Abstract: A fault detecting circuit in a string of LEDs D1-Dc containing comparing operational amplifiers IC1/IC2 connected to a current source is divided into sections, D1-Da, D2-Db, and D3-Dc, wherein the common between the Da cathode and the D2 anode is connected to the noninverting-input of IC1, while the common between the Db cathode and the D3 anode is connected to the noninverting-input of IC2, and to the string D1-Db is connected in parallel to a divider comprising R1/R2, while the string comprising D2-Dc is connected in parallel to a divider comprising R3/R4, and the common of R1/R2 is connected to the inverting-input of IC1 and the common of R3/R4 is connected to the inverting-input of IC2, while the outputs of IC1/IC2 are connected to the bases of corresponding transistors T1/T2, whose emitters are connected to ground and collectors are connected to the voltage source and also to the output terminal.

Abstract: A fault detecting circuit in a string of LEDs D1-Dc containing comparing operational amplifiers IC1/IC2 connected to a current source is divided into sections, D1-Da, D2-Db, and D3-Dc, wherein the common between the Da cathode and the D2 anode is connected to the noninverting input of IC1, while the common between the Db cathode and the D3 anode is connected to the noninverting input of IC2, and to the string D1-Db is connected in parallel to a divider comprising R1/R2, while the string comprising D2-Dc is connected in parallel to a divider comprising R3/R4, and the common of R1/R2 is connected to the inverting input of IC1 and the common of R3/R4 is connected to the inverting input of IC2, while the outputs of IC1/IC2 are connected to the bases of corresponding transistors T1/T2, whose emitters are connected to ground and collectors are connected to the voltage source and also to the output terminal.