Contactless communication device with receiver input voltage stabilization
First Claim
1. A contactless communication device, the device comprising:
- a receiver unit having an antenna input for connecting to an antenna, the receiver unit being configured to couple with a transmitting device and to receive an RF signal transmitted by the transmitting device, and to provide to a clock signal derived from the RF signal, the receiver unit being further configured to determine a point of time relating to a position of data within the RF signal;
a programmable impedance circuit including a control terminal, opposing terminals, and a plurality of impedances, the plurality of impedances configured and arranged to respond to a comparator output signal presented at the control terminal by providing a selected impedance across the opposing terminals;
a comparator configured receive the derived clock signal and in response to generate the comparator output signal which is indicative of a relationship between a voltage at the antenna input of the receiver unit and a reference voltage including an indication of whether a peak voltage corresponding to the received RF signal is greater or less than the reference voltage, wherein the selected impedance across the opposing terminals is based on the comparator output signal;
a voltage regulation circuit coupled to the comparator and to the antenna input of the receiver unit, the voltage regulation circuit being configured to repetitively regulate the voltage at the antenna input in a control loop based on the comparator output signal and on a degree of gain sensitivity set by the selected impedance; and
wherein the voltage regulation circuit is configured to separate each repetitive regulation of the voltage at the antenna input by a variable time constant which depends on the point of time and to apply a first voltage regulation step size prior to the point of time determined by the receiver unit and a second voltage regulation step size after the point of time, wherein the control loop has a variable bandwidth that corresponds to the variable time constant, and each of the first voltage regulation step size and the second voltage regulation step size is defined based on the selected impedance.
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Accused Products
Abstract
There is described a contactless communication device. The device comprises (a) a receiver unit (110, 610) having an antenna input (RXn, Vmid, RXp) for connecting to an antenna, the receiver unit (110, 610) being adapted to couple with a transmitting device and to receive an RF signal transmitted by the transmitting device, the receiver unit (110, 610) being further adapted to determine a point of time relating to a position of data within the RF signal, (b) a comparator (120) adapted to generate a comparator output signal (agc_comp) which is indicative of a relation between a voltage at the antenna input (RXn, Vmid, RXp) of the receiver unit (110, 610) and a reference voltage (Vref), and (c) a voltage regulation circuit coupled to the comparator (120) and to the antenna input (RXn, Vmid, RXp) of the receiver unit (110, 610), the voltage regulation circuit being adapted to repetitively regulate the voltage at the antenna input (RXn, Vmid, RXp) based on the comparator output signal (agc_comp). The voltage regulation circuit is adapted to separate each repetitive regulation of the voltage at the antenna input (RXn, Vmid, RXp) by a first time constant prior to the point of time determined by the receiver unit (110, 610) and by a second time constant after the point of time determined by the receiver unit (110, 610), wherein the first time constant is smaller than the second time constant. There is also described a method, a computer program and a computer program product.
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Citations
14 Claims
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1. A contactless communication device, the device comprising:
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a receiver unit having an antenna input for connecting to an antenna, the receiver unit being configured to couple with a transmitting device and to receive an RF signal transmitted by the transmitting device, and to provide to a clock signal derived from the RF signal, the receiver unit being further configured to determine a point of time relating to a position of data within the RF signal; a programmable impedance circuit including a control terminal, opposing terminals, and a plurality of impedances, the plurality of impedances configured and arranged to respond to a comparator output signal presented at the control terminal by providing a selected impedance across the opposing terminals; a comparator configured receive the derived clock signal and in response to generate the comparator output signal which is indicative of a relationship between a voltage at the antenna input of the receiver unit and a reference voltage including an indication of whether a peak voltage corresponding to the received RF signal is greater or less than the reference voltage, wherein the selected impedance across the opposing terminals is based on the comparator output signal; a voltage regulation circuit coupled to the comparator and to the antenna input of the receiver unit, the voltage regulation circuit being configured to repetitively regulate the voltage at the antenna input in a control loop based on the comparator output signal and on a degree of gain sensitivity set by the selected impedance; and wherein the voltage regulation circuit is configured to separate each repetitive regulation of the voltage at the antenna input by a variable time constant which depends on the point of time and to apply a first voltage regulation step size prior to the point of time determined by the receiver unit and a second voltage regulation step size after the point of time, wherein the control loop has a variable bandwidth that corresponds to the variable time constant, and each of the first voltage regulation step size and the second voltage regulation step size is defined based on the selected impedance. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14)
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Specification