1 l c 410591 c h a r g e p u m p w h i t e le d su p p ly g e n e r a l d e s c r i p t i on t h e l c 4105 9 1 i s a w h it e l e d s up p l y t h a t p r o v i d es f ou r r e g u l a t e d c u rr e n t s ou r ces w it h a f r ac ti on a l c h a r g e pu m p dc - d c c on v e r t e r . i t acce p t s a n i n pu t v o lt a g e r a n g e f r o m 2 . 7 v t o 5 . 5 v a nd m a i n t a i n s a c o n s t a n t c u rr e n t . a n e x t e r n a l se n se r es i s t o r d e t e r m i n es 100 % f u ll sca l e l e d c u rr e n t. t h e l c 4105 9 1 d e li v e rs u p t o 1 05 m a o f l o a d c u rr e n t t o d r i ve on e , t w o , t h r ee , o r f ou r w h i t e l e ds . w h e n it d r i v es f ou r l e d s , m a x i m u m 2 6 m a o f e ac h l e d i s a v a il a b l e . w h e n it d r i v es t h r ee l e d s , m a x i m u m 35 m a o f eac h l e d i s a v a il a b l e . i t op e r a t es w it h 6 00 k h z f i x ed - f r e qu e n c y s w it c h i n g w it hou t i n du c t o r s , t h e r e f o r e t h e e m i n o i se i s v e r y l i m it e d . b y pu l s i n g t h e br g t i npu t , t h e l e d b r i g h t n ess ca n b e c on t r o ll e d i n m u lti p l e s t e p s do w n t o 5 %. o n ce t h e d es i r e d b r i g h t n ess i s se t , l c 4 1 0 5 91 m a i n t a i n s t h e b r i g h t n ess as l o n g as t h e br g t i np u t k ee p s h i g h . i f a n br g t i npu t i s k e p t l o w f o r m o r e t h a n 2 m s , it e n t e r s s hu t d o w n m od e. t h e l c 410 5 91 i s a v a il a b l e i n a f l ga ( wl - c s p ) , v q f n p ac k a g es. t yp i c a l a p p l i c a t i o n c i r c u it f e a t u r es ? low noise, high efficiency cmos charge pump b u ilt - i n c o n s t a n t c u rr e n t c i r c u i t 2 . 7 v t o 5 . 5 v i n p u t v o l t a g e d r i v es on e , t w o , t h r ee o r f ou r w h it e l e d s w it h m a x i m u m t o t a l c u rr e n t 1 05 m a s e lf - c h a n g i n g o f c h a r g e p u m p m od e ( p ass m od e a nd 1 . 5 b o o s t m od e) t y p i ca l + - 1 . 5 % c u rr e n t m a t c h i ng o f a n y t w o l e d ou t pu t s s o f t s t a r t li m it s i n r u s h c u rr e n t c h a r g e pu m p f r e qu e n c y 600 k h z 5 % t o 1 0 0 % b r i g h t n ess c on t r o l t h r o u gh s i n g le - w i r e s e r i a l i nput m a x i m u m 1u a s hu t d o w n c u rr e nt a p p l i c at i o ns w h it e l e d d i s p l a y b a c k li g h ts w h it e l e d k e y p a d b ac k li g h ts 1 - c e ll li - i on b a tt e ry - op e r a t e d e qu i p m e n t i n c l u d i ng p d a s , h a nd - h e l d p c s , ce ll u l a r p h on es f l a t p a n e l d i s p l a ys 20 0 4 . 09 . 07 ? ? ? ? ? ? ? ? ? ? ? ? ?
