Method and apparatus for monitoring batttery capacity with charge control
US5440221A · kind A · utility
Assignee
Inventors
Key dates
| Filing date | Jul 8, 1992 |
| Grant date | Aug 8, 1995 |
| Priority date | — |
| Expiry date | Jul 8, 2012 |
Classification
- Technology area (CPC Y)Emerging Cross-Sectional Technologies
- CPC primaryY02E60/10
- WIPO fieldElectrical machinery, apparatus, energy
- WIPO sectorElectrical engineering
Abstract
A battery detect circuit (32) is connected to the battery with the current input to the battery and extracted from the battery measured with a sense resistor (50) and then converted to charge and discharge pulses with a V/F converter (52). A microcontroller (64) is operable to increment a Nominal Available Charge (NAC) register (180) during a charge operation, and to increment a Discharge Count Register (DCR) (184) during a discharge operation. The NAC register (180) indicates the available charge, which value is output to a display (34). The maximum value to which the NAC value can rise is limited by a value stored in the last measured discharge register (182). This value represents the value stored in the DCR (184) whenever the battery is discharged from an apparent full state to a fully discharged state. This results in a qualified transfer to the LMD register (182) such that no knowledge of the actual battery charge is necessary. The charge rate is varied as both a function of temperature, voltage and also of the state of charge. A fast charge rate is initiated when the charge state is above a predetermined low voltage threshold and less than full. When the charge state reaches…
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.