Programmable output devices for controlling signal levels in an RF/ID transponder
First Claim
1. An integrated circuit suitable for use in an RF/ID transponder comprising:
- a driver section having a differential output;
two groups of serially coupled resistors, each group having a first end coupled to the differential output of the driver section and a second end for driving an antenna; and
electrically programmable means for adjusting the total resistance of each of the group of resistors.
6 Assignments
0 Petitions
Accused Products
Abstract
A single integrated circuit for an RF/ID transponder includes a nonvolatile memory portion, which is ideally a ferroelectric memory, digital logic, digital interface circuitry, and differential analog driver circuitry for driving an antenna that is contained within the RF/ID transponder, but external to the integrated circuit. In series with each leg of the differential analog driver circuitry, and also fabricated on the single integrated circuit, are two groups of serially connected resistors. All circuit nodes associated with the resistors are connected to a signal level control logic block that is in communication with the on-chip digital logic block. The signal level control logic block is used to selectively control the output resistance of the driver circuitry such that a proper balance between incoming and outgoing signal levels is achieved. The output resistance can be programmed to several different levels, the granularity of the levels being determined by the number of serially connected resistors used. An optimum code corresponding to the optimum output resistance is stored in a small portion of the on-chip nonvolatile memory. The code can be externally programmed and updated as required by new applications. The code can also be externally programmed to permanently disable the RF/ID transponder by setting the output resistance to an extremely high level or by open circuiting the output resistance altogether.
62 Citations
20 Claims
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1. An integrated circuit suitable for use in an RF/ID transponder comprising:
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a driver section having a differential output; two groups of serially coupled resistors, each group having a first end coupled to the differential output of the driver section and a second end for driving an antenna; and electrically programmable means for adjusting the total resistance of each of the group of resistors. - View Dependent Claims (2, 3, 4, 5)
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6. An RF/ID transponder having externally programmable receive/transmit characteristics comprising:
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an antenna for receiving and transmitting electrical signals; a driver section having a differential output; two groups of serially coupled resistors, each group having a first end coupled to the differential output of the driver section and a second end coupled to the antenna; a nonvolatile memory for storing a code representing the desired resistance value of each of the resistor groups; and means for controlling the total resistance of the resistor groups according to the code stored in the nonvolatile memory. - View Dependent Claims (7, 8, 9, 10, 11, 12, 13, 14, 15, 16)
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17. A method of operating an RF/ID transponder to properly adjust the receive/transmit characteristics of the transponder, the method comprising the steps of:
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transmitting a code to the RF/ID transponder corresponding to a desired output impedance in an antenna driving circuit resident within the RF/ID transponder; storing the code in nonvolatile memory in the RF/ID transponder; and adjusting the output impedance in response to the code stored in the nonvolatile memory. - View Dependent Claims (18, 19, 20)
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Specification