Abstract: An integrated circuit, includes: an input configured to receive an induced signal that is modulated according to a protocol belonging to the group including protocols using ASK modulation and protocols using OOK modulation; a detection circuit configured to detect the modulation of the induced signal; a decoding circuit configured to detect the protocol; a configurable limiter configured to limit a level of the induced signal and having a first configuration adapted to protocols using ASK modulation and a second configuration adapted to protocols using OOK modulation; and a control circuit configured to set the limiter in the first configuration until a protocol is detected, and to switch the limiter from the first configuration to the second configuration in response to a protocol using OOK modulation being detected.

Abstract: An RFID transponder includes a coding and modulation unit that generates a transmission signal by modulating an oscillator signal with an encoded bit signal. During a first and a second time segment, the encoded bit signal assumes a first and a second logic level, respectively. The transmission signal includes a first signal pulse having a first phase within the first time segment and a second signal pulse having a second phase that is shifted with respect to the first phase by a predefined phase difference within the second time segment. The transmission signal is paused for a pause period between the first and the second signal pulse. The pause period is shorter than a mean value of a period of the first time segment and a period of the second time segment.

Abstract: An RFID transponder includes a coding and modulation unit that generates a transmission signal by modulating an oscillator signal with an encoded bit signal. During a first and a second time segment, the encoded bit signal assumes a first and a second logic level, respectively. The transmission signal includes a first signal pulse having a first phase within the first time segment and a second signal pulse having a second phase that is shifted with respect to the first phase by a predefined phase difference within the second time segment. The transmission signal is paused for a pause period between the first and the second signal pulse. The pause period is shorter than a mean value of a period of the first time segment and a period of the second time segment.

Abstract: In some embodiments, a contactless communication device includes an antenna, and a driving stage having a power supply terminal configured to receive a power supply voltage, where the driving stage is configured to deliver a current to the antenna. The device further includes a monitoring circuit configured to monitor the power transmitted by the antenna. The monitoring circuit is configured, in the presence of a request for a reduction in a current level of transmitted power, to reduce the power supply voltage of the driving stage down to a target value corresponding to a new level of the transmitted power less than the current level.

Abstract: An RFID transponder device has antenna terminals for coupling an antenna system to the device. A transmitter and a receiver are coupled to the antenna terminals. The device has at least one damping resistance connected to at least one of the antenna terminals. The at least one damping resistance is connected, depending on a voltage swing at the antenna terminals during a transmission burst period, either together with a serially connected switch in parallel to the antenna terminals that are coupled to the receiver, or together with a parallel connected switch between one of the antenna terminals and a terminal of the transmitter. A damping control is configured to activate the at least one damping resistance during a damping period after the transmission burst period by controlling the respective switch.

Abstract: In an embodiment, a carrier signal generation circuit can be used for a Radio-frequency identification (RFID) transponder device. A frequency divider circuit has a first input to receive a first frequency signal, a second input to receive a division ratio signal, and an output to provide a carrier signal as a function of the first frequency signal and the division ratio signal. A phase difference circuit has a first input to receive an analog reader device carrier signal, a second input to receive a signal based on the first frequency signal and an output to provide a digital phase difference signal as a function of the reader device carrier signal and the signal based on the first frequency signal. A signal processor has an input coupled to the output of the phase difference circuit.

Abstract: A communication device (10) comprises a conductor (11), a transceiver (12) coupled to the conductor (11) and a data processing unit (13) that is coupled to the transceiver (12). The communication device (10) is configured to determine a strength signal (ST) depending on a receiver signal (SR) received via the conductor (11) and to determine a proximity signal (SP) depending on a proximity of a body to the communication device (10). The data processing unit (13) is configured to generate a disable signal (STO) depending on at least a value of the strength signal (ST) and on at least a value of the proximity signal (SP).

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.

Abstract: A circuit includes an antenna circuit including a number of capacitors and an inductor. The antenna circuit is configured to transmit an output signal upon receiving an input transmit signal. A first control block is configured to transmit an enabling signal upon detecting a presence of a supply voltage at a feeding terminal of the actively transmitting tag in response to the actively transmitting tag being inserted into a host device. A VCO is configured to generate the input transmit signal with the frequency of the interrogator carrier signal upon receiving the enabling signal from the first control block and upon receiving the control voltage from the memory. A second control block is configured to enable a subset of the plurality of capacitors of the antenna circuit upon receiving the enabling signal from the first control block.

