Synchronization method of an active load modulation clock within a transponder

    公开(公告)号:US10608854B2

    公开(公告)日:2020-03-31

    申请号:US16156155

    申请日:2018-10-10

    Abstract: A method of wireless communication includes transmitting frames from a transponder to a reader and synchronizing between a reader carrier frequency and an active load modulation (ALM) carrier frequency within each transmitted frame. Each transmitted frame includes ALM carrier bursts generated from subcarrier modulation by binary phase shift keying (BPSK) data encoding and producing signal oscillations at a transponder antenna after each ALM carrier burst generation, The synchronizing occurs at each phase change of the data encoding when no burst is generated during a half period of the subcarrier preceding the phase change and a half period of the subcarrier following this phase change. The transponder antenna has a moderate quality factor sufficient to naturally damp the signal oscillations so that the synchronizing is performed without performing any controlled signal oscillations damping.

    IC CARD REGULATOR
    16.
    发明公开
    IC CARD REGULATOR 审中-公开

    公开(公告)号:US20230273634A1

    公开(公告)日:2023-08-31

    申请号:US18158170

    申请日:2023-01-23

    CPC classification number: G05F1/575

    Abstract: In accordance with an embodiment, a linear voltage regulator includes: a first transistor coupled between a first input terminal and an output terminal, the first input terminal adapted to receive a first voltage, and the output terminal adapted to provide a regulated voltage; a second transistor coupled between a second input terminal and the output terminal, the second input terminal adapted to receive a second voltage; and an amplifier of a difference between a third voltage proportional to the voltage at the output terminal and a reference voltage, an output of said amplifier being selectively coupled to a control terminal of the first transistor and to a control terminal of the second transistor, the amplifier being supplied by a fourth voltage corresponding to a highest voltage of the first voltage and the second voltage.

    CONTACTLESS COMMUNICATION DEVICE MODE SWITCHING MANAGEMENT

    公开(公告)号:US20220029660A1

    公开(公告)日:2022-01-27

    申请号:US17385122

    申请日:2021-07-26

    Abstract: An embodiment device comprises a phase locked loop and a frequency locked loop having in common the same controlled oscillator. The device is firstly placed in the card emulation mode at the beginning of a communication between the contactless communication device and a contactless reader, the firstly placing comprising synchronizing within the contactless device, an ALM carrier frequency with a reader carrier frequency by operating at least the phase locked loop, and upon reception by the contactless communication device of an indication sent by the reader indicating a further communication in a peer to peer mode with the reader, the device is secondly placed in the peer to peer mode, the secondly placing including deactivating the phase locked loop and operating the frequency locked loop with a reference clock signal and a frequency set point depending on the reader carrier frequency and the frequency of the reference clock signal.

    Low power mode card detection
    19.
    发明授权

    公开(公告)号:US11228344B2

    公开(公告)日:2022-01-18

    申请号:US16702902

    申请日:2019-12-04

    Abstract: A circuit includes an in-phase/quadrature down converter configured to be coupled to an antenna of a first NFC (near field communication) device. DC cancellation circuitry is coupled at outputs of the converter. Detection circuitry is configured to analyze DC signals output by the DC cancellation circuits to detect the presence of a second NFC device.

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