Circuit arrangement and method for increasing the functional range of a transponder

• US 7,436,286 B2
• Filed: 11/30/2004
• Issued: 10/14/2008
• Est. Priority Date: 12/03/2003
• Status: Active Grant

• Current Assignee: Atmel Corporation (Microchip Technology Incorporated)
• Original Assignee: Atmel Germany GmbH (Microchip Technology Incorporated)
• Inventors: Friedrich, Ulrich, Fischer, Martin, Ziebertz, Dirk, Flassnoecker, Volkhard
• Primary Examiner(s): Zimmerman; Brian
• Assistant Examiner(s): BROWN, VERNAL U
• Application Number:
  US11/002,852
• Publication Number:
  US 20050122651A1
• Time in Patent Office: 1,414 Days
• Field of Search: 340/10.1, 340/10.4, 340/572.5, 340/10.51, 340/10.34, 340/572.4, 340/572.1, 340/10.5, 340/825.69, 340/825.72
• US Class Current: 340/10.1
• CPC Class Codes: G06K 19/0701 at least one of the integrated circuit chips comprising an arrangement for power management
• CPC Class Codes: G06K 19/0715 the arrangement including means to regulate power transfer to the integrated circuit
• CPC Class Codes: G06K 19/0723 the record carrier comprising an arrangement for non-contact communication, e.g. wireless communication circuits on transponder cards, non-contact smart cards or RFIDs
• CPC Class Codes: G06K 19/073 Special arrangements for circuits, e.g. for protecting identification code in memory protection against unauthorised use of computer memory G06F12/14

Abstract

A transponder receives its operating energy from an external source such as a radio signal or a battery. Such transponders are used for example in a vehicle or in a remote sensor. The response range of the transponder is increased by converting the received energy into an operating voltage which in turn is used to generate a function voltage required for performing a current function sequence. The generated function voltage is checked to determine at least one characteristic of the generated function voltage. The determined function voltage characteristic, for example a voltage value directly representing the function voltage, is then used to acknowledge or reject a result of performing the function sequence. Thus, the time duration for performing any current function sequence is flexibly adapted to the current requirements of that function sequence, whereby the power consumption of the transponder is optimally reduced and the response range respectively increased.

Claims

1. A circuit arrangement for increasing a functional transmission range of a passive device having an input to receive an operating voltage (Vdd) from a source, said circuit arrangement comprising a voltage converter (3) connected to said input for generating from said operating voltage a function voltage (Vpp) for performing at least one function sequence in said passive device, a voltage processing circuit (4) including a voltage determination circuit (4.7) connected at (3.6) to said voltage converter (3) for determining at least one characteristic of said function voltage (Vpp), said voltage processing circuit (4) further comprising a valuation circuit (4.8) having an input connected to an output of said voltage determination circuit for generating a logic control signal (HVok) based on said at least one characteristic, said circuit arrangement further comprising a first time counter (5) having an input connected to receive said logic control signal (HVok) for limiting a time duration of a performance of said at least one function sequence to a duration actually required for the performance of said at least one function sequence, said valuation circuit further comprising a second time counter connected for confirming or rejecting a function performance controlled by said first time counter.

2. The circuit arrangement of claim 1, wherein said valuation circuit (4.8) comprises a comparator and a source of a reference value (V_REF) connected to one input of said comparator, said comparator having a further input connected to said determination circuit (4.7) for receiving said at least one characteristic of said function voltage (V_PP).

3. The circuit arrangement of claim 1, wherein said determination circuit (4.7) comprises means for generating said at least one characteristic as a voltage representing said function voltage (V_PP).

4. The circuit arrangenient of claim 3, wherein said means for generating comprise a voltage divider for generating a voltage that is said at least one characteristic.

5. The circuit arrangement of claim 4, wherein said voltage divider comprises capacitors for generating said voltage that is said at least one characteristic.

6. The circuit arrangement of claim 1, wherein said first time counter (5) comprises means for counting a first number of time intervals during which said function voltage (V_PP) is capable of performing a function sequence.

7. The circuit arrangement of claim 1, wherein said second time counter (6) comprises means for counting a second number of time intervals that have passed since said generating of said function voltage (V_PP).

8. The circuit arrangement of claim 7, further comprising means for monitoring said second number of time intervals counted by said second time counter (6), and means for terminating and/or rejecting any function sequence in response to said second number of time intervals counted by said second time counter (6) exceeding a predetermined count.

9. The circuit arrangement of claim 6, further comprising means for monitoring said first number of time intervals counted by said first time counter (5), and means for acknowledging a result of a performed function sequence in response to said first number of time intervals counted by said first time counter reaching a predetermined count.

10. The circuit arrangement of claim 1, further comprising a current limiter (2) operatively connected between said operating voltage input and said voltage converter (3) for limiting a switch-on current.

11. The circuit arrangement of claim 10, wherein said current limiter (2) comprises a MOSFET-transistor and a closed control loop connected to supply said logic control signal (HVok) to said MOSFET-transistor.

12. The circuit arrangement of claim 10, wherein said current limiter (2) comprises at least one resistor and capacitor RC-component (R₁, R₂, C₁).

13. The circuit arrangement of claim 12, further comprising switching means for switching said RC-component to change an RC-component characteristic.

14. The circuit arrangement of, claim 1, wherein said voltage processing circuit (4) comprises Schottky-diodes functioning as switches for limiting a dissipation power.

15. The circuit arrangement of claim 1, used in said passive device including any one of a transponder and a remote sensor adapted for responding to an interrogation signal supplied through an electromagnetic field.

16. A method for increasing a transmission range of a passive device which receives its operating voltage from a source, said method comprising the following steps:

a) generating a function voltage out of said operating voltage, said function voltage being sufficient for enabling said passive device to perform at least one function sequence;

b) generating at least one characteristic of said function voltage to provide a logic control signal (HVok) in response to said at least one characteristic,

c) counting in response to said logic control signal (HVok) a first number of time intervals for limiting a performance duration of said at least one function sequence to a time actually required for the performance of said at least one function sequence and

d) counting a second number of time intervals that have passed since generating said function voltage and confirming or rejecting said at least one function sequence if said second time intervals exceed a predetermined count.

17. The method of claim 16, wherein, said at least one characteristic is a characteristic voltage representing said function voltage, and further comprising comparing said characteristic voltage with a reference voltage value.

18. The method of claim 16, further comprising determining, based on said counted first number of time intervals, whether said function voltage has a characteristic required for performing said respective function sequence.

19. The method of claim 18, further comprising acknowledging a function sequence result in response to said first number of time intervals reaching a predetermined count.

20. The method of claim 16, further comprising limiting as a function of time, an input current derived from said source prior to said step of generating said function voltage.

21. The method of claim 20, further comprising performing said current limiting with a closed loop control.

22. The method of claim 16, further comprising performing said at least one function sequence as a programming operation when said function voltage is adequate for said programming operation.