RF device with tamper detection
First Claim
1. A Radio Frequency Identification (RFID) system, comprising:
- communication circuitry for enabling wireless communication with an RF reader;
energy harvesting circuitry for generating an electric current from RF energy;
a status register circuit;
a sensor loop coupled to the RFID system at three pads, the three pads including;
a first pad coupled to a current source, wherein the current source receives the electric current generated by the energy harvesting circuitry,a second pad coupled to the status register circuit, wherein the status register circuit is coupled to the sensor loop for indicating a broken or unbroken status of the sensor loop, anda third pad coupled to ground of the RFID system; and
a nonvolatile memory separate from and coupled to the status register circuit for storing a status of the sensor loop based on the status of the status register circuit;
wherein the communication circuitry is configured to send the stored status of the loop to the RF reader.
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Accused Products
Abstract
A Radio Frequency Identification (RFID) system according to one embodiment includes communication circuitry for enabling wireless communication with an RF reader; energy harvesting circuitry for generating an electric current from RF energy; a sensor loop coupled to the energy harvesting circuitry; and a status register coupled to the sensor loop for indicating a broken or unbroken status of the sensor loop. A method according to one embodiment includes generating an electric current in a Radio Frequency Identification (RFID) device, the current energizing a sensor loop; detecting a status of whether the sensor loop is broken or unbroken; storing the status in at least one of a status register and a nonvolatile memory; receiving a query from an RFID reader for the status; and sending the status to the RFID reader.
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Citations
19 Claims
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1. A Radio Frequency Identification (RFID) system, comprising:
- communication circuitry for enabling wireless communication with an RF reader;
energy harvesting circuitry for generating an electric current from RF energy;a status register circuit; a sensor loop coupled to the RFID system at three pads, the three pads including; a first pad coupled to a current source, wherein the current source receives the electric current generated by the energy harvesting circuitry, a second pad coupled to the status register circuit, wherein the status register circuit is coupled to the sensor loop for indicating a broken or unbroken status of the sensor loop, and a third pad coupled to ground of the RFID system; and a nonvolatile memory separate from and coupled to the status register circuit for storing a status of the sensor loop based on the status of the status register circuit; wherein the communication circuitry is configured to send the stored status of the loop to the RF reader. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9)
- communication circuitry for enabling wireless communication with an RF reader;
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10. A Radio Frequency Identification (RFID) system, comprising:
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communication circuitry for enabling wireless communication with an RF reader; energy harvesting circuitry for generating an electric current from RF energy; a sensor loop coupled to the energy harvesting circuitry; a status register coupled to the sensor loop for indicating a broken or unbroken status of the sensor loop, a nonvolatile memory separate from and coupled to the status register for storing a status of the sensor loop based on the status of the status register, wherein the nonvolatile memory is system memory that is shared for other uses, wherein the RFID system is passive, wherein the sensor loop is external to a housing coupled to the communication circuitry and energy harvesting circuitry, wherein the sensor loop is coupled to a sensor node and also to ground, a first resistor between the energy harvesting circuitry and the sensor node, the sensor loop extending from the first resistor to the status register; and a second resistor between the ground and the sensor node, the second resistor being coupled to the sensor loop at a position on the sensor loop between the first resistor and the status register, the second resistor being directly coupled to sensor loop and to the ground. - View Dependent Claims (11, 12)
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13. A Radio Frequency Identification (RFID) system, comprising:
- communication circuitry for enabling wireless communication with an RF reader;
energy harvesting circuitry for generating an electric current from RF energy;a sensor loop coupled to the energy harvesting circuitry;
a status register coupled to the sensor loop for indicating a broken or unbroken status of the sensor loop, wherein the system is not disabled when the sensor loop is broken;
a nonvolatile memory separate from and coupled to the status register for storing a status of the sensor loop based on the status of the status register; and
a second resistor coupled directly to the ground and the sensor node, wherein the communication circuitry is configured to send the stored status of the loop to the RF reader, wherein the system is configured to store a timestamp in the memory, the timestamp being indicative of a time when the stored status was obtained, wherein the communication circuitry is further configured to send a status of the status register in addition to the stored status, wherein the sensor loop is coupled to a sensor node and also to ground, and further comprising a first resistor between the energy harvesting circuitry and the sensor node. - View Dependent Claims (14, 15, 16, 17)
- communication circuitry for enabling wireless communication with an RF reader;
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18. A method, comprising:
- generating an electric current in a Radio Frequency Identification (RFID) device, the current energizing a sensor loop;
detecting a status of whether the sensor loop is broken or unbroken;
storing the status in both a status register and a nonvolatile memory for later retrieval;
receiving a query from an RFID reader for the status; and
sending the stored status to the RFID reader,wherein the status register is configured to indicate that the sensor loop is unbroken when the sensor loop is repaired after being broken; and
further comprising storing a broken status in the memory when a broken sensor loop is detected even though the status register indicates that the sensor loop is unbroken when the sensor loop is repaired after being broken; and
sending the broken status to the RFID reader, wherein the memory is system memory that is shared for other uses, wherein the status register is configured to indicate that the sensor loop has been broken even when the sensor loop is repaired after being broken. - View Dependent Claims (19)
- generating an electric current in a Radio Frequency Identification (RFID) device, the current energizing a sensor loop;
Specification