Switching device for driving led array by pulse-shaped current modulation

Abstract

A circuit drives an LED array and controls the brightness of the LED array by regulating the current flowing through the array. The LED array is driven by a pulse-shaped current of which the mean value is regulated with at least one or two of the following types of modulation: frequency modulation, pulse-width modulation, and amplitude modulation.

1 . A switching device for driving an LED array, the switching device comprising a drive generator configured to modulate a mean strength of a current provided to the LED array by a first modulation type, a second modulation type, and a third modulation type. 
   
   
       2 . The switching device of  claim 1 , wherein the first modulation type is pulse-width modulation, the second modulation type is amplitude modulation, and the third modulation type is frequency modulation. 
   
   
       3 . The switching device of  claim 1 , wherein the first modulation type is configured to reduce the mean strength from Inom to 0.05 Inom, the second modulation type is configured to reduce the mean strength to less than 0.05 Inom, and the third modulation type is configured to reduce the mean strength to 0.05*10 −3  Inom. 
   
   
       4 . The switching device of  claim 3 , wherein the first modulation type is pulse-width modulation, the second modulation type is amplitude modulation, and the third modulation type is frequency modulation. 
   
   
       5 . A switching device for driving an LED array, wherein the switching device comprises a drive generator configured to provide a current having a mean strength which is reducible from Inom to 0.05*10 −3  Inom using three different types of modulation. 
   
   
       6 . The switching device of  claim 5 , wherein the three different types of modulation include pulse-width modulation, amplitude modulation, and frequency modulation. 
   
   
       7 . The switching device of  claim 6 , wherein the pulse-width modulation is configured to reduce the mean strength from Inom to 0.05 Inom, the amplitude modulation is configured to reduce the mean strength to less than 0.05 Inom, and the frequency modulation is configured to reduce the mean strength to 0.05*10 −3  Inom.