Abstract: A wireless charging system having a power transmitter may wirelessly transfer power to a power receiver. Shield saturation, such as saturation of a ferrite structure, in the wireless power receiver may occur under some operating conditions. Saturation can lead to disruptive oscillations in power transfer. The power transmitting may include control circuitry for detecting and mitigating saturation.

Abstract: A power supply system can include a regulated converter that receives an input voltage and produces a regulated output voltage; a switched capacitor converter comprising one or more flying capacitors and a plurality of associated switching devices that receives the regulated output voltage of the regulated converter and multiplies it by a selectable conversion ratio; and control circuitry that operates the regulated converter and the switched capacitor converter to change the selectable conversion ratio while limiting inrush current flowing between the one or more flying capacitors of the switched capacitor converter and an output capacitor of the regulated converter.

Abstract: A tail regulated switched capacitor converter can include a plurality of switched capacitor stages each having a flying capacitor and a plurality of switching devices. The plurality of switching devices can include a first group of one or more switches that selectively couple the flying capacitor to one of an input or output voltage rail via a first current path and a second group of one or more switches that selectively couple the flying capacitor to a tail voltage rail via a second current path. The first and second groups of one or more switches can be switched complementarily to one another with a 50% duty cycle. The tail regulated switched capacitor converter can further include a regulated converter coupled to the tail voltage rail that provides voltage regulation of the output voltage rail while carrying half of a full output current of the tail regulated switched capacitor converter.

Abstract: An electronic device selectively operable in a wireless power receiver mode to receive power from a wireless power transmitter and in a wireless power transmitter mode to transmit power to an accessory can include a wireless power transfer coil; a rectifier coupled to the wireless power transfer coil and operable in the wireless power receiver mode to convert an AC voltage induced in the wireless power transfer coil by a wireless power transmitter to a DC voltage for use by the electronic device; an inverter coupled to the wireless power transfer coil and operable in the wireless power transmitter mode to convert a DC voltage to an AC voltage applied to the wireless power transfer coil; and controller and communication circuitry that, responsive to detecting one or more object detection pings from a wireless power transmitter, activates the wireless power receiver mode.

Abstract: Detecting an object in proximity to an electronic device operable in a wireless power receiver (PRx) mode to receive power from a wireless power transmitter (PTx) or in a PTx mode to transmit power to a PRx can include, responsive to detecting the object, attempting to identify the object as one of at least a PRx and a PTx by conducting one or more frequency sweeps to identify one or more resonant frequencies of the object that characterize the object as a PRx or a PTx; responsive to identifying the object as a PRx, activating the PTx mode and transmitting power to the accessory using wireless power transfer circuitry of the electronic device; and responsive to identifying the object as a PTx, activating the PRx mode and receiving power from the PTx using the wireless power transfer circuitry of the electronic device.

Abstract: Determining an indication of coupling between a wireless power transmitting coil of a wireless power transmitter and a wireless power receiving coil of a wireless power receiver can include measuring one or more circuit parameters of the wireless power transmitter with the wireless power receiving coil effectively short circuited; measuring one or more circuit parameters of the wireless power transmitter with the wireless power receiver coil open circuited; and combining the one or more circuit parameters of the wireless power transmitter measured with the wireless power receiving coil effectively short circuited with the one or more circuit parameters of the wireless power transmitter measured with the wireless power receiver coil open circuited.

Abstract: A wireless charging system having a power transmitter may wirelessly transfer power to a power receiver. Shield saturation, such as saturation of a ferrite structure, in the wireless power receiver may occur under some operating conditions. Saturation can lead to disruptive oscillations in power transfer. The power transmitting may include control circuitry for detecting and mitigating saturation.

Abstract: A wireless charging system having a power transmitter may wirelessly transfer power to a power receiver. Shield saturation, such as saturation of a ferrite structure, in the wireless power receiver may occur under some operating conditions. Saturation can lead to disruptive oscillations in power transfer. The power transmitting may include control circuitry for detecting and mitigating saturation.

Abstract: A wireless power system can include a wireless power transmitter and a wireless power receiver. The transmitter can include a transmit coil, an inverter, and inverter control circuitry that can operate one or more switching devices of the inverter to communicate information to the receiver by controlling a delay between receipt of the burst request pulse and initiating operation of the inverter and/or controlling a polarity of a first pulse of the inverter. The receiver can include a receive coil magnetically coupled to the transmit coil, a rectifier, and rectifier control circuitry that initiates a burst request pulse to initiate operation of a transmitter. The rectifier control circuitry can operate one or more switching devices of the rectifier to communicate information to the transmitter by at least one of short circuiting an LC tank including the receive coil or controlling a polarity of the burst request pulse.

