Patent ID: 9198242
Filing Date: 2015-11-24
Classification: H05B

Abstract:
1. An apparatus for driving a plurality of LEDs, comprising: a plurality of LEDs divided into a plurality of LED segments connected in series, each of said plurality LED segments having a positive end and a negative end, and a switching device connected in parallel between the positive and negative ends; an input voltage connected to the positive end of a leading LED segment of said plurality of LED segments; a switching voltage detector having a first end connected to the negative end of a trailing LED segment of said plurality of LED segments, and generating a first mode change signal when said input voltage increases and a second mode change signal when said input voltage decreases; a current limiting device having a first end connected to a second end of said switching voltage detector and a second end connected to ground; and a switch controller receiving said input voltage and said first and second mode change signals and generating a plurality of switching control signals for respectively controlling the switching devices of said plurality of LED segments; wherein said switching voltage detector includes a delta voltage detector, said delta voltage detector comprising: