the estimated coupled device self-resonant frequency; and adjusting the tuning component to the determined value.

Abstract: Methods and circuits for regulating the voltage of the isolated output of an isolated buck converter. Pursuant to a representative method, a parameter of the primary side of an isolated buck transformer is measured, wherein the parameter is dependent in part upon the output voltage on the secondary side of the transformer. The duty cycle of the isolated buck converter is set based at least in part on the value of the measured parameter.

Abstract: A buck-boost converter with smooth transitions is disclosed. A buck-boost converter controller is disclosed including a first high side driver switch gate control signal output for controlling a first high side driver device; a first low side driver switch gate control signal output for controlling a first low side driver device; a second high side driver switch gate control signal output for controlling a second high side driver device; a second low side driver switch gate control signal output for controlling a second low side driver device; a state machine having four states comprising a buck state, a boost state, a transition buck state, and a transition boost state; a hysteresis timer indicating a pulse width greater than a predetermined threshold coupled to the state machine; and a minimum timer indicating a pulse width less than a predetermined threshold coupled to the state machine. Methods are also disclosed.

Abstract: One heuristic for tuning a wireless power transfer device includes monitoring a circuit parameter while sweeping a power source frequency; identifying two frequencies related to local maxima of the circuit parameter values; estimating self-resonant frequency of an electromagnetically coupled device based on the two frequencies; determining a value for a tuning component of the wireless power transfer device such that the device self-resonant frequency equals the estimated coupled device self-resonant frequency; and adjusting the tuning component to the determined value.

Abstract: One heuristic for tuning a wireless power transfer device includes monitoring a circuit parameter while sweeping a power source frequency; identifying two frequencies related to local maxima of the circuit parameter values; estimating self-resonant frequency of an electromagnetically coupled device based on the two frequencies; determining a value for a tuning component of the wireless power transfer device such that the device self-resonant frequency equals the estimated coupled device self-resonant frequency; and adjusting the tuning component to the determined value.

Abstract: A buck-boost converter with smooth transitions is disclosed. A buck-boost converter controller is disclosed including a first high side driver switch gate control signal output for controlling a first high side driver device; a first low side driver switch gate control signal output for controlling a first low side driver device; a second high side driver switch gate control signal output for controlling a second high side driver device; a second low side driver switch gate control signal output for controlling a second low side driver device; a state machine having four states comprising a buck state, a boost state, a transition buck state, and a transition boost state; a hysteresis timer indicating a pulse width greater than a predetermined threshold coupled to the state machine; and a minimum timer indicating a pulse width less than a predetermined threshold coupled to the state machine. Methods are also disclosed.

Abstract: An electrically tunable inductor with an equivalent inductance includes a main winding and a tuning winding magnetically coupled to the main winding. The current through the tuning winding is controlled to adjust the equivalent inductance of the electrically tunable inductor. A device may include an electrically tunable inductor. A system may include multiple devices, one or more of the devices including an electrically tunable inductor. A tuning controller within the system may control the current in tuning windings of one or more of the multiple devices in the system. When an electrically tunable inductor is part of a resonant circuit, the resonant frequency may be controlled by adjusting the equivalent inductance of the electrically tunable inductor through controlling the current in the tuning winding. Controlling the current in the tuning winding includes one or more of controlling the peak, direction, frequency, duty cycle, or phase of the current.

Abstract: One heuristic for tuning a wireless power transfer device includes monitoring a circuit parameter while sweeping a power source frequency; identifying two frequencies related to local maxima of the circuit parameter values; estimating self-resonant frequency of an electromagnetically coupled device based on the two frequencies; determining a value for a tuning component of the wireless power transfer device such that the device self-resonant frequency equals the estimated coupled device self-resonant frequency; and adjusting the tuning component to the determined value.

Abstract: In a wireless energy transfer system, an apparatus includes a coil and an adjustable alternating current power supply electrically connected to the coil. When a device is in the vicinity of the apparatus, the apparatus determines an operating parameter of the device and adjusts a power supply operating parameter based on the determined device operating parameter. The apparatus may be a transmitter wirelessly transmitting power to the device or a receiver wirelessly receiving power from the device. The operating parameter may be frequency, and the apparatus adjusts the power supply frequency to be substantially equal to the device frequency, which may be the device resonant frequency. The operating parameter may be phase, and the apparatus adjusts the power supply phase to be out of phase with the device. The phase of the power supply may be adjusted to ninety degrees out of phase with the device for maximum power transfer.

Abstract: An electrically tunable inductor with an equivalent inductance includes a main winding and a tuning winding magnetically coupled to the main winding. The current through the tuning winding is controlled to adjust the equivalent inductance of the electrically tunable inductor. A device may include an electrically tunable inductor. A system may include multiple devices, one or more of the devices including an electrically tunable inductor. A tuning controller within the system may control the current in tuning windings of one or more of the multiple devices in the system. When an electrically tunable inductor is part of a resonant circuit, the resonant frequency may be controlled by adjusting the equivalent inductance of the electrically tunable inductor through controlling the current in the tuning winding. Controlling the current in the tuning winding includes one or more of controlling the peak, direction, frequency, duty cycle, or phase of the current.