Full-charge indicator for battery chargers
US4394613A · kind A · utility
Assignee
Inventor
Key dates
| Filing date | Jan 19, 1981 |
| Grant date | Jul 19, 1983 |
| Priority date | — |
| Expiry date | Jan 19, 2001 |
Classification
- Technology area (CPC Y)Emerging Cross-Sectional Technologies
- CPC primaryY10S323/902
- WIPO fieldElectrical machinery, apparatus, energy
- WIPO sectorElectrical engineering
Abstract
A full-charge indicator for battery chargers, includes a transistor which is in a conductive state as long as charging current to the battery is not less than a level which indicates that the battery did not reach full charge. When the battery reaches full charge, a voltage drop in a resistor in the charging current path is not sufficient to maintain the transistor in a conducting state, and therefore it is switched off. When this occurs an LED is turned on, to indicate a full charge state of the battery. A photocoupler together with a photocoupler transistor are included. When the transistor is off, the photocoupler activates the photocoupler transistor to shunt out a resistor, thereby reducing the charging current to the battery to a float charging current and prevent the battery from being overcharged and damaged.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.