Constant-drain drive module for use in low-power applications such as camcorders
Original Publication Date: 2005-Dec-09
Included in the Prior Art Database: 2005-Dec-09
Constant-drain drive module for use in low-power applications that eradicates the high power drain when using magnetic disk media as the storage medium.
Constant-drain drive module for use in low -power applications such as camcorders
With the increase in popularity of digital movie recording equipment, it is becoming apparent that the existing storage mechanisms are not ideal. The current technologies (flash RAM) are limited to around 512Mbyte of storage before becoming prohibitively expensive, or (microdrives) require a relatively large amount of power to keep the platters spinning. If you wish to record high-quality footage, you are limited by one or the other of these factors.
It seems unlikely that the production costs of Flash RAM will decrease significantly. Long-term, it seems that using magnetic disk media is going to be the best solution if the power problems can be solved.
This invention seeks to solve the power issues.
The proposed solution is a video-storage cartridge which comprises: 3 or more "batteries"; most of the bits of a laptop hard-disk module (with a few minor adjustments); some controller circuitry; a bank of memory chips.
The aim is to keep the power requirements low and constant, and to maximise the power-efficiency with which data can be written to the device. Power-efficiency of reading from the device hasn't been a design consideration but is relatively easy to solve.
From a data-flow perspective: the host device (camcorder) will send data to this device which will be stored in the bank of memory chips. As the memory bank gets full, the controller circuitry will spin-up the hard-disk then write all of the cached data to disk. The now-written memory is then tagged as empty, the drive spins-down and the process begins again.
From a power perspective, assuming 3 batteries (A B C) with C initially full and the other two empty: while the memory is filling up, battery A is being charged. When the controller detects that it is time to write the data to disk, it uses...