Current driver for an array of LED diodes

摘要

An array of LED diodes includes N channels each having LEDs coupled in series with a switch. A current driver for the array includes a processing circuit configured to detect N currents flowing respectively through the N channels of the array. The detected currents are converted by a single analog to digital converter, one at a time, into a digital word. The circuit further includes N comparator devices configured to control the N switches as result of a comparison between the digital words and respective target digital words. A memory is provided for storing the digital words received from the analog to digital converter.

主权项

1. A current driver device for an array of LED diodes, the array including N channels each one comprising a plurality of LED diodes and a switch arranged in the electric path between the plurality of LED diodes and a common voltage reference, the current driver comprising:
a processing circuit configured to detect N currents flowing respectively through the N channels of said array of LED diodes and convert each detected current into a digital word, N comparator devices configured to control said N switches as result of a comparison between said digital words and respective target digital words, wherein said processing circuit comprises one analog to digital converter configured to convert one at a time the N detected currents into said digital words, and wherein said processing circuit further comprises a memory configured to store said digital words received from the analog to digital converter; wherein each of said comparator devices comprises:
a first counter, anda comparator configured to compare one digital word stored in the memory and the respective target digital word, said comparator configured to set an up counting or a down counting process of the first counter if respectively the digital word is lesser or greater than the respective target digital word and to stop the counting process of the first counter if the digital word is equal to the respective target digital word, the output digital signal of the second counter controlling the respective switch of the respective channel of the array for increasing or decreasing the channel current value respectively if the digital word is lesser or greater than the target digital word.