Browse Prior Art Database

Method to Provide Low Power Standby Mode for Online Devices

IP.com Disclosure Number: IPCOM000038998D
Original Publication Date: 1987-Apr-01
Included in the Prior Art Database: 2005-Feb-01
Document File: 1 page(s) / 12K

Publishing Venue

IBM

Related People

Schwartz, RC: AUTHOR

Abstract

A method is described to reduce the standby power required by online devices, thus allowing a smaller power supply to be used. The power requirements of I/O devices (internal or external to the system unit) can be reduced by creating a standby mode of operation. This standby mode is entered and exited by issuing a predetermined control signal sequence (or the lack of control signal sequences) specific to the particular device. The standby mode can also be the default mode. An example of this is the typical 8", 5 1/4", and 3.5" floppy disk drives (FDDs). In the case of the FDD, and interface signal selects the drive to perform some type of operation. Another interface signal instructs the drive to start or stop the spindle motor. For the drive to perform any operation one or both signals must be active.

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Method to Provide Low Power Standby Mode for Online Devices

A method is described to reduce the standby power required by online devices, thus allowing a smaller power supply to be used. The power requirements of I/O devices (internal or external to the system unit) can be reduced by creating a standby mode of operation. This standby mode is entered and exited by issuing a predetermined control signal sequence (or the lack of control signal sequences) specific to the particular device. The standby mode can also be the default mode. An example of this is the typical 8", 5 1/4", and 3.5" floppy disk drives (FDDs). In the case of the FDD, and interface signal selects the drive to perform some type of operation. Another interface signal instructs the drive to start or stop the spindle motor. For the drive to perform any operation one or both signals must be active. If neither signal is active, the drive is waiting. This wait time is defined as Standby Mode. If the drive is used only 5% of the time power is supplied to it, the drive will normally consume much more power than is required to support the system operation. In accordance with the new method, the 3.5" FDD monitors the state of these two interface signals and, if neither is active, reduces the drive's power consumption automatically. In Standby Mode, all logic circuits are powered off except for the circuits that monitor the two interface lines and other sense circuits. In the FDD the logic is broken down in...