System and method of measuring a battery lifetime
US5684404A · kind A · utility
Assignees
Inventor
Key dates
| Filing date | Nov 17, 1995 |
| Grant date | Nov 4, 1997 |
| Priority date | — |
| Expiry date | Nov 17, 2015 |
Classification
- Technology area (CPC G)Physics
- CPC primaryG01R31/3648
- WIPO fieldMeasurement
- WIPO sectorInstruments
Abstract
A voltage gradient measurement device is provided for determining the remaining lifetime of a battery used to power a radio, pager, cellular telephone, or similar device. The battery is attached to a first circuit element to obtain a history of the battery voltage which is used to determine the differential battery voltage. The battery is also attached to a second circuit element which measures the voltage margin between the battery voltage and a reference voltage representing the battery end-of-life condition. A third circuit element divides the voltage margin output of the second circuit element by the differential battery voltage output of the first circuit element to estimate the time that will elapse until the battery voltage approximately equals the reference end-of-life voltage level. This time estimate is used as a basis for performing a variety of functions, including a trigger for a battery shut-off switch to protect radio circuits, and as an activator of indicators to warn the battery user of approaching battery safety thresholds. A method of estimating the remaining useful life of the battery is also disclosed.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.