Signal Transmission Arrangement with a Transformer

• US 20110267861A1
• Filed: 05/03/2010
• Published: 11/03/2011
• 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
• Granted Patent: US 8,427,852 B2
• Time in Patent Office: Days
• US Class Current: 363/126
• CPC Class Codes: H03L 5/00 Automatic control of voltage, current, or power
• CPC Class Codes: H04B 5/0093 with one coil at each side, e.g. with primary and secondary coils
• 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 having a first and a second winding;

a damping circuit having an input terminal for receiving an input signal, the damping circuit coupled to the first winding and configured to have an electrical resistance that is dependent on the input signal;

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

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

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

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

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

a variable resistance arrangement with output terminals coupled to the first winding; and

a drive circuit configured to receive a drive input signal, and configured to generate at least one 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.

5. The signal transmission arrangement of claim 4,

wherein the variable resistance arrangement comprises a transistor arrangement with a plurality of transistors, each having a control terminal configured to receive a drive signal and a load path, wherein the load paths of the transistors are coupled between the output terminals of the damping circuit;

and

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

6. The signal transmission arrangement of claim 5, wherein the transistors have their load paths connected in parallel and between the output terminals of the damping circuit.

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

8. The signal transmission arrangement of claim 7, wherein the W/L ratios increase exponentially from a transistor having a lowest W/L ratio to a transistor having a highest W/L ratio.

9. The signal transmission arrangement of claim 5, wherein a signal range of the drive input signal is assigned to each of the transistors of the transistor arrangement and wherein the drive circuit is configured to drive each of the transistors such that its on-resistance varies within a given resistance range for values of the drive input signal lying within an assigned signal range.

10. The signal transmission arrangement of claim 9, wherein the signal ranges adjoin one another.

11. The signal transmission arrangement of claim 9, wherein at least two of the signal ranges overlap.

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

13. The signal transmission arrangement of claim 12, wherein each of the drive units includes an inverter with 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.

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

a control loop with a reference circuit that is configured to receive the at least one drive signal and to provide a reference signal and with a controller that is 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 second transistor arrangement, and wherein the reference signal is dependent on an electrical resistance of the second transistor arrangement.

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

17. A signal transmission method performed with a signal transmission arrangement that comprises a transformer having a first and a second winding, an oscillator circuit comprising the second winding and configured to provide an oscillating signal and a damping circuit connected to the first winding, the method comprising:

receiving a first signal to be transmitted;

damping the oscillating signal by varying an electrical resistance of the damping circuit dependent on the first signal; and

generating a second signal that is dependent on an amplitude of the oscillating signal.