Microchip Technology Inc.

Santosh Bhandarkar

Alex Dumais

A wireless power transmitter and methods to: determine a transmitter frequency bandwidth of the wireless power transmitter when no wireless power receiver is inductively coupled with the wireless power transmitter; determine a transmitter-receiver frequency bandwidth when a wireless power receiver is inductively coupled with the wireless power transmitter; compare the transmitter-receiver frequency bandwidth and the transmitter frequency bandwidth; and detect a foreign object near the transmit coil based on the comparison of the transmitter-receiver frequency bandwidth and the transmitter frequency bandwidth.

Foreign object detection by frequency bandwidth comparison

Foreign object detection and related apparatuses, methods, and systems are disclosed. An apparatus includes one or more inductive coils to wirelessly couple with another inductive coil, a series capacitor electrically connected in series with the one or more inductive coils, and a controller to determine a coil current through the one or more inductive coils responsive to a capacitor voltage potential difference across the series capacitor and determine a coil power responsive to the determined coil current and a coil voltage potential difference across the one or more inductive coils.

Foreign object detection and related apparatuses, methods, and systems

In one or more examples, an apparatus may comprise a wireless power transmitter. The apparatus may include transmitter circuitry including a transmit coil to inductively couple with a receive coil of a wireless power receiver. The apparatus may further include a controller to control the transmitter circuitry to generate a wireless power signal in the transmit coil; perform demodulation on a communication signal, modulated over the wireless power signal, in attempt to decode one or more packets from the wireless power receiver; and perturb an operating point of the transmitter circuitry responsive to identifying a failure in decoding the one or more packets.

Apparatus and method for perturbation of operating point for prevention of wireless power transfer stalling

A foreign object may be detected by measuring inductance and resistance of a transmitter coil using a meter circuit when a plurality of currents are applied to the transmitter coil when the transmitter coil is in standalone conditions and when a receiver coil is mated to the transmitter coil without a foreign object present. A simulation model is generated based on the measured inductance and resistance of the transmitter coil and receiver coil and comprising a characteristic curve as a function of the plurality of currents applied to the transmitter coil. With the receiver coil mated to the transmitter coil, a foreign object may be detected by measuring a power loss from the transmitter coil to the receiver coil based on the simulation model.

Power loss accounting method for in-power foreign object detection

Object detection for wireless power transmitters and related systems, methods, and devices are disclosed. A controller for a wireless power transmitter is configured to receive a measurement voltage potential responsive to a tank circuit signal at a tank circuit, provide an alternating current (AC) signal to each of the plurality of transmit coils one at a time, and determine at least one of a resonant frequency and a quality factor (Q-factor) of the tank circuit responsive to each selected transmit coil of the plurality of transmit coils. The controller is also configured to select a transmit coil to use to transmit wireless power to a receive coil of a wireless power receiver responsive to the determined at least one of the resonant frequency and the Q-factor for each transmit coil of the plurality of transmit coils.

Low power object detection in multi-coil wireless charging systems and related systems, methods, and devices

Foreign object detection for wireless power transmission and related systems, methods, and devices are disclosed. A controller for a wireless power transmitter is to determine a transmit coil voltage potential at a transmit coil of the wireless power transmitter, determine an input power provided to the wireless power transmitter, determine a transmitter power loss, and determine a transmitted power of the wireless power transmitted to the wireless power receiver based, at least in part, on the input power and the transmitter power loss. The controller is also to compute a power loss responsive to the transmitted power and a received power indicated by the wireless power receiver, and determine that a foreign object is detected responsive to a determination that the power loss is greater than a predetermined threshold.

Object detection in wireless charging systems and related systems, methods, and devices

Object detection in wireless power systems and related system, methods, and devices are disclosed. A controller for a wireless power transmitter includes a measurement voltage potential input terminal and a processing core. The processing core is to determine an average of peak to peak amplitude differences present in sampled measurement voltage potentials for each of the plurality of transmit coils, determine a lowest average of the peak to peak amplitude differences, and select a transmit coil corresponding to the lowest average of the peak to peak amplitude differences to transmit wireless power to a receive coil of a wireless power receiver. A wireless power system includes a tank circuit selectively including any one of a plurality of transmit coils.

