Positive buck /boost type LED constant current driver circuit

Published:2011/7/20 6:51:00 Author:Fiona | Keyword: buck /boost, constant current, driver | From:SeekIC

working principleThe input circuit consists of the fusible resistor R1,VD1,VD2,C1,CZ and filter inductor u;power adjustment circuit consists of LNK3OGP,energy storage inductor L2,VD3,R2,C4 and C5.When LNK306 turns on, the input current I constitutes a loop through (LNK306) D → (LNK306) S → L2 → C2 (-) and stores the input current IIN in inductor L2 (the inductor current linear increases by UI / LI),the polarity is that up is positive and under is negative;when LNK306 is off,it can't be mutated because of the inductor current(inductor current decreases linearly by UI/L1),the polarity is that up is negative and under is positive;the energy stored in L2 constitutes a loop through by the lower end of L2(ground) →LED (load) →VD3 →R2 →the upper end of L2.



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