Device and method for adapting speed of a USB device based on available power

• US 7,069,347 B1
• Filed: 09/27/2002
• Issued: 06/27/2006
• Est. Priority Date: 09/27/2002
• Status: Expired due to Fees

• Current Assignee: Monterey Research, LLC (Vector Capital Corporation)
• Original Assignee: Cypress Semiconductor Corporation (Infineon Technologies AG)
• Inventors: Kolokowsky, Stephen H.
• Primary Examiner(s): Park, Ilwoo
• Application Number:
  US10/260,081
• Time in Patent Office: 1,369 Days
• Field of Search: 710/8, 710/10, 710 14- 17, 710/62, 710/72, 710300-302, 710/60, 710/104, 713/100, 713/300, 713/320, 713/340, 713/1, 713/322
• US Class Current: 710/8
• 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 1/32 Means for saving power

Abstract

Disclosed herein is a device and method for adapting an operating speed of a USB peripheral device coupled with a host. In one example, the peripheral device is initially operated at a first operating speed associated with a first power consumption level, and it is determined whether the host will support the peripheral device operating at a second, higher power consumption level. If so, the peripheral device is reconfigured to operate at a second operating speed associated with the second power consumption level. In one example, the peripheral device may be initially operated at an operating speed of approximately 12 Mbps (i.e., full speed USB) so that the peripheral device draws no more than approximately 100 mA of current. In this example, the peripheral device may report a high power descriptor set including a 100 to 500 mA descriptor, and if the host selects the descriptor set, then the peripheral device is can reconfigure itself to operate with an operating speed of approximately 480 Mbps (i.e., high speed USB) so that the peripheral device draws approximately 100 to 500 mA of current. In this manner, the peripheral device can selectively operate in high speed USB mode if the host (or hub) can provide the current needed by the peripheral device to operate at the faster data rates of the high speed USB mode. If not, the peripheral device operates in the full speed USB mode.

Claims

1. A method for adapting an operating speed of a USB peripheral device adapted to be coupled with a host, comprising:

providing for initially connecting the peripheral device to the host;

providing for, upon initial connection of the peripheral device to the host, initially operating the peripheral device at a first operating speed of full speed USB associated with a first power consumption level;

providing for determining whether the host can support the peripheral device operating at a second power consumption level, said second power consumption level being higher than said first power consumption level, said providing for determining operation further comprising;

providing for reporting the peripheral device as having a descriptor set including a high power descriptor; and

providing for determining if the host selects the high power descriptor;

providing for reconfiguring the peripheral device, if the host selects the high power descriptor, to operate at a second operating speed of high speed USB associated with the second power consumption level, the second operating speed being higher than the first operating speed; and

providing for operating the peripheral device at the first operating speed of full speed USB associated with the first power consumption level if the host does not select the high power descriptor.

2. The method of claim 1, wherein the operation of providing for initially operating further comprises:

providing for operating the peripheral device at an operating speed of approximately 12 Mega bits per second (Mbps) so that the peripheral device draws no more than approximately 100 milliamps (mA) of current.

3. The method of claim 1, wherein the operation of providing for reconfiguring the peripheral device further comprises:

providing for operating the peripheral device at an operating speed of approximately 480 Mbps so that the peripheral device can draw approximately 100 to 500 mA of current.

4. The method of claim 1, wherein the first operating speed is approximately 12 Mbps, the second operating speed is approximately 480 Mbps.

5. The method of claim 1, wherein the first power consumption level is approximately 100 mA, and the second power consumption level is approximately 100 to 500 mA.

6. The method of claim 1, wherein the operation of providing for reconfiguring further comprises:

providing for simulating a disconnection of the peripheral device from a USB bus.

7. A USB device for coupling with a host, comprising:

a module for selectively operating the device at a first or second operating speed depending on whether the host will permit the device to draw a requested power consumption level, the module initially operating the device at the first operating speed of full speed USB associated with a first power consumption level when the device is initially coupled with the host,

wherein the module determines whether the host will permit the device to draw the requested power consumption level being higher than said first power consumption level, by reporting the device as having a descriptor set including a 100 to 500 mA descriptor, and the module determines if the host selects the descriptor set;

wherein if the host selects the descriptor set, the module reconfigures the device, by simulating a disconnection to the host, to operate at a second operating speed of high speed USB associated with the requested power consumption level; and

wherein if the host did not select the descriptor set, the module operates the device at the first operating speed of full speed USB associated with the first power consumption level.

8. The device of claim 7, wherein the first operating speed is approximately 12 Mbps and the first power consumption level is approximately 100 mA of current.

9. The device of claim 7, wherein the second operating speed is approximately 480 Mbps and the requested power consumption level is approximately 100 to 500 mA of current.

10. The device of claim 7, wherein the first operating speed is approximately 12 Mbps, the second operating speed is approximately 480 Mbps.

11. The device of claim 7, wherein the requested power consumption level is approximately 500 mA.

12. A device for coupling with a host, comprising:

a first mode of operation including a first operating speed of full speed USB and a first power consumption level;

a second mode of operation including a second operating speed of high speed USB and a second power consumption level; and

a module for selecting whether the device operates using the first mode or the second mode, the module selecting based in part on whether the host permits the device to operate at the second power consumption level;

wherein the module initially operates the device at the first operating speed of full speed USB when the device is initially coupled with the host,

wherein the module determines whether the host will permit the device to draw the requested power consumption level being higher than said first power consumption level, by reporting the device as having a descriptor set including a 100 to 500 mA descriptor, and the module determines if the host selects the descriptor set;

wherein if the host selects the descriptor set, the module reconfigures the device, by simulating a disconnection to the host, to operate at a second operating speed of high speed USB associated with the requested power consumption level; and

wherein if the host did not select the descriptor set, the module operates the device at the first operating speed of full speed USB associated with the first power consumption level.

13. The device of claim 12, wherein the first operating speed is approximately 12 Mbps, the second operating speed is approximately 480 Mbps.

14. The device of claim 12, wherein the first power consumption level is approximately 100 mA or less, and the second power consumption level is approximately 100 to 500 mA.