Patent Application
20070285036
The present invention is directed, in general, to a power control device and more particularly, to a device and method for reducing the power consumption of a disk drive during start-up.
Most computers, including portable computers, include one or more disk drives as a standard feature. As more and more functions, including traditional computer functions, are integrated into other devices such as mobile telephones, PDAs and digital cameras, these devices are, or will be, increasingly equipped with disk drives. Thus, we now find ourselves with very small computer devices that are being operated at very high speeds. To minimize disk drive data access time, it is important that the drives operate at very high speeds. In fact, the faster these drives rotate, the better the data transfer performance, which means that data can be read off the disk at a faster rate during sequential operations. Increased speed also reduces rotational latency, which is the time the heads reading data from the disk must wait for the correct sector number, thereby improving random operations. For these reasons, the push to increase the spindle speed of disk drive motors continues.
There are several design challenges in increasing disk drive spindle speeds. Some of these challenges include controlling vibration and heat caused by increased drive power consumption. These problems or challenges are usually addressed by designing engineering features into the disk drive. For example, some disk drives with higher spindle speeds require special mounting and cooling features so that they can run without heat, vibration and noise problems. To a certain extent, a trade off is made between spindle speed and power, heat and noise issues. Further, it can be more difficult to overcome such problems when the disk drive is in a smaller device, such as a mobile phone, PDA, or camera.
In many disk drives, particularly those of a recent vintage, much of the power usage is taken up by the disk drive motor. Smaller disk drives typically require relatively little power to keep the disk platters spinning continuously compared to the larger drives. Indeed, due to improved engineering, even the larger drives with fast spindle speeds take considerably less power than did comparably sized drives of a few years ago.
As one skilled in the art will appreciate, when a disk drive is first started, the disk drive motor can draw two to four times the power that typically is required to keep the drive spinning. This is because more energy is required to overcome inertia. Further, with some systems, the large amount of torque required to start a disk drive introduces other problems in addition to the amount of current drain. For example, over torquing can lead to premature gear train failure of the disk drive. Driving the disk drive motor hard will also introduce electrical noise that can interfere with several other aspects of the device.
Accordingly, what is needed is a device to reduce disk drive power consumption on start-up.
To address the above-discussed deficiencies of the prior art, one embodiment of the present invention provides a device to reduce disk drive power consumption during start-up. In one embodiment, the device provides for (1) a speed control module associated with a disk drive motor; and (2) a controller coupled to the speed control module that incrementally increases the spindle rotational speed of the disk drive during start-up.
Thus, embodiments of the present invention provide a device to bring a disk drive up to operating speed while reducing in-rush start-up current. These embodiments can be particularly advantageous when incorporated in a battery powered device with a disk drive, because the disk drive can be incrementally brought up to speed, thereby reducing the load on the battery or batteries, and thus, extending the device's operating life between battery charges or replacement. It gives users of battery powered devices additional operational functionality.
In one embodiment, the controller incrementally increases the spindle rotational speed of the disk drive motor during start-up in a series of predetermined steps. These predetermined steps can be pre-programmed into software that control the rate at which the rotational spindle speed of the disk drive motor is to be increased.
A particularly beneficial embodiment of the invention provides for it to be incorporated within a portable battery powered device. As noted above, this permits the controller to incrementally increase spindle rotational speed of the disk drive motor during start-up and avoid in-rush current with a resultant extension of useable battery life. In some embodiments, the portable battery powered device can be, for example, a mobile telephone, a PDA, an MDA, a pocket PC, a tablet PC, a camera, a digital audio player, such as an MP3 player, or any combination of these devices.
In another embodiment, the controller includes software that drives a digital to analog converter with increasing values. The software can provide for values that are increased in a linear manner or, in another embodiment, in a non-linear manner.
Another embodiment of the invention provides for a method of using a device to reduce disk drive power consumption during start-up. One such embodiment provides for (1) associating a speed control module with a disk drive motor; and (2) causing a controller coupled to the speed control module to incrementally increase the spindle rotational speed of the disk drive during start-up.
Yet another embodiment of the invention provides a method of manufacturing a device to reduce disk drive power consumption. The method, in one embodiment, provides for (1) forming a speed control module and associating it with a disk drive motor; and (2) coupling a controller to the speed control module for incrementally increasing the spindle rotational speed of the disk drive motor during start-up.
The foregoing has outlined various features and embodiments of the present invention so that those skilled in the pertinent art may better understand the detailed description of the invention that follows. Additional features and embodiments of the invention will be described hereinafter that form the subject of the claims of the invention. Those skilled in the pertinent art should appreciate that they can readily use the disclosed conception and specific embodiments as a basis for designing or modifying other structures for carrying out the same purposes of the present invention. Those skilled in the pertinent art should also realize that such equivalent constructions do not depart from the spirit and scope of the invention.
For a more complete understanding of the invention, reference is now made to the following descriptions taken in conjunction with the accompanying drawing, in which:
Referring initially to
The illustrated battery powered device 100 is intended to be representative of a personal digital assistant (PDA) 100. As will be readily understood by those skilled in the relevant art, the present invention can be employed in any one of a number of different types or kinds of portable battery powered devices 100 and still be within the intended scope of the present invention. For example, the portable battery powered device 100 could be a mobile telephone, a mobile digital assistant (MDA), a pocket PC, a tablet PC, a camera, a digital audio player, such as an MP3 player, or the like and still be within the scope of the present invention if an embodiment of the inventive feature described herein is included.
Referring now to
To reduce the effects of in-rush current on start-up, embodiments of the present invention reduce disk drive 110 power consumption by controlling the spindle 135 rotational speed, so that all the battery 210 current is not fed to the disk drive motor 130 at once during start-up. The speed control module 120, associated with the disk drive motor 130, controls the amount of current pushed through on start-up. Coupled to the speed control module 120 is the controller 140, to incrementally increase spindle 135 rotational speed.
In one embodiment of the invention, the controller 140 includes software 230 for driving a digital to analog converter 240 with increasing voltage values. In an associated embodiment, the values are increased in a linear manner while in another the values are increased in a non-linear manner. When increased in a non-linear manner, the spindle 135 rotational speed can be increased in a series of predetermined steps. For example, if the operational spindle 135 speed is 10,000 rpm, the rotational speed can be increased in sequential steps from 4,800 rpm, to 5,400 rpm, to 7,200 rpm, and, finally to the operational speed of 10,000 rpm.
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In one embodiment of the invention, the method calls for a provide controller with software step 540. In this step, the controller is provided with software driving a digital to analog converter with increasing voltage values. This software can provide for increasing values in a linear manner or in a non-linear manner or a combination thereof.
A useful embodiment calls for an install in device step 550 wherein the invention is incorporated within a portable battery powered device. This portable battery powered device can be selected from the group consisting of a mobile telephone, a PDA, an MDA, a pocket PC, a tablet PC, a camera, or a digital audio player and be within the scope of the intended invention. The method concludes with an end step 560
The present invention also includes several additional embodiments, which embodiments are readily apparent to those skilled in the pertinent art from the forgoing description. Although the present invention has been described in detail, those skilled in the pertinent art should understand that they can make various changes, substitutions and alterations herein without departing from the spirit and scope of the invention in its broadest form.
