Method and apparatus for controlled persistent ID flag for RFID applications
DCFirst Claim
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1. A Radio-Freguency Identification (RFID) transponder including:
- an identification flag circuit to maintain an RFID transponder state, the identification flag circuit including a first capacitor and a digital element coupled to the first capacitor receive a voltage of the first capacitor;
a discharge circuit to drain the first capacitor via a discharge current that is distinct from a semiconductor leakage current; and
,a charge circuit, wherein the semiconductor leakage current is through an open switch of the charge circuit.
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Abstract
A Radio-Frequency Identification (RFID) transponder is provided. The RFID transponder may include a basic ID flag circuit having a VDD voltage node, an output voltage node, and a capacitor coupled to the VDD voltage node and the output voltage node to store an ID flag. A supplemental discharge current circuit coupled to the basic ID flag circuit is provided in order to control persistence duration of the state of the ID flag. The persistence duration of the state of the ID flag is controlled by maintaining supplemental discharge current, which is greater than the leakage current of the basic ID flag circuit.
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Citations
32 Claims
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1. A Radio-Freguency Identification (RFID) transponder including:
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an identification flag circuit to maintain an RFID transponder state, the identification flag circuit including a first capacitor and a digital element coupled to the first capacitor receive a voltage of the first capacitor; a discharge circuit to drain the first capacitor via a discharge current that is distinct from a semiconductor leakage current; and
,a charge circuit, wherein the semiconductor leakage current is through an open switch of the charge circuit.
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2. A Radio-Freguency Identification (RFID) transponder including:
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an identification flag circuit to maintain an RFID transponder state, the identification flag circuit including a first capacitor and a digital element coupled to the first capacitor to receive a voltage of the first capacitor, wherein the digital element is a comparator, the comparator being to output a signal indicative of the identification flap; and a discharge circuit to drain the first capacitor via a discharge current that is distinct from a semiconductor leakage current.
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3. A Radio-Frequency Identification (RFID) transponder including:
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an identification flag circuit to maintain an RFID transponder state, the identification flag circuit including a first capacitor and a digital element coupled to the first capacitor to receive a voltage of the first capacitor; and a discharge circuit to drain the first capacitor via a discharge current that is distinct from a semiconductor leakage current, wherein the discharge circuit is to maintain the discharge current substantially constant with temperature. - View Dependent Claims (4)
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5. A Radio-Frequency Identification (RFID) transponder including:
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an identification flag circuit to maintain an REID transponder state, the identification flag circuit including a first capacitor and a digital element coupled to the first capacitor to receive a voltage of the first capacitor; and a discharge circuit to drain the first capacitor via a discharge current that is distinct from a semiconductor leakage current, wherein the discharge current decreases with temperature. - View Dependent Claims (6)
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7. A Radio-Frequency Identification (RFID) transponder including:
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an identification flag circuit to maintain an RFID transponder state, the identification flag circuit including a first capacitor and a digital element coupled to the first capacitor to receive a voltage of the first capacitor; and
,a discharge circuit to drain the first capacitor via a discharge current that is distinct from a semiconductor leakage current, wherein the discharge current is lower than the semiconductor leakage current.
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8. A Radio-Frequency Identification (RFID) transponder including:
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an identification flag circuit to maintain an RFID transponder state, the identification flag circuit including a first capacitor and a digital element coupled to the first capacitor to receive a voltage of the first capacitor; and a discharge circuit to drain the first capacitor via a discharge current that is distinct from a semiconductor leakage current, wherein the discharge circuit includes; a discharge circuit capacitor to store voltage; and a transconductor circuit coupled to the discharge circuit capacitor to convert voltage stored on a discharge circuit capacitor into the discharge current. - View Dependent Claims (9, 10, 11, 12, 13)
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14. A Radio-Frequency Identification (RFID) transponder including:
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an identification flag circuit to maintain an RFID transponder state, the identification flag circuit including a first capacitor and a digital element coupled to the first capacitor to receive a voltage of the first capacitor; a discharge circuit to drain the first capacitor via a discharge current that is distinct from a semiconductor leakage current; and
,a digital non-volatile memory to control accuracy of the discharge current.
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15. A method to control persistence of an RFID transponder state, comprising:
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charging to a supply voltage a capacitor operative to indicate the RFID transponder state; and draining the capacitor with a discharge current distinct from a semiconductor leakage current from an open switch wherein the discharge current is lower than the semiconductor leakage current. - View Dependent Claims (16, 17, 18, 19, 20, 21, 22, 23)
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24. A device to control persistence of an RFID transponder state, comprising:
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means for charging to a supply voltage a capacitor operative to indicate the RFID transponder state; and means for draining the capacitor with a discharge current distinct from a semiconductor leakage current from an open switch, wherein the discharge current is lower than the semiconductor leakage current. - View Dependent Claims (25, 26, 27, 28, 29, 30, 31, 32)
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Specification