Abstract: A power supply input selection circuit for selecting one of a plurality of power supply inputs to supply power to a driven circuit. The power supply input selection circuit includes a power supply input switching circuit configured to provide operating power to the driven circuit by routing a selected one of the power supply inputs to the driven circuit as a function of power supply selection information; and a logic circuit configured to change the power supply selection information if a default power mode does not match a desired power mode, the logic circuit being further configured to reset the power supply input selection circuit after changing the power supply selection information, the power supply selection information being maintained during the reset, in which the power supply input switching circuit selects a desired one of the power supply inputs after the logic circuit resets the power supply input selection circuit.

Abstract: An antenna interface of a contactless device including a current source configured to provide a current signal which is dependent on a radio frequency field; and a pause detector coupled to the current source and configured to detect a field pause from the current signal and output a field pause signal.

Abstract: The invention relates to a voltage converter comprising a rectification unit and a voltage regulation unit, wherein the input side of the voltage converter can have an AC voltage applied to it, the output side of the voltage converter can have a rectified voltage taken from it, and the voltage regulation unit regulates the power in the voltage converter.

Abstract: The present invention shows a contactless chip card comprising a controllable demodulation unit for demodulating an amplitude-modulated carrier signal, a measuring unit for determining a degree of modulation of the modulated carrier signal, and a control unit for controlling the demodulation unit on the basis of the determined degree of modulation of the carrier signal.

Abstract: An RFID transponder having an adjustable response field strength including a determination circuit formed to determine a quantity which is derivable from a field strength of an electromagnetic field prevailing at the location of the RFID transponder, a comparator formed to compare the determined quantity derived from the field strength with a threshold value, wherein the threshold value is based on the adjustable response field strength, which is higher than the minimum field strength required for the operation of the RFID transponder, and a deactivator formed to deactivate a functionality of the RFID transponder if the derived quantity falls below the threshold value.

Abstract: An RFID transponder having an adjustable response field strength including a determination circuit formed to determine a quantity which is derivable from a field strength of an electromagnetic field prevailing at the location of the RFID transponder, a comparator formed to compare the determined quantity derived from the field strength with a threshold value, wherein the threshold value is based on the adjustable response field strength, which is higher than the minimum field strength required for the operation of the RFID transponder, and a deactivator formed to deactivate a functionality of the RFID transponder if the derived quantity falls below the threshold value.

Abstract: Signal processing circuit including a demodulator that receives a receive signal with signal edges, and outputs a demodulated receive signal with transitions from a first level to a second level or vice versa at signal edges of the receive signal, wherein points of time of the transitions depend on the steepnesses of the signal edges. The circuit also includes an edge evaluator that receives the receive signal, and outputs an evaluation signal which includes information about the steepnesses of the signal edges. The circuit also includes a signal generator that receives the output of the demodulator, receives the output of the edge evaluator, and outputs a corrected demodulated receive signal with transitions whose points of time are set with regard to the points of time of the transitions of the demodulated receive signal based on the evaluation signal in order to reduce influences of different steepnesses of the signal edges.

Abstract: A communication device having a chip card configured to authorize a communication, the chip card having an interface connected to a communication controller via a modified standardized bus communication, a first and at least one second data source configured to connect to the communication controller.

Abstract: A demodulator includes a sampler and a trigger unit. The sampler is configured to sample a carrier signal based on a trigger signal to obtain a demodulated signal. The trigger unit is configured to detect a zero crossing of the carrier signal or an extreme value of an amplitude of the carrier signal. Further, the trigger unit is configured to provide the trigger signal based on the detected zero crossing or the detected extreme value, so that the carrier signal is sampled by the sampler with a predefined phase shift to the detected zero crossing or the detected extreme value. The predefined phase shift is larger than 30° plus an integer multiple of 90° and lower than 60° plus the same integer multiple of 90° in reference to the carrier signal.

Abstract: A demodulator includes a sampler configured to sample a plurality of first amplitude values of a modulated carrier signal using a constant sampling frequency and a plurality of second amplitude values of the modulated carrier signal at different times using the same constant sampling frequency. The constant sampling frequency is equal to a carrier frequency of the modulated carrier signal with a tolerance of +/?1% of the carrier frequency.

Abstract: A passive RFID transponder includes a coder and a modulator. The coder generates a digital coded data stream based on a digital data stream to be transmitted. The digital coded data stream includes an initialization bit sequence having a maximum data frequency of the digital coded data stream. Furthermore, the digital coded data stream changes its value at the latest after a predefined number of bits. The modulator modulates an amplitude of a carrier signal with the digital coded data stream to provide an amplitude-modulated coded signal.

Abstract: A contactless IC device including a detection circuit configured to detect a carrier wave that has been amplitude shift-keying (ASK) modulated with digital data and a shunt circuit configured to regulate the carrier wave to a predetermined voltage level.

Abstract: A contactless device including an contactless communication interface configured to receive a challenge from a contactless reader and a controller configured to generate an enciphered response using elliptic curve cryptology. Moreover, the enciphered response includes the challenge enciphered with a private key stored in non-volatile memory of the contactless device and data can be integrated as part of the challenge and/or the enciphered response.

Abstract: A circuit arrangement for wirelessly exchanging data with a reader device, including an antenna for converting electromagnetic radiation into an antenna voltage, an analogue circuit for demodulating an information signal based on the antenna voltage, and a digital circuit for processing of the information signal and for receiving power from the analogue circuit. The circuit arrangement also includes a decoupling circuit, which is interconnected between the analogue circuit and the digital circuit and provides a decoupling of both circuits.

Abstract: A power supply for a contactless device having a power supply circuit configured to provide an internal power supply voltage, an emergency capacitor circuit having an emergency capacitor, configured to provide a source current during an external field pause, and a power supply regulator configured to regulate the internal power supply voltage and the source current, wherein the emergency capacitor circuit is electrically coupled in parallel with the power supply circuit.

Abstract: A contactless communication device including an energy interface configured to activate the contactless communication device or a contactless communication partner based on a first carrier signal; and a contactless high speed data interface configured to enable data communication between the contactless communication device and the contactless communication partner based on a second carrier signal having a frequency greater than a high frequency (HF).

Abstract: An antenna interface of a contactless device including a current source configured to provide a current signal which is dependent on a radio frequency field; and a pause detector coupled to the current source and configured to detect a field pause from the current signal and output a field pause signal.

Abstract: A contactless device having an energy antenna configured to transmit/receive an energy signal; and a data antenna configured to transmit a data signal. Also, a method for transmitting a contactless signal including transmitting/receiving an energy signal from an energy antenna of a contactless device; and transmitting a data signal from a data antenna of the contactless device.

Abstract: A demodulator is provided for demodulating a phase-modulated data signal. The demodulator includes a phase frequency detector to output a voltage representing a phase difference between a received phase-modulated data signal and a reference clock signal. The voltage is input to first and second phase change detectors, which are provided to measure the phase difference of the phase-modulated data signal during first and second time periods, respectively.

Abstract: A contactless reader including a crystal oscillator configured to generate a first signal having a first frequency, a phase-locked loop configured to generate a crystal-accurate second frequency derived from the first frequency of the first signal, and a signal generator configured to generate a carrier signal having the crystal-accurate second frequency.