Method and apparatus for managing power consumption on a bus

Abstract

An information storage device (10) includes a cartridge (14) removably inserted into a cradle (13) that has a drive module (18) releasably coupled to an interface module (17). The interface module can be operatively coupled by a cable (12) to a remote system. Communications through the cable conform to an industry-standard protocol. The storage device can receive power from either the cable or an external power source (31). The interface module can detect a change in the source of its operating power during normal system operation, and ensure that this is reported through the cable.

Description

CROSS-REFERENCE OF RELATED APPLICATION[0001]This application is a reissue of U.S. patent application Ser. No. 09 / 866,568, filed on May 25, 2001, issued on May 31, 2005 as U.S. Pat. No. 6,901,525.TECHNICAL FIELD OF THE INVENTION[0002]This invention relates in general to devices which communicate through a bus, and more particularly, to techniques by which such devices report through the bus the extent to which they provide power to or draw power from the bus.BACKGROUND OF THE INVENTION[0003]Various industry-standard protocols have been developed to facilitate communication between computers and peripherals. In most of these arrangements, multiple devices are coupled to and communicate through some form of bus, which may be one central bus to which all items are coupled, multiple bus sections coupled in a daisy-chain configuration, or some other arrangement. Some of these standards permit a device to draw some or all of its operating power from the bus under certain conditions.[0004]O...

AI Technical Summary

Benefits of technology

"The present invention provides a method and apparatus for a device that can operate from a bus. The device has two coupling sections that can connect to the bus and a power source. The device can operate in different modes and automatically determine which mode it is operating in. The technical effect of this invention is to enable a device to operate from a bus without needing a separate power source, making it more flexible and efficient."

Problems solved by technology

Other devices generate their own operating power, but do not supply any excess power to the bus.

Otherwise, the requesting device will be denied authorization to draw additional power from the bus, and will typically not become fully operational.

While existing approaches of this type have been generally adequate for their intended purposes, they have not been satisfactory in all respects.

As one example, and as noted above, if a device requests additional power from the bus but it is not available, the device will typically not become fully operational.

This can annoy the user, and create dissatisfaction with the manufacturer of the device.

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