Systems and methods for powering circuits for a communications interface
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 may be operated using less power overall 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.
1. An electronic circuit comprising:
a current regulator sinking a current, the current regulator regulating the current sinked to be approximately constant;
a bias circuitry coupled with the current regulator, the bias circuitry biasing a transmission line at a bias voltage and supplying the current to the current regulator; and
a voltage regulator including a power output and regulating a voltage of the power output to be approximately constant, the voltage regulator receiving the current sinked by the current regulator from the current regulator, and being coupled to another electronic circuit, the voltage regulator supplying the current sinked by the current regulator to the other electronic circuit through the power output, the voltage regulator powering a data communications transmitter module transmitting data to a data communications receiver module via the transmission line.
2. The electronic circuit of claim 1 , wherein the data communications transmitter module is DC-coupled with the data communications receiver module.
3. The electronic circuit of claim 1 , wherein the data communications transmitter module is AC-coupled with the data communications receiver module.
4. The electronic circuit of claim 1 , wherein the data communications receiver module provides the current sinked by the current regulator from the bias circuitry.
5. A method comprising:
regulating a sink current by a current regulator, the sink current being regulated to be approximately constant;
biasing a transmission line at a bias voltage by bias circuitry coupled with the current regulator, the current regulator to sink the current from the bias circuitry; and
regulating a voltage of a power output by a voltage regulator, the voltage of the power output regulated to be approximately constant, the voltage regulator receiving the current sinked by the current regulator from the current regulator, and being coupled to another electronic circuit, the voltage regulator supplying the current sinked by the current regulator to the other electronic circuit through the power output, the voltage regulator powering a data communications transmitter module transmitting data to a data communications receiver module via the transmission line.
6. The method of claim 5 , wherein the data communications transmitter module is DC-coupled with the data communications receiver module.
7. The method of claim 5 , wherein the data communications transmitter module is AC-coupled with the data communications receiver module.
8. The method of claim 5 , wherein the data communications receiver module provides the current sinked by the current regulator from the bias circuitry.