Hysteresis type battery charger having output short circuit protection
US4386308A · kind A · utility
Assignee
Inventors
Key dates
| Filing date | Mar 31, 1981 |
| Grant date | May 31, 1983 |
| Priority date | — |
| Expiry date | Mar 31, 2001 |
Classification
- Technology area (CPC Y)Emerging Cross-Sectional Technologies
- CPC primaryY10S320/21
- WIPO fieldElectrical machinery, apparatus, energy
- WIPO sectorElectrical engineering
Abstract
A hysteresis type battery charger includes a circuit for monitoring battery voltage and in response controlling a pass transistor to supply charging current to a battery. When the battery voltage is below a first predetermined value, high charging rate current is supplied to the battery; when the battery voltage is above a second predetermined value, the battery is supplied with trickle charging current. First and second light emitting diodes (LEDs) are selectively energized to indicate whether the battery is receiving high charging rate current or trickle charging current. The second LED is connected in circuit with the pass transistor to provide charging current foldback during excessive current demand, e.g., short circuit. The battery charger includes a low battery monitor that is energized when the expected battery lifetime is at a predetermined value, e.g., one hour. Temperature compensating networks, are provided whereby battery charging and low battery monitor operating characteristics are substantially temperature independent.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.