Multi-standard compliant USB battery charging scheme with detection of host disconnection in ACA-DOCK mode
Techniques for controlling the charging of portable devices are described herein. In an example embodiment, an apparatus comprises a controller coupled to a Universal Serial Bus (USB) port that is configured as a dedicated charging port (DCP). The controller is configured to detect whether a battery-charging (BC) compliant device or a BC non-compliant device is attached to the USB port. When a BC compliant device is detected, the controller controls the charging of the BC compliant device (e.g., by providing a maximum of 1.5 A of charging current). When a BC non-compliant device is detected, the controller controls the charging of the BC non-compliant device by providing a higher (e.g., up to 2.4 A) charging current.
1. An apparatus comprising:
an Universal Serial Bus (USB) port that is configured as a dedicated charging port; and
a controller coupled to the USB port, the controller configured at least to:
detect whether a battery-charging (BC) compliant device or a BC non-compliant device is attached to the USB port based on whether or not a current sink is activated on a data line of the USB port;
control charging of the BC compliant device when the BC compliant device is detected; and
control charging of the BC non-compliant device, when the BC non-compliant device is detected, by allowing an average charging current that is higher than 1.8 A.
2. The apparatus of claim 1 , wherein the controller comprises a first circuit configured to detect whether the BC compliant device or the BC non-compliant device is attached to the USB port, the first circuit including a replica node of on-die elements that terminate a D− line of the USB port.
3. The apparatus of claim 2 , wherein the first circuit includes a voltage source.
4. The apparatus of claim 2 , wherein the controller further comprises a second circuit configured to confirm detection of the BC compliant device when the first circuit detects that the BC compliant device is attached to the USB port.
5. The apparatus of claim 4 , wherein the second circuit is configured to:
disconnect components, coupled at least to the D+ line, that are configured to support BC non-compliant device charging; and
connect a current sink to the D+ line to discharge any spurious charge thereon.
6. The apparatus of claim 1 , wherein the controller is an integrated circuit (IC) in a single-die chip.
7. The apparatus of claim 1 , wherein the controller comprises a disconnect circuit configured to detect a disconnection of the BC compliant device from the USB port, the disconnect circuit comprising a switch coupled between a ground and a D− line of the USB port.
8. The apparatus of claim 1 , further comprising a docking station, wherein the docking station includes an upstream USB port and the USB port as a downstream USB port, and wherein the controller comprises a detection circuit configured to detect whether a host device is disconnected from the upstream USB port independently of the status of a VBUS line of the upstream USB port.
9. The apparatus of claim 8 , wherein the controller is further configured to:
re-configure the USB port as a communication USB port when the host device is connected to the upstream USB port; and
re-configure the USB port as the dedicated charging port when the host device is disconnected from the upstream USB port.
10. The apparatus of claim 8 , wherein the detection circuit includes a replica node of on-die elements that terminate a D+ line of the upstream USB port.
11. A device comprising:
a first circuit configured to detect whether a battery-charging (BC) compliant device or a BC non-compliant device is attached to a Universal Serial Bus (USB) port based on whether or not a current sink is activated on a data line of the USB port, wherein the USB port is configured as a dedicated charging port; and
a charging circuit configured to control:
charging of the BC compliant device, when the BC compliant device is detected; and
charging of the BC non-compliant device, when the BC non-compliant device is detected, by providing an average charging current that is higher than 1.8 A.
12. The device of claim 11 , wherein the device is an integrated circuit (IC) on a single-die chip.
13. The device of claim 11 , wherein the first circuit includes a voltage source coupled to a replica node of on-die elements that terminate a D− line of the USB port.
14. The device of claim 11 , further comprising a second circuit configured to confirm detection of the BC compliant device when the first circuit detects that the BC compliant device is attached to the USB port, wherein the second circuit is configured to:
disconnect components, coupled at least to the D+ line, that are configured to support BC non-compliant device charging; and
connect a current sink to the D+ line to discharge any spurious charge thereon.
15. The device of claim 11 , further comprising a detection circuit configured to detect a disconnection of the BC compliant device from the USB port, the detection circuit comprising a switch coupled between a ground and a D− line of the USB port.
16. The device of claim 11 , further comprising:
a detection circuit configured to detect whether a host device is disconnected from an upstream USB port, the detection circuit including a replica node of on-die elements that terminate a D+ line of the upstream USB port; and
a re-configuration circuit configured to:
re-configure the USB port as a communication USB port when the host device is connected to the upstream USB port; and
re-configure the USB port as the dedicated charging port when the host device is disconnected from the upstream USB port.
17. A method comprising:
detecting, by a controller, whether a battery-charging (BC) compliant device or a BC non-compliant device is attached to a Universal Serial Bus (USB) port based on whether or not a current sink is activated on a data line of the USB port, wherein the USB port is configured as a dedicated charging port;
charging the BC compliant device when the BC compliant device is detected; and
charging the BC non-compliant device when the BC non-compliant device is detected, by providing an average charging current that is higher than 1.8 A.
18. The method of claim 17 , further comprising confirming detection of the BC compliant device when the controller detects that the BC compliant device is attached to the USB port, wherein confirming the detection of the BC compliant device includes:
disconnecting components, coupled at least to a D+ line of the USB port, that are configured to support BC non-compliant device charging;
connecting a current sink to the D+ line and waiting a first time interval; and
disconnecting the current sink from the D+ line and waiting a second time interval.
19. The method of claim 17 , further comprising detecting, by the controller, a disconnection of the BC compliant device from the USB port.
20. The method of claim 17 , further comprising:
detecting, by the controller, whether a host device is disconnected from an upstream USB port independently of the status of a VBUS line of the upstream USB port;
re-configuring the USB port as a communication USB port when the host device is connected to the upstream USB port; and
re-configuring the USB port as the dedicated charging port when the host device is disconnected from the upstream USB port.