Circuit and method for battery charge control
US5818201A · kind A · utility
Assignee
Inventors
Key dates
| Filing date | Mar 11, 1997 |
| Grant date | Oct 6, 1998 |
| Priority date | — |
| Expiry date | Mar 11, 2017 |
Classification
- Technology area (CPC H)Electricity
- CPC primaryH02J7/007182
- WIPO fieldElectrical machinery, apparatus, energy
- WIPO sectorElectrical engineering
Abstract
A battery charge control circuit (10) senses the charge condition of cells in a battery pack (12, 14, 16, 18) using a measurement circuit (51). Upon detection of a single under-voltage cell, the charge control circuit is placed in a sleep mode. Pack sense circuit (240) senses when the battery pack is placed in a charger. If circuit (10) was in a sleep mode, it is awakened. If any cell is measured over-voltage, the status is checked versus the other cells. If all the cells are over-voltage, the battery is considered balanced. If one or more cells are not over-voltage, a control circuit (32) activates a discharge transistor (212, 214, 216, 218), discharging the cell within a hysteresis voltage below the over-voltage limit. Charge balancing of cells is continued until the cells are within a programmable hysteresis voltage of each other.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.