2 p i n a ss i g n m e nt b l o c k d i a g r am p i n n a me f un c t i on v in p o w e r s up p l y i npu t . b y p ass v i n t o g nd w it h a 2 . 2 u f cap ac it o r . c 1a f l y i n g c a p ac it or ( 1 ) + c 1b f l y i n g c a p ac it or ( 1 ) - c 2a f l y i n g c a p ac it or ( 2 ) + c 2b f l y i n g c a p ac it or ( 2 ) - br gt b r i g h t n ess c on t r o l i n p u t . t h e f i r s t ti m e , b r g t m u s t b e pu l se d f o r r ese t . t h e sec ond ti m e it g o es h i g h ( 1 2 0 u s m i n ) , t h e n t h e l e d s t u r n on a t a 1 0 0 % b r i g h t n ess . p u l s i n g br g t l o w c on t r o l s t h e l e d c u rr e n t i n m u lti p l e s t e p s . i f br g t i s k e p t l o w f o r m o r e t h a n 2 m s , t h e l c 410 5 91 e n t e r s s hu t do w n m od e a nd l e d s t u r n o f f . p l ease see b r i g h t n ess c on t r ol c h a p t e r . i set e x t e r n a l r es i s t o r . m a x i mu m l e d c u rr e n t i s d e t e r m i n e d b y i l ed ( m a ) = 48 /r s et (k ? ) v r ef v r e f o u t p u t ( t y p i ca l l y 1 . 2 v ) . b y p a s s v r ef t o g nd w it h a 3 0 p f ca p ac it o r . v r e f o u t pu t m u s t b e k e p t h i gh - i m p e d a n ce. g nd p o w e r s up p l y g r ound . c h a r g e pu m p s w it c h i n g c u rr e n t f l o w s t h r o ug h t h i s p i n . l e d _ i n 1 ~4 c onn ec t a l e d b e t w ee n v ou t a nd l e d _ i n 1 ~ 4. v cp c h a r g e p u m p o u t p u t . b y p ass v c p t o g nd w it h a 2 . 2 u f ca p ac it o r . t est n o t u se . m u s t b e o p e n .
3 n o t e 1: s p ec i f i ca ti on s t o - 40 c a r e g u a r a n t ee d b y d es i g n a nd no t p r o d u c ti o n t es t e d. p a r a m e t er c o n d i t i o ns m in t yp m ax u n it s u p p l y v o lt a g e (v in ) 2 .7 5 .5 v m a x i m u m o u t pu t c u rr e nt t a = 25 c 105 ma t a = 25 c , 4 l e ds 26 ma ma x i m u m l e d c u rr e nt ( p e r on e l e d) t a = 25 c , 3 l e ds 35 ma v in = 4 . 1 t o 5 . 5v ( w h e n p ass m od e) 2 ma n o l o a d s up p l y c u rr e nt ( a t i l ed 1 0 0 % se tti n g) v in = 2 . 7 t o 4 . 1v ( w h e n 1 . 5 b oo s t m od e) 5 ma c h a r g e p u m p f r e qu e n cy 600k hz i n p u t c h a r g e p u m p m od e t h r es ho ld p ass m od e t o 1 . 5 b oo s t m ode 4 .1 v i n p u t c h a r g e p u m p m od e h y s t e r y s is 0 .5 v v r e f o u t pu t v o lt a ge 1 .2 v i se t b i as v o lt a ge 1 .2 v l e d c u rr e n t a cc u r a cy + - 3 % l e d t o l e d c u rr e n t m a t c h i ng + - 1 .5 % s hu t do w n s u p pl y c u rr e nt v in = 2 . 7 t o 5 . 5 v , t a = 25 c 1 ua br g t s e t l o w t i m e ( t l o) 0 .5 500 us 0 .5 us m i n i m u m b r g t s e t hi g h t i m e ( t h i) o n l y w h e n w a k i n g up f r o m s hu t d o w n m od e (i n iti a l th i) 150 us br g t s hu t do w n ti m e ou t ( t s t dn) 2 ms v in = 4 .5 t o 5 . 5v 3 v br g t t h r es ho l d hi gh v in = 2 . 