Systems and methods for powering circuits for a communications interface

• US 20090189442A1
• Filed: 07/23/2008
• Published: 07/30/2009
• Est. Priority Date: 05/07/2007
• Status: Active Grant

• Current Assignee: Analogix Semiconductor, Inc. (Beijing Shanhai Capital Management Co., Ltd.)
• Original Assignee: Analogix Semiconductor, Inc. (Beijing Shanhai Capital Management Co., Ltd.)
• Inventors: Chi, Hongwu
• Granted Patent: US 8,063,504 B2
• Time in Patent Office: Days
• US Class Current: 307/2
• CPC Class Codes: H04L 25/028 Arrangements specific to the transmitter end

Abstract

Embodiments include systems and methods of powering data communications transmitter circuitry using current sinked from biasing circuitry used to bias a transmission line between the data communications transmitter circuitry and data communications receiver circuitry. In some embodiments, the current sinked from the biasing circuitry is sourced by a power supply configured to power the data communications receiver circuitry. The current sinked from the biasing circuitry is then re-used to power the data communications transmitter circuitry. The data communications transmitter circuitry can be operated using less power overall than the prior art by re-using the current first used to bias the transmission line to power the data communications transmitter circuitry. Various embodiments include HDMI transceivers, DVI transceivers, and DisplayPort transceivers.

Claims

1. A communications interface comprising:

transmitter circuitry configured to transmit data over a transmission line to a receiver module; and

a power supply configured to at least partially power the transmitter circuitry using current received from the receiver module over the transmission line.

2. The communications interface of claim 1, wherein at least a portion of the transmitter circuitry is biased using the current received from the receiver module over the transmission line.

3. The communications interface of claim 1, wherein the transmitter circuitry is configured to transmit data using a differential signaling protocol.

4. The communications interface of claim 1, wherein the transmitter circuitry is configured to, transmit data at a data rate exceeding 1 megabit per second.

5. The communications interface of claim 1, wherein a length of the transmission line between the transmitter circuitry and the receiver module exceeds approximately 90 centimeters.

6. An electronic circuit comprising:

a current regulator configured to sink a current regulated to be approximately constant; and

a voltage regulator including a power output and configured to regulate a voltage of the power output to be approximately constant, the voltage regulator being configured to receive the current sinked by the current regulator from the current regulator, and configured to supply the current sinked by the current regulator to another electronic circuit through the power output.

7. The electronic circuit of claim 6, further comprising a transmission line and bias circuitry coupled with the current regulator, the bias circuitry configured to bias the transmission line at a bias voltage.

8. The electronic circuit of claim 7, wherein the current regulator is configured to sink the current from the bias circuitry, and the voltage regulator is configured to power a data communications transmitter module configured to transmit data to a data communications receiver module via the transmission line.

9. The electronic circuit of claim 8, wherein the data communications transmitter module is DC-coupled with the data communications receiver module.

10. The electronic circuit of claim 8, wherein the data communications transmitter module is AC-coupled with the data communications receiver module.

11. The electronic circuit of claim 8, wherein the data communications receiver module is configured to source the current sinked by the current regulator from the bias circuitry.

12. An electronic circuit comprising:

transmission line driver circuitry coupled with a transmission line, the transmission line coupled with a first power supply through an impedance;

digital data circuitry coupled with the transmission line driver circuitry and configured to transmit data over the transmission line using the transmission line driver circuitry, the digital data circuitry configured to receive power from a second power supply;

current regulator circuitry coupled with the transmission line driver circuitry and configured to regulate a current received from the first power supply through the transmission line driver circuitry to be approximately constant; and

voltage regulator circuitry coupled with the current regulator circuitry and configured to provide the second power supply having an approximately constant voltage, the second power supply supplying current received from the first power supply through the current regulator circuitry to at least the digital data circuitry.

13. The electronic circuit of claim 12, wherein the digital data circuitry is configured to transmit data over the transmission line using a protocol selected from the group consisting of HDMI, DVI, and DisplayPort.

14. The electronic circuit of claim 12, wherein the transmission line driver circuitry is DC-coupled with receiver circuitry via the transmission line.

15. The electronic circuit of claim 14, wherein the receiver circuitry is configured to be powered by the first power supply.

16. The electronic-circuit of claim 12, wherein the transmission line driver circuitry is AC-coupled with receiver circuitry via the transmission line.

17. The electronic circuit of claim 12, wherein the digital data circuitry is configured to be powered by a combination of the second power supply and a third power supply.

18. A system for data communications comprising:

data communications transmitter circuitry configured to transmit data via a transmission line;

biasing circuitry configured to bias the transmission line at a bias voltage by sinking current from a first power supply; and

voltage regulator circuitry coupled with the biasing circuitry and configured to regulate an approximately constant voltage at a second power supply, the second power supply coupled with the data communications transmitter circuitry, the voltage regulator circuitry being further configured to supply current sinked by the biasing circuitry from the first power supply to the data communications transmitter circuitry via the second power supply.

19. The system of claim 18, wherein the transmission line and the first power supply are coupled with data communications receiver circuitry configured to receive data transmitted by the data communications transmitter circuitry.

20. The system of claim 19, wherein the data communications transmitter circuitry is DC-coupled with the data communications receiver circuitry via the transmission line.

21. The system of claim 19, wherein the data communications receiver circuitry is configured to be powered by the first power supply.

22. The system of claim 18, wherein the data communications transmitter circuitry is configured to transmit data using a differential signaling protocol.

23. The system of claim 18, wherein the data communications transmitter circuitry is configured to transmit video data for display on a video display.

24. The system of claim 18, wherein the data communications transmitter circuitry is configured to be powered by a combination of the second power supply and a third power supply.

25. A method for powering circuits for a communications interface comprising:

biasing a transmission line using biasing circuitry coupled with the transmission line and configured to draw current from a first power supply;

sinking the current from the first power supply through the biasing circuitry;

regulating a voltage of a second power supply to be approximately constant, the second power supply configured to power circuitry for a communications interface; and

supplying current sinked from the first power supply to the circuitry for the communications interface via the second power supply.

26. The method of claim 25, further comprising powering communications transmitter circuitry for the communications interface using the second power supply.

27. The method of claim 25, further comprising powering communications receiver circuitry coupled with the transmission line, the powering being performed by the first power supply.

28. The method of claim 25, further comprising transmitting video data over the transmission line to communications receiver circuitry for display on a video display.

29. The method of claim 25, further comprising regulating the current sinked from the first power supply through the biasing circuitry to be approximately constant.

30. The method of claim 25, further comprising powering communications transmitter circuitry for the communications interface using a combination of power from the second power supply and a third power supply.