Smart card receiver and system for pulsed RF fields
First Claim
1. A contactless data transmitter, comprising:
- a tag, the tag comprising an integrated circuit; and
the integrated circuit comprising;
a digital subsystem for processing data received from a target;
an analog subsystem for receiving the data from the target through a pulsed RF field, the analog subsystem comprising a fast-clamping receiver having a shunt regulator configured to protect the integrated circuit from over-voltage transients and a series regulator configured to cause a current passing through the shunt regulator to remain above a minimum threshold,wherein the shunt regulator substantially removes AM voltage fluctuations and accurately adjusts a clamping voltage to be slightly below a breakdown voltage for the integrated circuit; and
a clock circuit configured to generate a fast mode clock signal and a slow mode clock signal.
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Accused Products
Abstract
A fast data transfer collection system using message authentication and contactless RF proximity card technology in non-contact storage and retrieval applications. The system is generally comprised of Host computers (application computer systems), Target radio frequency (RF) terminals, and a plurality of portable Tags (“smart” or “proximity” cards). A Host provides specific application functionality to a Tag holder, with a high degree of protection from fraudulent use. A Target provides control of the RF antenna and resolves collisions between multiple Tags in the RF field. A Tag provides reliable, high speed, and well authenticated secure exchanges of data/information with the Host resulting from the use of a custom ASIC design incorporating unique analog and digital circuits, nonvolatile memory, and state logic. Each Tag engages in a transaction with the Target in which a sequence of message exchanges allow data to be read(written) from(to) the Tag. These exchanges establish the RF communication link, resolve communication collisions with other Tags, authenticate both parties in the transaction, rapidly and robustly relay information through the link, and ensure the integrity and incorruptibility of the transaction. The system architecture provides capabilities to ensure the integrity of the data transferred thus eliminating the major problem of corrupting data on the card and in the system. The architecture and protocol are designed to allow simple and efficient integration of the transaction product system into data/information processing installations.
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Citations
19 Claims
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1. A contactless data transmitter, comprising:
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a tag, the tag comprising an integrated circuit; and the integrated circuit comprising; a digital subsystem for processing data received from a target; an analog subsystem for receiving the data from the target through a pulsed RF field, the analog subsystem comprising a fast-clamping receiver having a shunt regulator configured to protect the integrated circuit from over-voltage transients and a series regulator configured to cause a current passing through the shunt regulator to remain above a minimum threshold, wherein the shunt regulator substantially removes AM voltage fluctuations and accurately adjusts a clamping voltage to be slightly below a breakdown voltage for the integrated circuit; and a clock circuit configured to generate a fast mode clock signal and a slow mode clock signal. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11)
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12. A method of regulating voltage of an integrated circuit in a tag, the method comprising:
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generating the voltage from a pulsed RF field; substantially removing AM voltage fluctuations from the generated voltage; and adjusting a clamping voltage to be slightly below a breakdown voltage for the integrated circuit, adjusting a series impedance to maintain a current above a minimum threshold; generating a first clock signal; generating a second clock signal, wherein the second clock signal is slower than the first clock signal. - View Dependent Claims (13, 14, 15, 16)
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17. A contactless data collection system comprising:
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a target; and a tag positioned in a fixed location and including an integrated circuit, the integrated circuit having; an analog subsystem for receiving the data from the target through the pulsed RF field, the analog subsystem including; a fast-clamping receiver having a shunt regulator, the shunt regulator configured to substantially remove AM voltage fluctuations and to accurately adjust a clamping voltage to be slightly below a breakdown voltage for the integrated circuit, and a series regulator, coupled with the shunt regulator, the series regulator configured to control the current in the shunt regulator to remain above a minimum threshold; and a clock circuit for generating a fast mode clock signal for execution of instructions and a slow mode clock signal for data communication. - View Dependent Claims (18, 19)
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Specification