In an embodiment method, an envelope voltage of a resonant capacitor of a wireless power receiver in a wireless charging system may be detected at an output node. One or more parameters of the wireless power receiver may be adjusted in order keep the envelope voltage within a pre-determined voltage range. The one or more parameters includes a capacitance across a receiving coil and the resonant capacitor, or a current of a sub-circuit connected between the output node and a ground. An amplitude shift keying (ASK) carrier signal may be detected at a wireless power transmitter of the wireless charging system and attenuated. A demodulated ASK signal may be generated from the attenuated ASK carrier signal based on peak values of the attenuated ASK carrier signal and a zero-crossing signal generated from the attenuated ASK carrier signal.

Methods, systems, and devices for a functional cover are described. A removable cover (e.g., a functional cover) for a wearable ring device (e.g., a ring wearable) may include one or more electrical components positioned at least partially within the removable cover. In some cases, the functional cover may wireless connect with the ring wearable. The removable cover may further include a first inductive component within the removable cover, where the first inductive component is configured to wirelessly communicate with a second inductive component of the wearable ring device when the removable cover is in a mounted state on the wearable ring device. The first inductive component of the removable cover may be configured to transfer electrical current, data, or both, between the one or more electrical components of the removable cover and one or more additional electrical components of the wearable ring device.

A method for low power communication links between wireless devices is described. The method includes establishing, by a first wireless device, a first magnetic communication link to a source wireless device through a human body. The method also includes establishing, by a second wireless device, a second magnetic communication link to the source wireless device through the human body. The method also includes receiving, by the first wireless device via the first magnetic communication link and the second wireless device via the second magnetic communication link, communications from the source wireless device through the human body.

A magnetic sheet according to an embodiment comprises: a first magnetic sheet part comprising a first surface; a second magnetic sheet part comprising a second surface facing the first surface; and an adhesion part disposed between the first surface and the second surface, wherein the adhesion part comprises a plurality of magnetic particles, and the plurality of magnetic particles may have a concentration gradient in the thickness direction of the adhesion part.

An electronic device may include a transmission circuit and an inductive element. The inductive element may be configured to generate a wireless communication signal based on a current. The transmission circuit may be configured to output the current based on a supply voltage; to increase an intensity of the current, from zero to an increased intensity that is less than or equal to a target value, by alternately repeating a first increase and a first decrease of the intensity of the current, in a first time interval; to decrease the intensity of the current, from the increased intensity to zero, by alternately repeating a second increase and a second decrease of the intensity of the current, in a second time interval.

An electronic device may have a power system. The power system may receive power such as wireless power or wired power and may use a portion of the received power to charge a battery. Power consumption by control circuitry in the device can be adjusted by deactivating or activating processor cores in the control circuitry and by selectively starting or stopping software activities. By selectively reducing power consumption by circuitry in the electronic device other than battery charging circuitry in the power system that is charging the battery, additional power may be made available to charge the battery and/or battery capacity can be extended. The electronic device may reduce non-battery-charging activities in the device in response to information gathered with sensors such as motion and temperature information, information from the power system, information on device location, information on software settings, and other information.

A contactless payment device and method transmits a sequence of magnetic-field pulses directly to two or three magnetic-stripe read heads of a point-of-sale terminal. The baud rate at which the data is transmitted is modulated so that track data for one read head channel will be ignored by another read head channel, based on the change to the baud rate and/or the rate of change in the baud rate to improve acceptance of the transmitted pulses received by the read heads of the point-of-sale terminal.

Example embodiments of systems and methods for data transmission between a contactless card and a receiving application are provided. The transmitting device may include a processor, memory, and communication interface. A receiving application may include instructions for execution on a receiving device having a processor, a memory, a communication interface configured to create a communication field for data communication with the transmitting device, and one or more sensors. Upon movement of the transmitting device, the receiving application is configured to receive, via one or more sensors, feedback information associated with the transmitting device, display one or more instructions regarding the position of the transmitting device relative to the receiving device until the transmitting device enters the communication field. Upon entry into the communication field, the transmitting device is configured to transmit data to the receiving device.

A radiofrequency transmission/reception device includes a first and a second conductive wire element, a first far-field transmission/reception chip and a second near-field transmission/reception chip. The first and the second wire element combine with the characteristic impedance of the second transmission/reception chip in order to form a coupling device associated with the first transmission/reception chip at the operating frequency of the first chip. The first and the second wire element combine with the characteristic impedance of the first transmission/reception chip in order to form a coupling device associated with the second transmission/reception chip at the operating frequency of the second chip.

Systems, methods and apparatus for wireless charging are disclosed. A method for decoding data includes demodulating voltage or current waveform in each tank circuit of a plurality of inductive power transfer circuits to obtain at least one demodulated signal from each tank circuit, capturing a bit sequence from each demodulated signal by clocking signal state of each demodulated signal through a direct memory access (DMA) circuit, streaming bit sequences received from the DMA circuit into a plurality of data streams, and decoding one or more messages from the plurality of data streams.