Universal serial bus (USB) cable type detection and control techniques
Universal Serial Bus (USB) cable type detection and control techniques are disclosed. In an exemplary aspect, a device connected to a cable detects whether the cable is a legacy cable (i.e., a Type-A to Type-C cable). If the cable is a legacy cable, the device determines an appropriate current to draw based on whether the cable is compliant with the USB Type-C specification or non-compliant. Additional exemplary aspects of the present disclosure determine whether a connector adaptor has been put on a legacy cable and determines an appropriate current to draw based on the capabilities of the legacy cable. Still further aspects of the present disclosure evaluate not only the cable to see if the cable limits the current draw, but also evaluate a device at a distal end of the cable to verify if and how current may be drawn by such remote device from a mobile terminal.
1. A method for controlling current levels on a Universal Serial Bus (USB) cable, comprising:
detecting whether a cable is a legacy Type-A to Type-C cable;
detecting whether the cable is compliant or not compliant with a USB Type-C specification; and
setting a current draw based on whether the cable is legacy or not legacy and on whether the cable is compliant or not compliant with the USB Type-C specification.
2. The method of claim 1 , wherein detecting whether the cable is compliant or not compliant with the USB Type-C specification comprises determining a voltage level at a command and control (CC) input.
3. The method of claim 1 , wherein detecting whether the cable is the legacy Type-A to Type-C cable comprises detecting whether a voltage is initially present at a Vbus input.
4. The method of claim 1 , further comprising determining if an attached charger is a standard downstream port (SDP) or a charging downstream port (CDP).
5. The method of claim 4 , further comprising concluding the cable is non-compliant with the USB Type-C specification if the attached charger is the SDP or the CDP.
6. The method of claim 1 , wherein setting the current draw comprises limiting the current draw to no more than 1.5 amperes (A) if the cable is a non-compliant legacy cable.
7. The method of claim 1 , wherein the method is performed in a dongle attached between the cable and a device.
8. A dongle comprising:
a first interface configured to attach to a Universal Serial Bus (USB) cable;
a second interface configured to plug into a USB device; and
a control system operatively coupled to the first interface and the second interface and configured to:
detect whether a cable plugged into the first interface is a legacy Type-A to Type-C cable;
detect whether the cable is compliant or not compliant with a USB Type-C specification; and
set a current draw based on whether the cable is legacy or not legacy and on whether the cable is compliant or not compliant with the USB Type-C specification.
9. A Universal Serial Bus (USB) device comprising:
a receptacle configured to receive a USB cable; and
a control system operatively coupled to the receptacle and configured to:
detect whether a cable plugged into the receptacle is a legacy Type-A to Type-C cable;
detect whether the cable is compliant or not compliant with a USB Type-C specification;
detect whether a remote device on a remote end of the cable is compliant or not compliant with the USB Type-C specification; and
set a current draw based on whether the cable is legacy or not legacy and on whether the cable is compliant or not compliant with the USB Type-C specification.
10. The USB device of claim 9 , wherein the control system comprises a power management integrated circuit (PMIC).
11. The USB device of claim 10 , wherein the PMIC comprises a first crude sensor associated with a command and control (CC) input of the receptacle, the first crude sensor configured to sense first voltage levels at the CC input.
12. The USB device of claim 11 , wherein the PMIC comprises a second crude sensor associated with a second CC input of the receptacle, the second crude sensor configured to sense second voltage levels at the second CC input.
13. The USB device of claim 11 , wherein the PMIC further comprises a timer.
14. The USB device of claim 9 , wherein the control system is further configured to set a signal flag in response to voltage levels above a predefined threshold at a Vbus input of the receptacle.
15. The USB device of claim 9 , wherein the receptacle comprises a USB Type-C receptacle.
16. The USB device of claim 9 , wherein the control system is configured to detect whether the cable is compliant or not compliant with the USB Type-C specification by determining a voltage level at a command and control (CC) input.
17. The USB device of claim 9 , wherein the control system is configured to detect whether the cable is the legacy Type-A to Type-C cable by detecting whether a voltage is initially present at a Vbus input.
18. The USB device of claim 9 , wherein the control system is further configured to determine if an attached charger is a standard downstream port (SDP) or a charging downstream port (CDP).
19. The USB device of claim 18 , wherein the control system is further configured to conclude the cable is non-compliant with the USB Type-C specification if the attached charger is the SDP or the CDP.
20. The USB device of claim 9 , wherein setting the current draw comprises limiting the current draw to no more than 1.5 amperes (A) if the cable is a non-compliant legacy cable.
21. The USB device of claim 9 integrated into a device selected from the group consisting of: a set top box; an entertainment unit; a navigation device; a communications device; a fixed location data unit; a mobile location data unit; a global positioning system (GPS) device; a mobile phone; a cellular phone; a smart phone; a session initiation protocol (SIP) phone; a tablet; a phablet; a server; a computer; a portable computer; a mobile computing device; a wearable computing device; a desktop computer; a personal digital assistant (PDA); a monitor; a computer monitor; a television; a tuner; a radio; a satellite radio; a music player; a digital music player; a portable music player; a digital video player; a video player; a digital video disc (DVD) player; a portable digital video player; an automobile; a vehicle component; avionics systems; a drone; and a multicopter.