USB POWER PORT CONTROL

• US 20150323979A1
• Filed: 05/01/2015
• Published: 11/12/2015
• Est. Priority Date: 05/06/2014
• Status: Active Grant

• Current Assignee: Microchip Technology Incorporated
• Original Assignee: Microchip Technology Incorporated
• Inventors: Kaestner, Clemens
• Granted Patent: US 9,715,271 B2
• Time in Patent Office: Days
• US Class Current: 1/1
• CPC Class Codes: G06F 1/266 Arrangements to supply power to external peripherals either directly from the computer or under computer control, e.g. supply of power through the communication port, computer controlled power-strips
• CPC Class Codes: G06F 1/28 Supervision thereof, e.g. detecting power-supply failure by out of limits supervision
• CPC Class Codes: G06F 1/3253 Power saving in bus
• CPC Class Codes: G06F 1/3287 by switching off individual functional units in the computer system

Abstract

A system, method and device for providing over-current protection to USB ports comprised in a USB hub, whereby a single switch is used to control the power supply to one or more groups of USB ports based on determinations whether the current drawn by a group of USB ports has exceeded a predefined current limit. Embodiments provide the cost savings associated with gang mode power port switching and the reduced stress on USB components and individualized protection of USB ports associated with individual mode power switching. Embodiments utilize a plurality of current measurement units to measure the current drawn by each group of USB ports supported by a switch and further utilize a power port control logic unit to control the switch based on whether the current measurements have exceeded a current limit.

Claims

1. A USB hub comprising a plurality of USB ports and further comprising:

a power element providing a supply of current to the plurality of USB ports;

a plurality of current measurement units, wherein each current measurement unit measures the current drawn by a USB port sub-group, wherein a USB port sub-group is comprised of one or more of the plurality of USB ports; and

a power port control logic unit configured to control the power element, wherein the power port control logic unit receives one or more current measurements from the plurality of current measurement units and wherein the power port control logic unit is further configured to direct the power element to turn off the supply of current to the plurality of USB ports if the received current measurements indicate a current limit has been exceeded by one or more of the USB port sub-groups.

2. The USB hub according to claim 1, wherein the power element is a power switch or a controllable power supply.

3. The USB hub according to claim 1, wherein each of the current measurement units comprises a shunt resistor and a current sensing unit.

4. The USB hub according to claim 1, further comprising:

a plurality of registers, wherein each of the plurality of registers stores a current limit for each USB port sub-group.

5. The USB hub according to claim 4, further comprising:

a comparator configured to retrieve one or more current limits from the plurality of registers and further configured to determine whether one or more of the current measurements exceed one or more of the retrieved current limits.

6. The USB hub according to claim 1, wherein the current measurement unit comprises an analog-to-digital converter.

7. The USB hub according to claim 1, wherein the power port control logic unit is further configured to sum the received current measurements to determine the aggregate current drawn by all USB port sub-groups and wherein the power port control logic unit is further configured to determine if the aggregate current drawn by all USB port sub-groups exceeds a current limit.

8. A method for providing over-current protection comprising:

providing a supply of current to a plurality of USB ports by a power supply element;

measuring the current drawn by each of a plurality of USB port sub-groups, wherein each USB port sub-group comprises one or more USB ports and wherein each USB port sub-group has an associated current measurement unit that measures the current drawn by the one or more USB ports associated with a USB port sub-group;

receiving, by a power port control logic unit, the measured current drawn by each of the plurality of USB port sub-groups; and

directing, by the power port control logic unit, the power supply element to shut off the supply of current to a first USB port sub-group if the received current draw measurement associated with the first USB port sub-group indicate a current limit has been exceeded by the first USB port sub-group.

9. The method according to claim 8, wherein the power element is a power switch or a controllable power supply.

10. The method according to claim 8, wherein each of the current measurement units comprises a shunt resistor and a current sensing unit.

11. The method according to claim 8, further comprising:

retrieving one or more current limits from a plurality of registers wherein each register stores a current limit associated with a USB port sub-group of the plurality of USB sub-groups.

12. The method according to claim 11, further comprising:

comparing a current limit retrieved from the plurality of registers against the measured current draw for the USB port sub-group associated with the retrieved current limit.

13. The method according to claim 8, wherein the current measurement unit comprises an analog-to-digital converter.

14. The method according to claim 8, further comprising:

summing, by the power port control logic unit, the received measured current draws by each USB port sub-group to determine the aggregate current draw by all USB port sub-groups; and

determining, by the power port control logic unit, if the aggregate current drawn by all USB port sub-groups exceeds a current limit.

15. An over-current protection system comprising:

a power element providing a supply of current to a plurality of USB ports;

a plurality of current measurement units, wherein each current measurement unit measures the current drawn by a USB port sub-group, and wherein a USB port sub-group is comprised of one or more of the plurality of USB ports; and

a power port control logic unit configured to control the power element, wherein the power port control logic unit is configured to receive a current measurement from each current measurement unit of the plurality of current measurement units and wherein the power port control logic unit is further configured to direct the power element to turn off the supply of current to a first USB port sub-group if the received current measurements associated with the first USB port sub-group indicates a current limit has been exceeded by one or more USB ports of the plurality of USB ports that comprise the first USB port sub-group.

16. The system according to claim 15, wherein the power element is a power switch or a controllable power supply.

17. The system according to claim 15, wherein each of the current measurement units comprises a shunt resistor and a current sensing unit.

18. The system according to claim 15, further comprising:

a plurality of registers, wherein each of the plurality of registers stores a current limit associated with a USB port sub-group.

19. The system according to claim 18, further comprising:

a comparator configured to retrieve current limits from the plurality of registers and further configured to determine whether the current measurement associated with a USB port sub-group exceed the current limit associated with the USB port sub-group.

20. The system according to claim 15, wherein the power port control logic unit is further configured to sum the received current measurements to determine the aggregate current drawn by all USB port sub-groups and wherein the power port control logic unit is further configured to determine if the aggregate current drawn by all USB port sub-groups exceeds a current limit.