Non-linear light-emitting load current control
US6285139A · kind A · utility
Assignee
Inventor
Key dates
| Filing date | Dec 23, 1999 |
| Grant date | Sep 4, 2001 |
| Priority date | — |
| Expiry date | Dec 23, 2019 |
Classification
- Technology area (CPC H)Electricity
- CPC primaryH05B45/385
- WIPO fieldElectrical machinery, apparatus, energy
- WIPO sectorElectrical engineering
Abstract
A sensor circuit detects a current supplied to a set of light-emitting diodes and produces a current reading dependent on the temperature of operation of these light-emitting diodes. The sensor circuit comprises first and second serially interconnected resistors also connected in series with the set of light-emitting diodes. The sensor circuit also comprises a temperature-dependent impedance connected in parallel with one of the first and second resistors. At least a portion of the current through the set of light-emitting diodes flows through the sensor circuit to enable the first and second serially interconnected resistors and the temperature-dependent impedance to produce a variable voltage signal representative of the current through the set of light-emitting diodes, this variable voltage signal being dependent upon temperature. The above sensor circuit finds application in a substantially constant intensity light source.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.