Abstract: A wireless power transmitter can include a coil, an inverter coupled to the coil, and control circuitry coupled to the inverter that, responsive to receiving a burst request pulse from a wireless power receiver, initiates inverter operation, driving the coil and powering the receiver. The control circuitry can operate inverter switches so bandwidth of the wireless power transfer signal falls within a specified range by: (a) extending a minimum on time of the switches, (b) modifying pulse width modulation (PWM) drive signals supplied to the switches to shape a coil current burst envelope, and/or (c) modifying PWM signal amplitude supplied to the switches. Modifying the PWM drive signals can include using a symmetrical PWM scheme in which the positive and negative pulses are symmetrical in width on a cycle-by-cycle basis or using a complementary PWM scheme in which the positive and negative pulse widths are complementary on a cycle-by-cycle basis.

Abstract: A wireless charging mat and method of operating the same. The wireless charging mat includes a detection system configured to determine a location and an orientation of an electronic device on the wireless charging mat. The location and orientation are determined based on detected locations of one or more structural features of the electronic device. The wireless charging mat is operated according to the detected location and orientation.

Abstract: A wireless charging system having a power transmitter may wirelessly transfer power to a power receiver. Shield saturation, such as saturation of a ferrite structure, in the wireless power receiver may occur under some operating conditions. Saturation can lead to disruptive oscillations in power transfer. The power transmitting may include control circuitry for detecting and mitigating saturation.

Abstract: A wireless charging system having a power transmitter may wirelessly transfer power to a power receiver. Shield saturation, such as saturation of a ferrite structure, in the wireless power receiver may occur under some operating conditions. Saturation can lead to disruptive oscillations in power transfer. The power transmitting may include control circuitry for detecting and mitigating saturation.

Abstract: A wireless charging mat and method of operating the same. The wireless charging mat includes a detection system configured to determine a location and an orientation of an electronic device on the wireless charging mat. The location and orientation are determined based on detected locations of one or more structural features of the electronic device. The wireless charging mat is operated according to the detected location and orientation.

Abstract: A wireless charging system having a power transmitter may wirelessly transfer power to a power receiver. Shield saturation, such as saturation of a ferrite structure, in the wireless power receiver may occur under some operating conditions. Saturation can lead to disruptive oscillations in power transfer. The power transmitting may include control circuitry for detecting and mitigating saturation.

Abstract: A wireless power system has a wireless power transmitting device and a wireless power receiving device. The devices in the wireless power system may communicate using in-band communication. The wireless power transmitting device may transmit data to the wireless power receiving device using frequency-shift keying (FSK) modulation. The receiving device may not be aware of the transmission rate of the FSK data. The FSK decoder may identify an actual transmission rate of the incoming bits and decode the wireless power signals into subsequent bits using the actual transmission rate.

Abstract: A device includes a charge controller to regulate a battery output voltage based on an input voltage and an input current received from a charging circuit. A loop controller monitors the input voltage and the input current to generate a feedback signal to adjust the input voltage to the charge controller.

Abstract: A wireless charging system having a power transmitter may wirelessly transfer power to a power receiver. Shield saturation, such as saturation of a ferrite structure, in the wireless power receiver may occur under some operating conditions. Saturation can lead to disruptive oscillations in power transfer. The power transmitting may include control circuitry for detecting and mitigating saturation.

Abstract: A wireless power transmitter can include an inverter that receives a DC input and generates an AC output to drive a wireless power transmit coil coupled to an output of the inverter as well as voltage and current sensors that measure the DC input. The wireless power transmitter can further include a power management accumulator including hardware that receives voltage and current samples from the voltage and current sensors and multiplies corresponding voltage and current samples to produce power samples and memory locations that store corresponding voltage, current, and power samples. The wireless power transmitter can still further include a programmable controller that controls switching devices of the inverter responsive at least in part to the voltage, current and power samples stored in the memory locations of the power management accumulator.

Abstract: A battery case has first and second coils on opposing sides of a battery and has switching circuitry that is coupled between the first and second coils. The battery case has a battery that provides supplemental battery power wirelessly to a wireless power receiving device via the second coil when the switching circuitry is in an open state. The case can also receive power wirelessly with the first coil from a wireless charging mat when the switching circuitry is in the open state. In a closed state, the switching circuitry shorts the first and second coils together so that current flowing through the first coil flows through the second coil in series and so that wireless power from the wireless charging mat that is received with the first coil is transmitted wirelessly to the wireless power receiving device using the second coil.