Nxp Usa, Inc.

Huan Mao

Dechang Wang

Dengyu Jiang

Li Wang

Yong Wang

Xiang Gao

Radek Holis

Wei Cao

Ruyang Sheng

Power transmission associated with wireless charging of a battery of an electronic device or powering of the electronic device comprises determining a power loss associated with transmitting a power signal having a transmitted power from the wireless power transmitter to a wireless power receiver. A closed loop power loss control based on the power loss is performed which comprises outputting a target transmit power to meet a power loss limit. The power signal having the target transmit power is wirelessly transmitted to the wireless power receiver to charge the battery of the electronic device or power the electronic device and balance charging performance and safety.

Closed loop power loss control of wireless power transmission, and methods for wireless power transmission

A method for determining a quality factor of a wireless charger is disclosed. The wireless charger includes an inverter, a filter, and a resonant tank circuit. The inverter receives a supply voltage and generates a PWM signal at a first node and a second node. The filter connects to the first and second nodes of the inverter to receive the PWM signal, and generates a filtered signal at a first terminal and a second terminal of a capacitor. The resonant tank circuit connects to the first and second terminals of the capacitor of the filter to receive the filtered signal, and provides wireless power at an inductor coil to a receiver. The method includes: issuing a current pulse to the resonant tank circuit; and in a Q-factor determination phase of the wireless charger, connecting the resonant tank circuit and only the capacitor of the filter in a resonance network.

Method for determining a quality factor and wireless charger

A wireless power transmitter to wirelessly transmit power applies a current or voltage to a transmitter coil based on an indication of coupling being in a predetermined range. The current or voltage which is applied causes the transmitter coil to transmit a high power (HP) DPING. A response to the HP DPING indicates that a wireless power receiver is located on a charging surface and a power signal is then transmitted to the wireless power receiver to charge or power an electronic device coupled to the wireless power receiver. Use of HP DPING improves the wireless power transmission performance including transmission area and interoperability of wireless power transmitters with low coupling to wireless power receivers.

Wireless power transmitter which detects low coupling with a wireless power receiver, and methods for wireless power transmission

A method of compensating for temperature dependent Q factor variations in a wireless charger includes receiving, by the wireless charger, a reference Q factor value from a device to be charged. The method also includes the wireless charger determining a Q factor threshold value from the reference Q factor. The method further includes the wireless charger measuring a Q factor associated with a transmit coil of the wireless charger. The method also includes determining a temperature value. The method further includes applying a temperature compensation calculation to the measured Q factor using the temperature value to produce a temperature compensated Q factor. The method also includes comparing the temperature compensated Q factor with the Q factor threshold value. The method may also include compensation for temperature dependent internal power loss values.

Wireless charging method, device and system

Apparatus and methods of providing digital varying output, such as sinusoidal, pulse width modulation, SPWM, control for an inverter comprising at least a first switch and a second switch are disclosed. The method comprising: generating a first binary control signal at a system modulation frequency; generating a second binary control signal at an M-times higher carrier frequency; wherein generating the second binary control signal comprises: providing a periodic counter having a K-times higher reset frequency; calculating M switch-off moments; determining for each, a corresponding switch-off counter value and a corresponding counter sequence value; storing each switch-off counter value in a respective memory location corresponding to the respective counter sequence and dummy values in the remaining memory locations; and sequentially and periodically transferring the contents of the memory locations to at least one PWM value register.

Apparatus and methods for varying output pulse-width modulation (PWM) control of an inverter

A wireless charger includes a rectifier, a first filter that includes an inductor, a resonant tank circuit, and a second filter that includes a switch. The rectifier receives a drive signal from a voltage supply and generates a rectified voltage signal. The rectified voltage signal is filtered by the first filter and the filtered signal is provided to the tank circuit, which resonates to provide power wirelessly to a receiver. The switch of the second filter is connected in parallel with the inductor of the first filter. The switch is closed in order to bypass the inductor during a detection phase in which the wireless charger determines a quality factor of the tank circuit.

Q-factor determination in wireless charging system having complex resonant circuit

A wireless charger includes multiple transmitter coils, first and second drivers, and a controller. The transmitter coils are arranged close to and/or overlap with each other. The first driver is coupled with at least one of the transmitter coils to drive the transmitter coil to communicate with and/or provide power over a first channel to receiver devices. The second driver is coupled with at least another one of the transmitter coils to drive the transmitter coil to communicate with and/or provide power over a second channel to receiver devices. The controller is coupled with the first and second drivers and enables only one of the first and second drivers at a time during a first stage.

Multi-coil wireless charger

A wireless charging system (transmitter) has multiple transmit coils that allows for multiple receiver devices (receivers), such as cell phones, to be charged simultaneously. The receivers send data packets that include a receiver ID to the transmitter so that one of the transmitter coils can be paired with a respective one of the receivers. The transmitter can then distinguish between the communications with the receivers using the IDs such that communications with receivers connected with adjacent ones of the transmitter coils do not interfere with each other.

Method of pairing receiver with wireless charger transmitter

A power converter having a switch network, a resonant tank network, and a controller performs in situ determination of the Q-factor of the resonant tank network. The controller excites transitory damped oscillations of the resonant tank network by applying a limited number of ON-pulses to the transistor switches of the switch network. The controller then samples the envelope of the waveform corresponding to the excited transitory damped oscillations and processes the resulting set of digital signal samples to determine the Q-factor of the resonant tank network. The Q-factor determination can be repeated to prevent the power converter from being operated under undesirable operating conditions caused by certain ambient factors, such as the unexpected presence of metal objects in the immediate vicinity of the power converter.

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Suzhou, China

Huan Mao