Battery charging via high speed data interface
Systems and methods for charging a mobile device using a high-speed data interface are described. Power may be provided from Transition Minimized Differential Signaling (TMDS) lines when TMDS data is transmitted via a High-Definition Multimedia Interface (HDMI) connection between a transmitter, such as a mobile device, and a receiving device. Power may be provided to the mobile device in exemplary embodiments such that when the transmitter is in idle or power down state, power may be provided from TMDS lines as part of an upstream charging function.
1. A method for charging a battery of a mobile device using a communications interface, the method comprising:
determining via control circuitry if the mobile device has access to a downstream power supply;
in response to the mobile device not having access to the downstream power supply:
transmitting video data via the communications interface, the transmitting the video data causing the mobile device to have access to the downstream power supply;
receiving power from the downstream power supply at a first rate; and
charging the battery of the mobile device using the received power.
2. The method of claim 1 , the communications interface being a high definition multi-media (HDMI) interface.
3. The method of claim 1 , the transmitting of the video data taking place in response to a determination that the mobile device is not sending data via a data line to a receiver coupled to the downstream power supply.
4. The method of claim 1 , the transmitting of the video data further comprising powering down transmitter blocks to reduce a transmitter power consumption.
5. The method of claim 1 , the transmitting of the video data further comprising using a reduced transmitter clock frequency to transmit the video data relative to a normal operation mode.
6. The method of claim 1 , further comprising, when the mobile device has access to the downstream power supply:
receiving power from the downstream power supply at a second rate that is different from the first rate; and
charging the battery of the mobile device using the received power.
7. The method of claim 1 , further comprising:
when the mobile device is not sending data via a data line to a receiver coupled to the downstream power supply and the mobile device has access to the downstream power supply, entering a full-power charging mode; and
when the mobile device is sending data via a data line to a receiver coupled to the downstream power supply and the mobile device has access to the downstream power supply, entering a normal charging mode, the full-power charging mode receiving power at a higher rate than the normal charging mode.
8. A system for charging a battery of a mobile device using a communications interface, the system comprising:
control circuitry configured to determine if the mobile device has access to a downstream power supply;
transmitter circuitry coupled to the control circuitry, the transmitter circuitry being configured, in response to an indicator received from the control circuitry that the mobile device does not have access to the downstream power supply, to transmit video data through the communications interface, the transmitting the video data causing the mobile device to have access to the downstream power supply; and
charging circuitry coupled to the control circuitry, the control circuitry causing the mobile device to receive power from the downstream power supply at a first rate, the charging circuitry providing the received power to the battery of the mobile device.
9. The system of claim 8 , the communications interface being a high definition multi-media (HDMI) interface.
10. The system of claim 9 , the transmitter circuitry transmitting the video data in response to a determination made by the control circuitry that the mobile device is not sending data via a data line to a receiver coupled to the downstream power supply.
11. The system of claim 9 , the control circuitry being further configured to power down transmitter blocks to reduce a transmitter power consumption when the indicator is received from the control circuitry.
12. The system of claim 9 , the control circuitry being further configured to cause the transmitter circuitry to transmit the video data at a reduced transmitter clock frequency relative to a normal operation mode in response to the indicator being received from the control circuitry.
13. The system of claim 9 , the control circuitry being further configured, when the mobile device has access to the downstream power supply, to cause the mobile device to receive power from the downstream power supply at second rate that is different from the first rate, the charging circuitry providing the received power to the battery of the mobile device.
14. The system of claim 9 , the control circuitry being further configured to:
when the mobile device is not sending data via a data line to a receiver coupled to the downstream power supply and the mobile device does have access to the downstream power supply, cause the mobile device to enter a full-power charging mode; and
when the mobile device is sending data via a data line to a receiver coupled to the downstream power supply and the mobile device has access to the downstream power supply, cause the mobile device to enter a normal charging mode, the full-power charging mode receiving power at a higher rate than the normal charging mode.
15. A method for charging a battery of a mobile device using a communications interface, the method comprising:
receiving an input from the mobile device indicating for the mobile device to charge;
charging the mobile device in response to the received input using a full-power charging state when a downstream power supply is available;
interrupting a coupling between the mobile device and the communications interface;
determining via control circuitry if the mobile device has access to the downstream power supply and determining a charge state of the battery;
restoring the coupling between the mobile device and the communications interface when the control circuitry determines to further charge the battery;
in response to the mobile device not having access to the downstream power supply:
transmitting video data via the communications interface, the transmitting the video data causing the mobile device to have access to the downstream power supply;
receiving power from the downstream power supply at a first rate; and
charging the battery of the mobile device using the received power.
16. The method of claim 15 , wherein the interrupting the coupling takes place in response to the end of a predetermined period of time.
17. The method of claim 15 , further comprising:
interrupting a coupling between the mobile device and the communications interface a second time after charging the battery of the mobile device using the received power;
determining via the control circuitry if the mobile device has access to the downstream power supply and determining a second charge state of the battery; and
when the control circuitry determines to further charge the battery:
restoring the coupling between the mobile device and the communications interface a second time;
re-transmitting video data via the communications interface, the transmitting the video data causing the mobile device to have access to the downstream power supply;
receiving power from the downstream power supply at the first rate; and
charging the battery of the mobile device using the received power a second time.
18. The method of claim 15 , the transmitting of the video data causing the mobile device to have access to the downstream power supply further comprising re-activating the downstream power supply at a receiver, and causing power to be available to the mobile device via terminating resistors of the receiver.
19. The method of claim 15 , further comprising controlling the charging the battery of the mobile device using the received power via the control circuitry to prevent overloading of a transmit circuit block.