Abstract: A wireless transmitter coordinates changes in the transmitter's input or output voltages with changes in the transmitter's operating frequency to counteract the transmitter's output power changes while changing the voltages. When the voltages are being increased, the output frequency is moved away from the resonant frequency. Consequently, the output power increase due to the increased voltages is restrained by the frequency change. Before or after the voltage increase, increased output power can be obtained by changing the output frequency while the input and output voltages are held constant or near constant. Some embodiments follow similar procedures when reducing the transmitter's input or output voltages. Calibration is performed before power transfer to determine suitable voltage and frequency profiles for voltage change operations. Other features are also provided.

Abstract: A wireless power device is presented that avoids transmit conflicts. The device can include a rectifier circuit coupled to a coil; a transmit driver coupled to the rectifier circuit; a transmit detect circuit configured to detect receipt of transmitted wireless power at the coil; and a controller coupled to the transmit driver and the transmit detect circuit, the controller receiving a signal from the transmit detect circuit and providing an alert of the presence of the transmitted wireless power, the controller activating the transmit driver to transmit wireless power in absence of the signal. The wireless device can determine an operating mode and in a transmit mode determine presence of a received power. If received power is detected an alert can be provided and an off state initiated. If transmit power is not detected the transmit driver can be activated.

Abstract: A Universal Serial Bus (USB)-Power Delivery (PD) integrated circuit (IC) controller is described. The controller includes: a first USB port configured for coupling the USB-PD IC controller to a USB power adaptor; a second port configured for coupling the USB-PD IC controller to a wireless charging station; and logic configured to control a level of a voltage output by the USB power adaptor and to control an output power level of the wireless charging station, wherein an input voltage of the wireless charging station corresponds to the voltage output by the USB power adaptor or is derived from the voltage output by the USB power adaptor. The IC controls both USB-PD and wireless power simultaneously as a system to transmit power and may limit the output power to prevent overload conditions. A corresponding wireless charging system and method of operating the wireless charging system are also described.

Abstract: A wireless power transmitter pulses the transmit power level unresponsively to the wireless power receiver's power requests in order to perform foreign object detection (FOD). The FOD is performed by the transmitter analyzing the receiver's responses to the pulsed power. Some embodiments avoid mistaking FOD for coil misalignment. Other features are also provided.

Abstract: A gate driver circuit for a synchronous rectifier (SR) of a wireless power receiver (WPR) system includes: a first RC filter that outputs a delayed turn-on signal for a first high-side SR switch based on a signal input to the filter that indicates a zero-crossing condition for a coil current of the WPR system in a first direction; a second RC filter that outputs a delayed turn-on signal for a second high-side SR switch based on a signal input to the filter that indicates a zero-crossing condition for the coil current in the opposite direction; a first digital delay-and-hold circuit electrically connected to the output of the first RC filter and that stabilizes the delayed turn-on signal output by the first filter; and a second digital delay-and-hold circuit electrically connected to the output of the second RC filter and that stabilizes the delayed turn-on signal output by the second filter.

Abstract: According to some embodiments, a wireless power transmitter is disclosed. The wireless power transmitter can include a plurality of transmission coils arranged to cover a charging area and coupled with a ferrite; a plurality of local power controllers, each of the plurality of local power controllers coupled to drive a subset of the plurality of transmission coils, each subset of the plurality of transmission coils including a plurality of the plurality of transmission coils; and a microcontroller unit (MCU) coupled to the plurality of local power controllers, the microcontroller unit including a MCU processor executing instructions to designate states of each of the plurality of transmission coils, the states including active, de-active, and selected for receiver detection, and executing instructions to transmit instructions to each of the plurality of local power controllers in accordance with the state designations.

Abstract: A system and method of transmitting power according to some embodiments includes sequentially pinging each of a plurality of transmit coils to locate a receiver; determining one or more active coils from the plurality of transmit coils based on the location of the receiver; activating the one or more active coils in a full-bridge mode to transfer power to the receiver; determining a base efficiency based on the one or more active coils; monitoring non-active ones of the plurality of transmit coils; determining if the receiver has moved based on the monitoring; if the receiver has moved to a new position, determining secondary coils according to the new position, and transitioning power to provide power from a new active coil configuration.

Abstract: In accordance with some embodiments of the present invention, a wireless power receiver that ramps an ASK impedance is presented. A method of amplitude shift key (ASK) modulation in a wireless power receiver includes initiating transition of an ASK impedance from a first state to a second state, the ASK impedance being coupled to a resonant circuit that includes a wireless power receive coil that receives a time-varying magnetic field; transitioning the ASK impedance from the first state to the second state according to the transition over a plurality of switching cycles of the time-varying magnetic field; and holding the second state.

Abstract: A wireless power transmitter pulses the transmit power level unresponsively to the wireless power receiver's power requests in order to perform foreign object detection (FOD). The FOD is performed by the transmitter analyzing the receiver's responses to the pulsed power. Some embodiments avoid mistaking FOD for coil misalignment. Other features are also provided.

Abstract: In accordance with some embodiments of the present invention, a wireless power receiver that ramps an ASK impedance is presented. A method of amplitude shift key (ASK) modulation in a wireless power receiver includes initiating transition of an ASK impedance from a first state to a second state, the ASK impedance being coupled to a resonant circuit that includes a wireless power receive coil that receives a time-varying magnetic field; transitioning the ASK impedance from the first state to the second state according to the transition over a plurality of switching cycles of the time-varying magnetic field; and holding the second state.