7 t o 4 . 5v 2 .5 v br g t t h r es ho l d l ow v in = 2 . 7 t o 5 . 5v 0 .5 v br g t i npu t c u rr e nt v in = 2 . 7 t o 5 . 5 v , t a = 25 c 1 ua a b s o l u t e m ax i m u m r a t i n gs m a x i m u m s up p l y v o lt a g e ( v dd ) = - 0 . 3 v ~ 7 . 2 v , m a x i m u m s upp l y v o lt a g e ( v ss ) = - 0 . 3 v ~ 0 . 3v s t o r a g e t e m p e r a t u r e - 55 c ~ 1 25 c e l e c t r i c a l c h a r a c t e r i s t i cs s u p p l y v o lt a g e (v in ) = 3 . 6 v , r s et = 3 . 2k ? ?? l e d f o r w a r d v o lt a g e (v f ) = 3 . 2 v , b y p ass ca p ac it o r(c in ) = 2 . 2 u f , o u t pu t c a p ac it o r(c cp ) = 2 . 2u f , f l y i n g c a p ac it o r s ( c 1 , c 2 ) = 1 uf t a = - 40 c ~ 85 c ( no t e1 ) ( u n l ess s p ec i f i e d , t y p i ca l v a l u es a r e a t t a = 25 c )
4 t y p i c a l c h a r a c t e r i st i cs l e d c u rr e n t v s . s u p p l y v o lt a ge (v f = 3 . 2 v , 3 . 4 v) v f = 3 . 4v v f = 3 . 2v 0 .0 5 .0 10 .0 15 .0 20 .0 3 .0 3 .5 4 .0 4 .5 5 .0 s u p p l y v o l t a g e ( v) iled(m a) l e d cur r e n t v s . s u p p l y v o l t a ge (t a = 25 oc , 60 oc ) 0 .0 5 .0 10 .0 15 .0 20 .0 3 .0 3 .5 4 .0 4 .5 5 .0 s u pp l y v o l t a g e ( v) iled(m a) 25oc 60oc l e d e f f i c i e n c y v s . s u p p l y v o l t a ge (v f = 3 . 2 v , 3 . 4 v , 3 . 6 v) v f = 3 . 4v v f = 3 . 2v v f = 3 . 6v 0 20 40 60 80 1 00 3 .0 3 .5 4 .0 4 .5 5 .0 s u p p l y v o l t a g e ( v) led efficie ncy( %) l e d e f f i c i e n c y v s . s u p p l y v o l t a ge (t a = 25 oc , 60 oc ) 0 20 40 60 80 1 00 3 .0 3 .5 4 .0 4 .5 5 .0 s u p p l y v o l t a g e ( v) led efficiency( %) 25oc 60oc s u p p l y cu r r e n t v s . s u p p l y v o l t a ge (v f = 3 . 2 v , 3 . 4 v , 3 . 6 v) v f = 3.2v v f = 3 . 4v v f = 3 . 6v 0 20 40 60 80 100 120 3 .0 3 .5 4 .0 4 .5 5 .0 s u p p l y v o l t a g e ( v) supply current(ma) s u p p l y c urr e n t v s . s u p p l y v o l t a ge (t a = 25 oc , 60 oc ) 0 20 40 60 80 100 120 3 .0 3 .5 4 .0 4 .5 5 .0 s u p p l y v o l t a g e ( v) supply current(ma) 25oc 60oc c h a r g e p u m p e f f i c i e n c y v s . s u p p l y v o l t a ge ( l o a d c u rr e n t 60 m a . n o l e d i s c o n n e c t e d) 0 20 40 60 80 1 00 3 .0 3 .5 4 .0 4 .5 5 .0 s u p p l y v o l t a g e ( v) ch arge pu mp efficiency(%) 25oc 60oc r e f e r e n c e v o l t a g e v s . s u p p l y v o l t a ge ( l o a d c u rr e n t 60 m a) 1 . 10 1 . 15 1 . 20 1 . 25 1 . 30 3 .0 3 .5 4 .0 4 .5 5 .0 s u p p l y v o l t a g e ( v) vref( v) 25oc 60oc u n l ess o t h e r w i se s p ec i f i e d ; s u p p l y v o lt a g e (v in ) = 3 . 6 v , r s et = 3 . 2kw , led forward voltage(v f )=3.2v, t a =25oc, drive 4 leds b y p ass ca p ac it o r(c in ) = 2 . 2 u f , o u t pu t c a p ac it o r(c cp ) = 2 . 2u f , f l y i n g c a p ac it o r s ( c 1 , c 2 ) = 1 uf