Transmit coil selection responsive to average peak to peak measurement voltage potentials and related apparatuses and method

Apparatuses and methods related to a converter are disclosed. An apparatus includes a converter and a controller. The converter converts an input voltage potential to an output voltage potential. The input voltage potential and the output voltage potential include direct current (DC) voltage potentials. The controller generates pulse width modulation (PWM) signals responsive to a duty cycle control signal, controls the converter via the PWM signals in a buck mode when the duty cycle control signal is less than a predetermined maximum buck value, and controls the converter via the PWM signals in a cascaded buck-boost mode (CBB mode) when the duty cycle control signal is greater than the predetermined maximum buck value. A duty cycle of at least a portion of the PWM signals transitions linearly with the duty cycle control signal from the buck mode to the CBB mode.

Converters and related apparatuses and methods

Foreign object detection for wireless power transmitters and related apparatuses and methods are disclosed. An apparatus includes an analog-to-digital converter to sample at least one of a coil voltage potential and a coil current representation of a transmit coil inductively coupled to a receive coil of a wireless power receiver with a distance between the transmit coil and the receive coil. The apparatus also includes a processing core to determine an expected reference Q-factor value responsive to the at least one of the sampled coil voltage potential and the sampled coil current representation. The expected reference Q-factor value indicates a Q-factor value expected at a predetermined reference wireless power transmitter inductively coupled to the wireless power receiver with a reference distance from a reference transmit coil of the predetermined reference wireless power transmitter to the receive coil of the wireless power receiver.

Foreign object detection in wireless charging systems and related apparatuses and methods

Various methods relate to digital demodulation for wireless power transmission. A method of operating a wireless power transmitter includes transmitting, with a transmitter coil of a wireless power transmitter, power to a receiver coil of a wireless power receiver. The method also includes sampling one or more electrical signals of the wireless power transmitter. The one or more electrical signals are modulated responsive to alteration of electrical conditions at the wireless power receiver. The method further includes digitally demodulating the sampled one or more electrical signals using a digital filter to obtain a communication from the wireless power receiver. The digital filter includes at least two low pass filter stages that each filter out a fundamental frequency used for the transmission of the power to the receiver coil.

Digital demodulation for wireless power transfer and related methods

Foreign object detection for wireless power transmitters and related systems, methods, and devices are disclosed. A controller for a wireless power transmitter includes a processing core and an analog to digital converter configured to sample at least one of a coil voltage potential and a coil current of a transmit coil. The processing core is configured to determine an expected reference Q-factor value responsive to the at least one of the sampled coil voltage potential and the sampled coil current, and compare the expected reference Q-factor value to a reference Q-factor value received from a wireless power receiver. The processing core is further configured to determine that a foreign object is detected proximate to the transmit coil responsive to a comparison of the expected Q-factor value to the reference Q-factor value received from the wireless power receiver.

Foreign object detection in wireless charging systems and related systems, methods, and devices

Systems, methods, and devices related to a converter of a wireless power transmitter are disclosed. A controller for a wireless power transmitter is configured to sample an output voltage potential to produce a digital output voltage potential, determine an error between an output reference voltage potential and the digital output voltage potential, filter the error to determine a filtered error, and apply an adaptive gain to the filtered error to determine a duty cycle control signal. The adaptive gain is determined responsive to a converter input voltage potential of the converter of the wireless power transmitter. The controller is further configured to determine a controller output including buck pulse width modulation (PWM) signals and boost PWM signals based on the duty cycle control signal, the controller output configured to control the converter of the wireless power transmitter.

Converters for wireless power transfer and related systems, methods, and devices

Various embodiments relate to digital demodulation for wireless power transmission. A wireless power transmitter includes a transmitter coil and a controller. The transmitter coil is configured to wirelessly couple to a receiver coil of a wireless power receiver to transfer power to the wireless power receiver responsive to a coil current applied to the transmitter coil. The wireless power receiver is configured to modulate at least one electrical condition of the wireless power receiver to modulate the coil current at the transmitter coil. The controller is configured to sample one or more electrical signals of the wireless power transmitter, and digitally demodulate the sampled one or more electrical signals to obtain a communication received from the wireless receiver responsive to the modulation of the at least one electrical condition of the wireless power receiver.

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Chandler, AZ, United States of America

Santosh Bhandarkar