Abstract: A wireless transmitter coordinates changes in the transmitter's input or output voltages with changes in the transmitter's operating frequency to counteract the transmitter's output power changes while changing the voltages. When the voltages are being increased, the output frequency is moved away from the resonant frequency. Consequently, the output power increase due to the increased voltages is restrained by the frequency change. Before or after the voltage increase, increased output power can be obtained by changing the output frequency while the input and output voltages are held constant or near constant. Some embodiments follow similar procedures when reducing the transmitter's input or output voltages. Calibration is performed before power transfer to determine suitable voltage and frequency profiles for voltage change operations. Other features are also provided.

Abstract: According to some embodiments, a wireless power transmitter is disclosed. The wireless power transmitter can include a plurality of transmission coils arranged to cover a charging area and coupled with a ferrite; a plurality of local power controllers, each of the plurality of local power controllers coupled to drive a subset of the plurality of transmission coils, each subset of the plurality of transmission coils including a plurality of the plurality of transmission coils; and a microcontroller unit (MCU) coupled to the plurality of local power controllers, the microcontroller unit including a MCU processor executing instructions to designate states of each of the plurality of transmission coils, the states including active, de-active, and selected for receiver detection, and executing instructions to transmit instructions to each of the plurality of local power controllers in accordance with the state designations.

Abstract: A system and method of transmitting power according to some embodiments includes sequentially pinging each of a plurality of transmit coils to locate a receiver; determining one or more active coils from the plurality of transmit coils based on the location of the receiver; activating the one or more active coils in a full-bridge mode to transfer power to the receiver; determining a base efficiency based on the one or more active coils; monitoring non-active ones of the plurality of transmit coils; determining if the receiver has moved based on the monitoring; if the receiver has moved to a new position, determining secondary coils according to the new position, and transitioning power to provide power from a new active coil configuration.

Abstract: Embodiments herein provide a device for calibrating a voltage driven by a PWM signal for a circuit board. The device includes a controller configured to generate the PWM signal according to a PWM duty cycle value, and a voltage regulator configured to generate an output voltage according to the PWM signal. The controller is further configured to calibrate a relationship between the PWM duty cycle value and the output voltage based on a plurality of configured PWM duty cycle values and a plurality of corresponding voltages measured from the voltage regulator, and drive the circuit board by configuring the PWM duty cycle value based on the calibrated relationship.

Abstract: A wireless power device is presented that avoids transmit conflicts. The device can include a rectifier circuit coupled to a coil; a transmit driver coupled to the rectifier circuit; a transmit detect circuit configured to detect receipt of transmitted wireless power at the coil; and a controller coupled to the transmit driver and the transmit detect circuit, the controller receiving a signal from the transmit detect circuit and providing an alert of the presence of the transmitted wireless power, the controller activating the transmit driver to transmit wireless power in absence of the signal. The wireless device can determine an operating mode and in a transmit mode determine presence of a received power. If received power is detected an alert can be provided and an off state initiated. If transmit power is not detected the transmit driver can be activated.

Abstract: Embodiments described herein provide a wireless power transmitter that dynamically adjusts the deadtime to reduce power loss. Specifically, the wireless power transmitter includes a transistor circuit for switching a first voltage at a first node and a second voltage at a second node, and a LC circuit coupled between the first node and the second node. The wireless power transmitter further includes a controller coupled to the transistor circuit. The controller is configured to determine whether either of the first voltage and the second voltage is negative during a deadtime of switching. The controller is configured to increment or decrement the deadtime by an adjustment amount depending on whether negative voltage is detected.

Abstract: In a wireless power transfer operation, the operating parameters are adjusted to improve efficiency by reducing the transmit and receive coil currents as follows. First, the transmitter causes the receiver to reduce the receive coil current to the lowest value based on the transmitter/receiver communication while still delivering the same amount of power to the load as before the AC current was adjusted to the minimum value. Then the transmitter may change the operating parameters to increase or preserve the power provided to the receiver without decreasing efficiency or with only small decrease in efficiency, or with increasing the efficiency. For example, the transmitter may increase the VBRG voltage (the DC voltage powering the transmit coil) or the operating frequency to maintain or increase output power levels at lower or the same AC and DC current levels. Other features are also provided.

Abstract: A capacitor sensor array (or grid) over a wireless power transmission coil can include a first set of lines; a second set of lines intersecting the first set of lines; a first multiplexer coupled to provide a charge (e.g. in the form of a DC voltage) from a voltage source to the first set of lines and provide first signals to detect voltages on each line; and a second multiplexer coupled to provide a charge from the voltage source to the second set of lines and provide second signals to detect voltages on each line, wherein an object positioned with respect to the first set of lines and the second set of lines is located. According to some embodiments, a wireless power receive coil and a rectifier circuit can be used in forming a capacitor sensor, to sense the capacitance between the receive and transmit coils for better alignment between the two coils. Other embodiments are also provided.

Abstract: In accordance with some embodiments of the present invention, a method of determining a Q-factor in a transmit circuit with a resonant circuit includes setting a system voltage; performing a coarse scan to determine a course resonant frequency; performing a fine scan based on the course scan to determine a resonant frequency; performing a final measurement at the resonant frequency to determine an average system voltage and an average peak voltage of the resonant circuit; calculating a Q parameter from the average system voltage and the average peak voltage; and calculating the Q-factor from the Q parameter.

Abstract: A capacitor sensor array (or grid) over a wireless power transmission coil can include a first set of lines; a second set of lines intersecting the first set of lines; a first multiplexer coupled to provide a charge (e.g. in the form of a DC voltage) from a voltage source to the first set of lines and provide first signals to detect voltages on each line; and a second multiplexer coupled to provide a charge from the voltage source to the second set of lines and provide second signals to detect voltages on each line, wherein an object positioned with respect to the first set of lines and the second set of lines is located. According to some embodiments, a wireless power receive coil and a rectifier circuit can be used in forming a capacitor sensor, to sense the capacitance between the receive and transmit coils for better alignment between the two coils. Other embodiments are also provided.