Abstract:
A terminal for generating an electromagnetic field adapted to cooperating with at least one transponder when the latter enters its field and including an oscillating circuit adapted to receiving a high-frequency A.C. excitation voltage, circuitry for regulating the signal phase in the oscillating circuit with respect to a reference value, circuitry for determining an instantaneous information relative to the magnetic coupling between the transponder and the terminal, and circuitry for adapting the electromagnetic field power according to at least said present information.
Abstract:
A terminal for generating a high-frequency electromagnetic field by an oscillating circuit, adapted to cooperating with at least one transponder when the transponder enters this field, and a method for establishing a communication between the devices, including circuitry for regulating the signal phase in the oscillating circuit with respect to a reference value and circuitry for evaluating, based on a measurement of the current in the oscillating circuit, the minimum number of transponders present in the field.
Abstract:
The present invention relates to a circuit for controlling a fluorescent lamp, including circuitry that provides a low frequency alternating current to the fluorescent lamp, this circuitry being controlled by a controllable switched-mode current source operating at high frequency.
Abstract:
A device for providing a high d.c. voltage supply and a low d.c. voltage supply. The device includes, in parallel, a first diode connected in series with a capacitor, a rectifier having a polarity opposite to that of the first diode, and a breakover voltage limiter. The terminals of the low d.c. voltage source correspond to the terminals of the capacitor.
Abstract:
A method for managing the power in an electromagnetic transponder in the field of a terminal, including the steps of: evaluating the power consumption of the transponder circuits; and if this power consumption is below a threshold, evaluating the current coupling factor between the transponder and the terminal and, according to the current coupling: causing an increase of the transponder power consumption or causing a detuning of an oscillating circuit of the transponder.
Abstract:
A method for protecting communication between an electromagnetic transponder and a terminal, wherein the transmission of a polling request by the terminal is only allowed when the transponder is in mechanical contact or in quasi-mechanical contact with the terminal.
Abstract:
A method of power recovery by an electromagnetic transponder in the field of a terminal, wherein: a ratio of the current coupling factor of the transponder with the terminal to an optimum coupling position with a resistive load value is evaluated; and a detuning of the oscillating circuit is caused if the ratio is greater than a first threshold greater than or equal to one.
Abstract:
A method of authentication, by a terminal generating a magnetic field, of a transponder located in this field, wherein: first data, relative to the current in an oscillating circuit of the terminal, measured by the terminal for a first value of the resistive load of the transponder, are transmitted to the transponder; second corresponding data are evaluated by the transponder for a second value of the resistive load and are transmitted to the terminal; and said second data are compared with third corresponding data, measured by the terminal for the second value of the resistive load.
Abstract:
A transponder comprising a resonant circuit, comprising an antenna and a capacitor, and at least one memory connected to the resonant circuit via an intermediate circuit, characterized in that the intermediate circuit comprises at least one contact zone for receiving a portion of human body, so that the positioning of a portion of human body on a contact zone modifies the intermediate circuit, capable of switching from a first state in which it does not allow the memory to be read and/or written to a second state in which it allows the memory to be read and/or written when the resonant circuit of the transponder is contactlessly powered by a reader.
Abstract:
A method for protecting communication between an electromagnetic transponder and a terminal, wherein the transmission of a polling request by the terminal is only allowed when the transponder is in mechanical contact or in quasi-mechanical contact with the terminal.