An electronic device in a wireless power system may be operable with a removable accessory such as a case. The device may have coplanar power transmitting and power receiving coils. The transmitting coil may be positioned within a central opening of the receiving coil. The removable accessory may have an embedded receiving coil configured to receive wireless power from the transmitting coil of the electronic device. The receiving coil of the electronic device may receive wireless power from a power transmitting device such as charging mat. The receiving coil of the electronic device may operate up to a higher maximum power than the transmitting coil of the electronic device. The power transmitting coil and power receiving coil in the electronic device may operate at different power transmission frequencies. To mitigate crosstalk, the power transmitting coil's operation frequency may be a non-integer multiple of the power receiving coil's operation frequency.

An electronic device in a wireless power system may be operable with a removable accessory such as a case. The device may have coplanar power transmitting and power receiving coils. The transmitting coil may be positioned within a central opening of the receiving coil. The removable accessory may have an embedded receiving coil configured to receive wireless power from the transmitting coil of the electronic device. The receiving coil of the electronic device may receive wireless power from a power transmitting device such as charging mat. The receiving coil of the electronic device may operate up to a higher maximum power than the transmitting coil of the electronic device. The power transmitting coil and power receiving coil in the electronic device may operate at different power transmission frequencies. To mitigate crosstalk, the power transmitting coil's operation frequency may be a non-integer multiple of the power receiving coil's operation frequency.

A power transfer system comprises a patient transport apparatus and a power transfer device. The power transfer system provides convenience and ease of connection between a power source and the patient transport apparatus to provide power to one or more electrically powered devices on the patient transport apparatus or to provide energy for an energy storage device on the patient transport apparatus.

A device for high-frequency communication and for the inductive charging of an apparatus, including a charging surface, at least one charging antenna emitting a magnetic field at a low frequency and a layer of ferromagnetic material. The device includes at least one communication antenna and a printed circuit board. The communication antenna is in the form of a coil locally surrounding the layer with an axis of symmetry located in a plane parallel to the layer. The material of the layer is selected so as to have, at high frequency, an imaginary part with sufficiently high permeability to generate leaks on a surface of the layer extending perpendicular to the layer, while at the same time maintaining, at low frequency, an imaginary part with sufficiently low permeability to allow inductive charging.

A device for high-frequency communication and for the inductive charging of an apparatus, including a charging surface, at least one charging antenna emitting a magnetic field at a low frequency and a layer of ferromagnetic material. The device includes at least one communication antenna and a printed circuit board. The communication antenna is in the form of a coil locally surrounding the layer with an axis of symmetry located in a plane parallel to the layer. The material of the layer is selected so as to have, at high frequency, an imaginary part with sufficiently high permeability to generate leaks on a surface of the layer extending perpendicular to the layer, while at the same time maintaining, at low frequency, an imaginary part with sufficiently low permeability to allow inductive charging.

Embodiments of the present disclosure provide a buck and rectifier circuit, a wireless charging receiver chip, and a wireless charging receiver. The buck and rectifier circuit includes a rectifier module, a charge pump module, a filter unit, and a control unit. The rectifier module includes a first bridge arm unit and a second bridge arm unit, wherein the first bridge arm unit is connected to a non-inverting output terminal of an alternating current signal, and the second bridge arm unit is connected to an inverting output terminal of the alternating current signal. The charge pump module includes a first voltage converter unit and a second voltage converter unit, wherein the first voltage converter unit is connected in parallel to the second voltage converter unit. The control unit is configured to output a first pulse width modulation signal to control on or off of a switch transistor in the rectifier module, and output a second pulse width modulation signal to control on or off of a switch transistor in the charge pump module, such that an operating frequency of the charge pump module is a positive integer multiple of the frequency of the alternating current signal. According to the above method, power conversion efficiency during wireless charging may be improved.

Embodiments of the present disclosure provide a buck and rectifier circuit, a wireless charging receiver chip, and a wireless charging receiver. The buck and rectifier circuit includes a rectifier module, a charge pump module, a filter unit, and a control unit. The rectifier module includes a first bridge arm unit and a second bridge arm unit, wherein the first bridge arm unit is connected to a non-inverting output terminal of an alternating current signal, and the second bridge arm unit is connected to an inverting output terminal of the alternating current signal. The charge pump module includes a first voltage converter unit and a second voltage converter unit, wherein the first voltage converter unit is connected in parallel to the second voltage converter unit. The control unit is configured to output a first pulse width modulation signal to control on or off of a switch transistor in the rectifier module, and output a second pulse width modulation signal to control on or off of a switch transistor in the charge pump module, such that an operating frequency of the charge pump module is a positive integer multiple of the frequency of the alternating current signal. According to the above method, power conversion efficiency during wireless charging may be improved.

An electronic device utilizing a wireless charging system is provided. The electronic device includes a power source, a transmission coil, a full-bridge inverter electrically connected to the power source and the transmission coil, and a control circuit which communicates with an external device through the transmission coil, and controls the full-bridge inverter to transmit a power signal through the transmission coil. The control circuit may: receive, from the external device, a first control signal requesting that the power of the power signal be reduced to less than a specified power, in response to the first control signal, adjust the duty cycle of each of first to fourth gate signals for controlling the full-bridge inverter, and switch to a pulse width modulation (PWM) drive state in which an operation according to a first period and an operation according to a second period are alternately repeated.

An electronic device utilizing a wireless charging system is provided. The electronic device includes a power source, a transmission coil, a full-bridge inverter electrically connected to the power source and the transmission coil, and a control circuit which communicates with an external device through the transmission coil, and controls the full-bridge inverter to transmit a power signal through the transmission coil. The control circuit may: receive, from the external device, a first control signal requesting that the power of the power signal be reduced to less than a specified power, in response to the first control signal, adjust the duty cycle of each of first to fourth gate signals for controlling the full-bridge inverter, and switch to a pulse width modulation (PWM) drive state in which an operation according to a first period and an operation according to a second period are alternately repeated.

A device includes: a wireless power receiver configured to receive wireless power from an external device external to a body; a capacitor configured to store therein the wireless power received by the wireless power receiver; a wireless transceiver configured to transmit, to the external device, information associated with stored energy of the capacitor and scheduled energy to be used; and a processor configured to operate with the stored energy of the capacitor and process a biosignal of the body, wherein an operation of the external device and an operation of the device are synchronized, and a wireless power quantity of the wireless power to be received by the wireless power receiver from the external device is determined based on the information transmitted from the wireless transceiver to the external device.