5 t y p i c a l c h a r a c t e r i s ti cs u n l ess o t h e r w i se s p ec i f i e d ; s u p p l y v o lt a g e (v in ) = 3 . 6 v , r s et = 3 . 2kw , led forward voltage(v f )=3.2v, t a =25oc, drive 4 leds b y p ass ca p ac it o r(c in ) = 2 . 2 u f , o u t pu t c a p ac it o r(c cp ) = 2 . 2u f , f l y i n g c a p ac it o r s ( c 1 , c 2 ) = 1 uf s u p p l y c u rr e n t v s . s u p p l y v o lt a ge ( n o l o a d c u rr e n t) 0 2 4 6 8 10 2 .5 3 .0 3 .5 4 .0 4 .5 5 .0 5 .5 s u p p l y v o lt a g e ( v) supply current(ma) 25oc 60oc s hu t d o w n curr e n t v s . s u p p l y v o lt a ge (t a = 25 oc , 60 oc ) 0 .0 0 .5 1 .0 1 .5 2 .0 2 .5 3 .0 3 .5 4 .0 4 .5 5 .0 5 .5 s u p p l y v o lt a g e ( v) s hutdown current(ua) 25oc 60oc l e d curr e n t v s . t a r g e t l e d curr e n t% (t a = 25 oc , 60 oc ) 0 .0 5 .0 1 0 .0 1 5 .0 2 0 .0 2 5 .0 3 0 .0 0% 2 0% 4 0% 6 0% 8 0% 1 0 0% 1 2 0% t a r g e t i l ed % led current(ma) 25oc 60oc l e d cu r r e n t v s . t a r g e t l e d curr e n t% (r set = 3 . 2k w , 2.5k w , 2. 0k w ) r set = 2.5k w r s et = 3 . 2k w r set = 2.0k w 0 .0 5 .0 10 .0 15 .0 20 .0 25 .0 30 .0 0% 20% 40% 6 0% 8 0% 1 00% 1 20% t a r g e t i l ed % led current(ma) l e d curr e n t v s . s u pp l y v o lt a ge (r set = 3.2k w , 2.5k w ) r set = 3.2k w r set = 2.5k w 0 .0 5 .0 1 0 .0 1 5 .0 2 0 .0 2 5 .0 3 0 .0 3 .0 3 .5 4 .0 4 .5 5 .0 s u pp l y v o l t a g e ( v) iled(m a) l e d c urr e n t v s . d i o d e v o lt a ge (v in = 3 . 2 v , 3 . 4 v , 3 . 6 v) v in = 3 . 2v v in = 3 . 4v v in = 3 . 6v 1 0 .0 1 1 .0 1 2 .0 1 3 .0 1 4 .0 1 5 .0 1 6 .0 1 7 .0 1 8 .0 3 .0 3 .1 3 .2 3 .3 3 .4 3 .5 3 .6 d i o d e v o lt a g e ( v) led current(ma) l e d e f f i c i e nc y v s . l e d cu r r e nt ( l e d c u rr e n t i s v a r i e d b y 1 - l i n e d i m m i n g , n o l e d is c o n n e c t e d , v in = 3 . 2 v , 3 . 6 v , 4 . 2 v) v in = 3 . 6v v in = 3 . 2v v in = 4 . 2v 0 20 40 60 80 1 00 0 5 10 15 20 l e d curr e n t ( m a) l ed e fficie ncy( %) s u pp l y v o l t a g e v s . o u t p u t v o l t a ge ( load current 60ma) 0 .0 2 .0 4 .0 6 .0 3 .0 3 .5 4 .0 4 .5 5 .0 s u p p l y v o l t a g e ( v) output voltage(v)
6 o p e r a ti on c i r c u i t d e s c r i p t i on t h e l c 4105 9 1 i s a w h it e l e d s upp l y w h i c h acce p t s t h e i n pu t v o lt a g e f r o m t h e li - i on b a tt e r y . w h il e t h e li - i on b a tt e r y h as t h e ou t pu t v o l t a g e r a ng e f r o m 2 . 7 t o 5 . 5 v , t h e f o r w a r d v o lt a g e (v f ) o f t h e w h it e l e d i s a bou t 3 . 6 v t y p i ca l l y . s o w h e n t h e b a tt e r y d e g r a d es t h e ou t pu t vo lt a g e t o a b o u t 3 . 6 v , t h e h i g h e r v o lt a g e m u s t b e g e n e r a t e d i n t e r n a ll y . t h e l c 41 0 5 9 1 e m p l o y s a c h a r g e pu m p t o s t e p up t h e o u t p u t v o lt a g e t o 1 . 