Lighting control system having a trim circuit
First Claim
Patent Images
1. A lighting control system for a lighting device, the system comprising:
- a primary controller;
a plurality of drive controllers electrically connected with the primary controller;
a plurality of drive outputs electrically connected with a drive controller, each drive controller controlling at least one drive output;
a plurality of LED modules, each LED module electrically connected with a drive output and having a plurality of series-connected LEDs, wherein at least one of said plurality of LED modules include;
a trim circuit to compensate for forward voltage variations among said LEDs of the LED module, said trim circuit balancing voltage drop differences across the series-connected LEDs thereby providing substantially uniform lighting for said plurality of LED modules, wherein said trim circuit includes;
a transistor that effectively nullifies the forward voltage variations among said LEDs of the LED module by adjustment of gate voltage of the transistor, said gate voltage of the transistor generated based on the difference between positive input from the transistor drain and a negative input.
0 Assignments
0 Petitions
Accused Products
Abstract
A lighting control system suitable for a surgical lighting device. The lighting control system includes circuitry that compensates for the effects of temperature changes in a lighting device, and that compensates for forward voltage variations among LED lighting modules to provide substantially uniform light output.
59 Citations
8 Claims
-
1. A lighting control system for a lighting device, the system comprising:
-
a primary controller; a plurality of drive controllers electrically connected with the primary controller; a plurality of drive outputs electrically connected with a drive controller, each drive controller controlling at least one drive output; a plurality of LED modules, each LED module electrically connected with a drive output and having a plurality of series-connected LEDs, wherein at least one of said plurality of LED modules include; a trim circuit to compensate for forward voltage variations among said LEDs of the LED module, said trim circuit balancing voltage drop differences across the series-connected LEDs thereby providing substantially uniform lighting for said plurality of LED modules, wherein said trim circuit includes; a transistor that effectively nullifies the forward voltage variations among said LEDs of the LED module by adjustment of gate voltage of the transistor, said gate voltage of the transistor generated based on the difference between positive input from the transistor drain and a negative input. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8)
-
Specification