Abstract: A transponder communicates with a reader using active load modulation. The transponder includes a digital phase locked loop (DPLL), which, in operation, generates an active load modulation (ALM) carrier clock synchronized to carrier clock of the reader. Between transmission of data frames, the DPLL is placed in a lock mode of operation in which a feedback loop of the DPLL is closed. Within a transmitted data frame having a duration, the DPLL is placed, for the duration of the transmitted data frame, in a hold mode of operation in which the feedback loop is opened. A phase of the ALM carrier clock is adjusted at least once during the duration of the transmitted data frame.

Abstract: In some embodiments, a contactless communication device includes an antenna, and a driving stage having a power supply terminal configured to receive a power supply voltage, where the driving stage is configured to deliver a current to the antenna. The device further includes a monitoring circuit configured to monitor the power transmitted by the antenna. The monitoring circuit is configured, in the presence of a request for a reduction in a current level of transmitted power, to reduce the power supply voltage of the driving stage down to a target value corresponding to a new level of the transmitted power less than the current level.

Abstract: A near field communication (NFC) method includes activating an NFC device second device in response to a first electromagnetic field generated by a nearby NFC device. The NFC device generates a second electromagnetic field after being activated. The first NFC device can detect the second electromagnetic field and initiate a near field communication process.

Abstract: A circuit of an actively transmitting tag includes an antenna, a digitizer, a voltage-controlled oscillator (VCO), an output amplifier, a phase-displacement detector, and a regulator. The input of the digitizer connects to the antenna. The outputs of the digitizer and the output amplifier are connected to the input terminals of the phase-displacement detector. The output amplifier connects the output of the VCO to the antenna and the regulator connects the output of the phase-displacement detector to the VCO.

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.

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.

Abstract: Embodiments provide a method for sending a message from an RFID transponder to a reader during a transmission frame using active load modulation, the method comprising. An encoded bit signal has a first logic level during first time segments within the transmission frame and a second logic level during second time segments within the transmission frame. The first time segments include an initial time segment of the transmission frame. A transmission signal is generated based on the encoded bit signal. The transmission signal is generated having a first phase depending on the first logic level during the first time segments, a second phase depending on the second logic level during the second time segments, and the second phase during a time interval preceding the transmission frame.

Abstract: An RFID transponder includes a coding and modulation unit that generates a transmission signal by modulating an oscillator signal with an encoded bit signal. During a first and a second time segment, the encoded bit signal assumes a first and a second logic level, respectively. The transmission signal includes a first signal pulse having a first phase within the first time segment and a second signal pulse having a second phase that is shifted with respect to the first phase by a predefined phase difference within the second time segment. The transmission signal is paused for a pause period between the first and the second signal pulse. The pause period is shorter than a mean value of a period of the first time segment and a period of the second time segment.

Abstract: A circuit includes an antenna circuit including a number of capacitors and an inductor. The antenna circuit is configured to transmit an output signal upon receiving an input transmit signal. A first control block is configured to transmit an enabling signal upon detecting a presence of a supply voltage at a feeding terminal of the actively transmitting tag in response to the actively transmitting tag being inserted into a host device. A VCO is configured to generate the input transmit signal with the frequency of the interrogator carrier signal upon receiving the enabling signal from the first control block and upon receiving the control voltage from the memory. A second control block is configured to enable a subset of the plurality of capacitors of the antenna circuit upon receiving the enabling signal from the first control block.

Abstract: An RFID transponder device has antenna terminals for coupling an antenna system to the device. A transmitter and a receiver are coupled to the antenna terminals. The device has at least one damping resistance connected to at least one of the antenna terminals. The at least one damping resistance is connected, depending on a voltage swing at the antenna terminals during a transmission burst period, either together with a serially connected switch in parallel to the antenna terminals that are coupled to the receiver, or together with a parallel connected switch between one of the antenna terminals and a terminal of the transmitter. A damping control is configured to activate the at least one damping resistance during a damping period after the transmission burst period by controlling the respective switch.

Abstract: According to an embodiment, a method can be performed by a first active near-field communication (NFC) device. The method includes assuming a field detection mode, generating an advertisement pulse, and checking whether a predefined condition is fulfilled. If the checking determines that the predefined condition is fulfilled, the method includes assuming an active mode and communicating with an adjacent active NFC device, and, if the checking does not determine that the predefined condition is fulfilled, the method includes staying in the field detection mode and generating another advertisement pulse.