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Battery calibration mechanism in RAID system Disclosure Number: IPCOM000013004D
Original Publication Date: 2000-Aug-01
Included in the Prior Art Database: 2003-Jun-12
Document File: 2 page(s) / 31K

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Disclosed is a system for the back-up battery in a RAID system to be discharged and charged for calibration of its capacity.

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Battery calibration mechanism in RAID system

     Disclosed is a system for the back-up battery in a RAID system to be discharged and charged for
calibration of its capacity.

           Normally, a RAID(Redundant Arrays of Inexpensive Disks) system has a cache memory for
better performance. And some RAID systems have back-up battery for the cache memory back-up
during AC power outage. And some of the back-up batteries are NiMH type battery. In the
course of time, NiMH battery degrades and the error accumulates in the fuel gauge of the back-up
battery. So, generally, the NiMH type back-up battery is discharged and charged
periodically to measure its real capacity and calibrate the fuel gauge. This function is called
calibration function.

           This disclosure is related to the calibration function of the back-up battery used in a
RAID system. With the proposed method, battery calibration function is performed automatically

and users don't have to care about the calibration function.

            Normally, a RAID system has dual configuration for redundancy. In other words, the RAID
system has two sets of logic cards, power supply units, fan units, back-up batteries, etc..

           Considering the above characteristics of the RAID system, the proposed calibration
function is composed of followings:

1) : Charging circuit
2) : Discharging circuit which uses the fan or blower in the RAID system as the
discharging load. The discharge circuit includes the booster circuit to make the input voltage(Vcc)
of the fan
from the battery.
3) : Software which calibrates the battery periodically in automatic way
4) : Software which provides the user interface for the calibration function
5) : Switch circuit which makes one of the two back-up batteries to back-up all of the
system cache memory during the other back-up battery is calibrated.

              This function is used as follows:
The software 3) monitors the battery status, temperature, time interval from the
previous calibration, charge and discharge history, etc.. If it judges battery calibration is