high efficiency step down led driver gen e ral description SM8200 fea t ures wide inp u t op erati ng v o lta ge ra nge from 8 v to 48 v low c u rrent sen s e th resh old of 30 0mv power ef fici ency up to 9 4 % appl ica t ion from a few ma to more than 1a ou tput led stri ng fro m on e to h und reds exc e lle nce co ntrol sc heme (crm ) led sh ort-circ uit p r otec tion (scp) led ope n-vo ltag e prot ecti on (o vp) ju ncti on o v er-te m pera t ure s hutd o wn pro t ecti on cycl e-by-c yc le c u rrent l i mi t provi d ing sot-23 6-le ad pa cka g e mr16 high power l e d d r ive r s sig nag e an d de corat i ve led ligh t ing auto moti ve or ind u stri al appl ic ations typical applicat ion cir cuit www.s amh op.c o m.tw 1 re v. 1. 0 @ 20 11/1 2 the sm820 0 is a hi gh e ffic i enc y s t ep -d own led driv er, it has v e ry wide in put vo ltag e ra nge from 8 v to 48 v, the d e vi ce i s de sig ned t o ope rate i n crit ica l co nduc tion mod e (crm) c ontrol sc hem e (thi s o perati ng mode resu lts in an av erag e l e d curren t whi c h is eq ual to hal f of the p eak s w i t chi ng cu rre n t) opti m iz ed to driv e high cu rre n t leds. thu s hig h ly e ffic i ent a nd ac cura te led cu rre n t re gul atio n can be a c hi eve d . in crm, the switc h in g freq uenc y wil l v a ry with lin e, lo ad , ind u ct ance and swit chin g l o ss , th e c u rrent of the ind u cto r sta r ts a t ze ro e a ch swit chin g cyc le. so, ex ternal p o wer mo sfet ca n sig n ifi c an tly be re duc ed the peak spi k e vo ltag e. a ex ternal sen s e re sis t or (r sn ) set s the pea k in duc tor cu rre n t, wh ich is re gula t ed at 30 0mv (typi c all y ), und er thi s op eratin g mo de re sul t s i n an ave r age curren t which is equa l to hal f of th e pe ak switch ing curren t. q1 c in zc d ga te cs ct gnd vi n r sn l1 co ut d1 c1 sm8 200 the sm820 0 o ffers the foll owing prote c tio n fu ncti ons : led open prote c tio n , led sho r t-circ uit pro t ecti on a nd ic jun c tio n ov er-tem peratu r e sh utdo wn wi th au to rec o ve ry fea t ure. the dev ice is av aila ble in the lo w profi l e 6 - lead sot-23 p a ck age an d is ide a l for spa c e co nstra i ned app lic atio ns. 8v dc 48 vd c preliminar y datasheet
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