Control circuit for a solar-powered rechargeable power source and load
US5221891A · kind A · utility
Assignee
Inventors
Key dates
| Filing date | Jan 31, 1992 |
| Grant date | Jun 22, 1993 |
| Priority date | — |
| Expiry date | Jan 31, 2012 |
Classification
- Technology area (CPC Y)Emerging Cross-Sectional Technologies
- CPC primaryY10S323/906
- WIPO fieldElectrical machinery, apparatus, energy
- WIPO sectorElectrical engineering
Abstract
An inexpensive circuit for controlling the recharging of a rechargeable power source by a photovoltaic panel is used for powering a load such as the lamp of a walk light. Using a minimum number of components, the circuit can charge a rechargeable battery anytime sunlight is sufficient to place a potential across the battery that is greater than the present potential of the battery, can sense a decrease in voltage across the photovoltaic panel with diminishing ambient light and energize the load, can prevent the load from being energized when the ambient light level is sufficient to re-charge the battery, can provide positive feedback at turn-on of the load, thereby hastening turn-on and providing hysteresis, can provide for adjusting the hysteresis bands, can shift the turn-on and turn-off thresholds, and can provide an adequate current to guarantee turn-on when using low leakage solar panels. A further embodiment can additionally exhibit hysteresis at load turn-off so that the load does not cycle on and off and can further raise the load turn-off threshold above the level where the battery is substantially discharged, thereby hastening recharging of the battery. A still further em…
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.