Systems, methods and apparatus for wireless charging are disclosed. A charging device has a charging circuit that includes a charging coil located proximate to a surface of the charging device, a pulse generating circuit, and a controller. The pulse generating circuit may be configured to provide a pulsed signal to the charging circuit, where each pulse in the pulsed signal includes a plurality of cycles of a clock signal that has a frequency greater or less than a nominal resonant frequency of the charging circuit. The controller may be configured to detect a change in resonance of the charging circuit based on a difference in response of the charging circuit to first and second pulses transmitted in the pulsed signal. The controller may be further configured to determine that a chargeable device has been placed in proximity to the charging coil based on the difference in responses.

A power transmission device includes a communication unit that transmits a power capability information transmission request via a communication channel and receives power capability information in response to the power capability information transmission request. The power transmission device also includes a processing unit that sets a parameter based on the power capability information. Further, the power transmission device includes a power transmission unit that wirelessly transmits power using the parameter. The communication unit transmits the power capability information transmission request before the power transmission unit wirelessly transmits the power.

A method for decoding a data stream carried by a modulated signal includes receiving the modulated signal. The modulated signal is modulated according to a protocol belonging to a group of protocols including at least three protocols. The method further includes extracting a clock signal from the received modulated signal, detecting the protocol, and decoding the data stream according to the detected protocol using the extracted clock signal.

A wireless communication system includes a first coupler having a first pair of electrodes and second coupler having a second pair of electrodes that at least partially oppose the first pair of electrodes. A transmission circuit applies a differential signal to the first coupler. A reception circuit receives a differential signal output from the second coupler based on electromagnetic coupling between the first coupler and the second coupler. A distance between centroids of the first pair of electrodes differs from a distance between centroids of the second pair of electrodes.

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.

Example embodiments of systems and methods for data transmission system between transmitting and receiving devices are provided. In an embodiment, each of the transmitting and receiving devices can contain a master key. The transmitting device can generate a diversified key using the master key, protect a counter value and encrypt data prior to transmitting to the receiving device, which can generate the diversified key based on the master key and can decrypt the data and validate the protected counter value using the diversified key.

Disclosed herein is a coil unit that includes a coil formed by spirally winding a conductive wire, a capacitor electrically connected to the coil, a magnetic member covering the coil in an axial direction of the coil, a first metal shield covering the coil with the magnetic member interposed therebetween, and a second metal shield disposed between the magnetic member and the first metal shield so as to form a space for housing the capacitor. The second metal shield is disposed so as to be thermally connected to the first metal shield. An outer dimension of the second metal shield as viewed in the axial direction of the coil is equal to or smaller than an outer dimension of the magnetic member.

A memory device includes a non-volatile memory and a controller. The controller is configured to control the non-volatile memory and includes a receiving circuit configured to receive first data from an external device, a converting circuit configured to convert the first data received by the receiving circuit to second data having a data size equal to or smaller than a data size of the first data, and a writing circuit configured to write the second data converted by the converting circuit in the non-volatile memory.

Data frames, including bursts of an active load modulation (ALM) carrier signal generated from a modulation of an underlying carrier, are transmitted from an object to a reader. Synchronizing a reader carrier signal and the ALM carrier signal includes: prior to transmission of each data frame and between some of the bursts of the ALM carrier signal of each data frame, performing a closed-loop control of an output signal of a main oscillator onto a phase and a frequency of the reader carrier signal; estimating a ratio between a frequency of the output signal of the main oscillator and a frequency of a reference signal produced by a reference oscillator; and during each burst of the ALM carrier signal of each data frame, performing a closed-loop control in frequency only of the output signal of the main oscillator onto the reference frequency of the reference signal corrected by the ratio.

A fixing element for electrical devices, wherein at least one electrical device can be fixed to the fixing element, has at least one coupler, which forms at least one coupling to the at least one electrical device fixed to the fixing element, via which coupling electrical energy and/or data can be transmitted to the at least one electrical device, wherein the coupling is a capacitive and/or inductive coupling. In addition, equipment includes such a fixing element and a least one electrical device, which is fixed to the electrical element.