Signal transmission arrangement with a transformer

• US 8,427,852 B2
• Filed: 05/03/2010
• Issued: 04/23/2013
• Est. Priority Date: 05/03/2010
• Status: Active Grant

• Current Assignee: Infineon Technologies Austria Ag (Infineon Technologies AG)
• Original Assignee: Infineon Technologies Austria Ag (Infineon Technologies AG)
• Inventors: Feldtkeller, Martin
• Primary Examiner(s): Donovan, Lincoln
• Assistant Examiner(s): Almo, Khareem E
• Application Number:
  US12/772,744
• Publication Number:
  US 20110267861A1
• Time in Patent Office: 1,086 Days
• Field of Search: None
• US Class Current: 363/64
• CPC Class Codes: H03L 5/00 Automatic control of voltage, current, or power
• CPC Class Codes: H04B 5/266 One coil at each side, e.g. with primary and secondary coils

Abstract

A signal transmission arrangement includes a transformer with a first and a second winding. A damping circuit has an input terminal for receiving an input signal. The damping circuit is coupled to the first winding and is configured to have an electrical resistance that is dependent on the input signal. An oscillator circuit includes the second winding and is configured to provide an oscillating signal. An evaluation circuit is configured to receive the oscillating signal and to provide an output signal that is dependent on an amplitude of the oscillating signal.

Claims

1. A signal transmission arrangement, comprising:

a transformer comprising a first winding and a second winding;

a damping circuit comprising an input terminal configured to receive an input signal, wherein the damping circuit is coupled to the first winding, and wherein the damping circuit is configured to have an electrical resistance dependent on the input signal;

an oscillator circuit comprising the second winding, wherein the oscillator circuit is configured to provide an analog oscillating signal, wherein an amplitude of the analog oscillating signal varies dependent on an output of the damping circuit; and

an evaluation circuit configured to receive the analog oscillating signal, and to provide an output signal that is dependent on the amplitude of the analog oscillating signal.

2. The signal transmission arrangement of claim 1, wherein the oscillator circuit comprises an LC-circuit comprising the second winding and an amplifier coupled to the LC-circuit.

3. The signal transmission arrangement of claim 2, wherein the oscillator circuit comprises a Colpitts oscillator.

4. The signal transmission arrangement of claim 1, wherein the damping circuit comprises:

a variable resistance arrangement comprising a first output terminal coupled to the first winding and a second output terminal coupled to the first winding; and

a drive circuit configured to receive a drive input signal and to generate a drive signal for the variable resistance arrangement dependent on the drive input signal, wherein the drive input signal is dependent on the input signal of the damping circuit.

14. The signal transmission arrangement of claim 4, wherein the damping circuit further comprises:

a control loop comprising a reference circuit configured to receive the drive signal and to provide a reference signal and a controller configured to provide the drive input signal dependent on the input signal and the reference signal.

15. The signal transmission arrangement of claim 14, wherein the reference circuit comprises a transistor arrangement, and wherein the reference signal is dependent on an electrical resistance of the transistor arrangement.

16. The signal transmission arrangement of claim 1, wherein the transformer comprises a coreless transformer.

5. A signal transmission arrangement, comprising:

a transformer comprising a first winding and a second winding;

a damping circuit configured to receive an input signal, wherein the damping circuit is coupled to the first winding, wherein the damping circuit is configured to have an electrical resistance dependent on the input signal, and wherein the damping circuit comprises

a variable resistance arrangement comprising a first output terminal coupled to the first winding and a second output terminal coupled to the first winding, and

a drive circuit configured to receive a drive input signal and to generate a drive signal for the variable resistance arrangement dependent on the drive input signal, wherein the drive input signal is dependent on the input signal;

an oscillator circuit comprising the second winding and configured to provide an oscillating signal;

wherein the variable resistance arrangement comprises a transistor arrangement comprising a plurality of transistors, wherein a transistor of the plurality of transistors comprises a control terminal configured to receive a drive signal and a load path, wherein the load path is coupled between the first output terminal of the variable resistance arrangement of the damping circuit and the second output terminal of the variable resistance arrangement of the damping circuit; and

wherein the drive circuit is configured to generate a drive signal for the plurality of transistors dependent on the drive input signal.

6. The signal transmission arrangement of claim 5, wherein the load paths of the plurality of transistors are connected in parallel between the first output terminal of the variable resistance arrangement of the damping circuit and the second output terminal of the variable resistance arrangement of the damping circuit.

7. The signal transmission arrangement of claim 5, wherein the transistors have different W/L) ratios.

8. The signal transmission arrangement of claim 7, wherein a second W/L ratio of a second transistor is exponentially larger than a first W/L ratio of a first transistor.

9. The signal transmission arrangement of claim 5, wherein a first transistor of the plurality of transistors has a first signal range and a second transistor of the plurality of transistors has a second signal range, and wherein the drive circuit is configured to drive the first transistor such that an on-resistance of the first transistor varies within the first signal range.

10. The signal transmission arrangement of claim 9, wherein the first signal range is adjacent with the second signal range.

11. The signal transmission arrangement of claim 9, wherein the first signal range overlaps with the second signal range.

12. The signal transmission arrangement of claim 5, wherein the drive circuit comprises a plurality of drive units, wherein the plurality of drive units is configured to receive the drive input signal or an inverted drive input signal and to provide a drive signal for the plurality of transistors.

13. The signal transmission arrangement of claim 12, wherein a drive unit of the plurality of drive units comprises an inverter comprising a first transistor and a second transistor, wherein the inverters of the plurality of drive units have different ratios between a W/L ratio of the first transistor and a W/L ratio of the second transistor.

17. A signal transmission method performed using a signal transmission arrangement that comprises a transformer comprising a first winding and a second winding, an oscillator circuit comprising the second winding and configured to provide an analog oscillating signal based on an output of a damping circuit, and the damping circuit connected to the first winding, the method comprising:

receiving an input signal;

damping the input signal comprising varying an electrical resistance of the damping circuit based on the input signal; and

generating the analog oscillating signal, wherein an amplitude of the analog oscillating signal varies based on the damped input signal.

18. The method of claim 17, wherein generating an analog oscillating signal comprises using a Colpitts oscillator.

19. The method of claim 17, wherein damping the input signal further comprises:

generating a drive signal for a plurality of transistors based on a drive input signal; and

applying the input signal to a variable resistance arrangement comprising a first output terminal coupled to the first winding and a second output terminal coupled to the first winding, wherein the variable resistance arrangement comprises a transistor arrangement comprising a plurality of transistors having a control terminal and a load path, wherein the plurality of transistors is configured to receive a drive signal, and wherein the load path of the plurality of transistors is coupled between the first output terminal of the variable resistance arrangement of the damping circuit and the second output terminal of the variable resistance arrangement of the damping circuit.

20. The method of claim 17, wherein the transformer comprises a coreless transformer.