Modulator and modulation method for a wireless data transmission device

• US 20070109102A1
• Filed: 01/12/2007
• Published: 05/17/2007
• Est. Priority Date: 07/12/2004
• Status: Active Grant

• Current Assignee: Atmel Corporation (Microchip Technology Incorporated)
• Original Assignee: Atmel Germany GmbH (Microchip Technology Incorporated)
• Inventors: Friedrich, Ulrich, Fischer, Martin, Pangels, Michael
• Granted Patent: US 8,274,370 B2
• Time in Patent Office: Days
• US Class Current: 340/10.400
• 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 7/0008 General problems related to the reading of electronic memory record carriers, independent of its reading method, e.g. power transfer

Abstract

The invention concerns a modulator (M) for data transmission between a transponder and a base station, which amplitude modulates and/or phase modulates a received electromagnetic carrier signal as a function of data to be transmitted, having a control input at which a modulation control signal is present, having a rectifier (GL) circuit for rectifying the received electromagnetic carrier signal which has at least one rectifier stage (S1-S3), having at least one switching device (SE) which is controllable through the modulation control signal and whose output side intervenes in at least one rectifier stage of the rectifier circuit, and by means of which a reference voltage can be applied to at least one node (H1-H3) of said rectifier stage. The invention further concerns a transponder with such a modulator and a modulation method for operating such [a modulator]. The invention concerns a modulator for data communication between a transponder and a base station, which amplitude modulates and/or phase modulates a received electromagnetic carrier signal as a function of data to be transmitted, having a control input at which a modulation control signal is present, having a rectifier circuit for rectifying the received electromagnetic carrier signal which has at least one rectifier stage, having at least one switching device which is controllable through the modulation control signal and whose output side intervenes in at least one rectifier stage of the rectifier circuit, and by means of which a reference voltage can be applied to at least one node of said rectifier stage. The invention further concerns a transponder with such a modulator and a modulation method for operating such a modulator.

Claims

1. A modulator for data transmission between a transponder and a base station, which phase modulates and/or amplitude modulates a received electromagnetic carrier signal in a transponder as a function of data to be transmitted, the modulator comprising:

a rectifier circuit for rectifying the received electromagnetic carrier signal, the rectifier circuit having at least one rectifier stage with at least one circuit node;

at least one circuit node, which does not constitute an input of the rectifier circuit for the electromagnetic carrier signal, being operably connected by a capacitive coupling to an input of the rectifier circuit;

a switching device whose output side intervenes in at least one rectifier stage of the rectifier circuit, at least one circuit node of the rectifier stage, which does not constitute an input of the rectifier circuit for the electromagnetic carrier signal, is connected to the switching device; and

a modulation control device for providing a modulation control signal for a control input of the switching device.

2. The modulator according to claim 1, wherein the rectifier is provided for modulating the carrier signal.

3. The modulator according to claim 1, wherein the switching device applies a control voltage to the circuit node.

4. The modulator according to claim 1, wherein a voltage sensor is provided that is connected to an input of the switching device and to an output of the rectifier.

5. The modulator according to claim 4, wherein the switching device has an evaluation unit, via which the signal of the voltage sensor is combined with the modulation control signal in a logical form.

6. The modulator according to claim 4, wherein there is provided between an output of the voltage sensor and the control device a comparator, to which is applied a reference voltage.

7. The modulator according to claim 1, wherein at least one rectifier stage has a first node with a high HF voltage and has, following the first node, a second node with a second, lower HF voltage than the first node.

8. The modulator according to claim 7, wherein the controllable switching device is connected on the output side to at least one second node of the rectifier circuit.

9. The modulator according to claim 1, wherein the rectifier circuit is a multi-stage rectifier and the controllable switching device intervenes in at least two of the rectifier stages.

10. The modulator according to claim 1, wherein the controllable switching device has at least one controllable switch whose control connection is driven through a control signal and whose controlled path is thus switched in and out by the control signal.

11. The modulator according to claim 10, wherein the controllable switch is a transistor, a MOSFET, a varactor, or a MOS varactor.

12. The modulator according to at least one of claim 10, wherein at least one capacitive element and/or a capacitor is arranged in series with the controlled path of the controllable switch.

13. The modulator according to claim 12, wherein the output of the controllable switch is coupled to the first node through the capacitive element.

14. The modulator according to claim 10, wherein at least one resistive element and/or a resistor is arranged in parallel and/or in series with the controlled path of the controllable switch.

15. The modulator according to claim 14, wherein the output of the controllable switch is coupled to the second node through the resistive element.

16. A transponder for wireless data communication with a base station, the transponder comprising:

a transmitting for transmitting modulated data;

a receiving device for receiving electromagnetic carrier signals; and

at least one modulator for performing, via intervention within a rectifier circuit, phase modulation and/or amplitude modulation as a function of the data that is to be transmitted, the modulator comprising;

the rectifier circuit for rectifying the received electromagnetic carrier signal, the rectifier circuit having at least one rectifier stage with at least one circuit node;

at least one circuit node, which does not constitute an input of the rectifier circuit for the electromagnetic carrier signal, being operably connected by a capacitive coupling to an input of the rectifier circuit;

a switching device whose output side intervenes in at least one rectifier stage of the rectifier circuit, at least one circuit node of the rectifier stage, which does not constitute an input of the rectifier circuit for the electromagnetic carrier signal, is connected to the switching device; and

a modulation control device for providing a modulation control signal for a control input of the switching device.

17. A method for data transmission between a transponder and a base station, the method comprising:

returning, in a transponder, a received electromagnetic carrier signal phase-modulated as a function of data to be transmitted;

generating a modulation control signal by a modulation control device; and

supplying the modulation control signal to a rectifier,

wherein the modulation is accomplished by the rectifier.

18. The method according to claim 17, wherein amplitude modulation is performed in the rectifier by the modulation control signal in addition to the phase modulation.

19. The method according to claim 18, wherein a modulation of the carrier wave is performed in the modulator as a function of a first threshold value or a voltage.

20. The method according to claim 19, wherein amplitude modulation is not performed until a first threshold value has been exceeded.

21. The method according to claim 20, wherein amplitude modulation is not performed until a second threshold value, which has a higher voltage than the first threshold value, has been exceeded.

22. The method according to claim 17, wherein the modulation index is changed as a function of the magnitude of the voltage of the rectifier.