5 ti m e s t h e i n p u t v o lta g e . t h i s c h a r g e pu m p se l ec t s t h e op ti m u m boo s t m od e , a nd c h a n g es t h e b o o s t m od e a u t o m a ti ca l l y . l e d c u rr e n t ( i l ed ) i s d e t e r m i n e d b y t h e br g t i npu t v o lt a g e a nd t h e r es i s t a n ce o f a n i n t e r n a l s t a n d a r d v o lt a g e g e n e r a ti on s o u r ce ( v ref= . 1.2 ) is forced on the e x t e r n a l r es i s t o r w it h h i g h acc u r a cy b y a n i n t e r n a l op - a m p , s o t h e c u rr e n t p ass i n g t h r ou g h t h e e x t e r n a l r es i s t o r ( i r s et ) w ill b e i r s et = v r ef / r s et . l c 41 0 5 91 i n c l ud es t h e c u r r e n t r e g u l a t o r t o d e li v e r t h e r e g u l a t e d c u rr e n t t o th e l e d s , w h i ch a r e c o m po se d o f c u rr e n t m i rr o r s w it h a 40 t o 1 r a t i o . f o r e x a m p l e , w h e n v r ef = 1 . 2 v , r s et = 2k ? , t h e n i r s et = 0 . 6 m a , a nd i l ed = i r s et x 40 = 24 m a . i f f ou r l e d s a r e a tt ac h e d , t h e d e v i ce d r i v e up a t o t a l o f 24 m a x 4 = 96 m a t h r ou g h t h e l e d s . t h i s t e r m do es n o t i n c l ud e t h e t o l e r a n ce o f t h e e x t e r n a l r es i s t e r r s et . i f p r ec i s i on l e d c u rr e n t acc u r a c y i s r e qu i r e d , a p r ec i s i on r es i s t e r i s n ee d e d ( e x . 1 % t o l e r a n ce r es i s t e r) . t h e l e d b r i g h t n ess ca n b e c on t r o ll e d b y se r i a l s i g n a l i n p ut . s hu t d o wn m o de br g t i npu t i s k e p t l o w f o r m o r e t h a n 2 m s , it e n t e r s s hu t d o wn m od e , a nd r e du ce t h e qu i esce n t c u rr e n t t o 1 a m a x i m u m. s o f t s t a rt l c 410 5 91 r e qu i r es a p u l se ( > 2 0 n s ) a nd a l o w i n p u t m o r e t h a n 2 m s t o w a k e up f r o m t h e s hu t do w n m od e . t h e n , i f a h i g h i n pu t ( > 1 2 0u s ) i s s up p li e d on br g t , l c 410 5 91 s t a r t s w it h 1 0 0 % l e d c u rr e n t m od e w it h s o f t s t a r t m od e t o r e du ce t h e i n r u sh c u rr e nt . i n r u s h c u rr e n t w ill b e g e n e r a t e d w h e n t h e c h a r g e pu m p op e r a t es w it h f l y i n g ca p ac it o r s d i sc h a r g e d . w h e n t h e ca p ac it o r s a r e b e i n g c h ar g e d w it h l o w i m p e d a n ce , e x c e ss c u rr e n t m a y s u r g e i n t o t h e ca p ac it o r s f r o m t h e b a tt e r y . s o f t s t a rt i s don e t o r e d u ce s t r ess on t h e b a tt e r y a nd e x t e r n a l c o m pon e n t s. d u r i n g s o f t s t a r t , t h e s w it c h r es i s t a n ces l i m it t h e i n r u s h c u rr e n t u se d t o c h a r g e t h e f l y i n g a nd ou t put ca p ac it o r s. b r i g h t n e ss c o n t r ol u se b r g t i npu t s as a se r i a l s i g n a l t o c o n t r o l t e n l e v e l s o f l e d b r i g h t n ess b y a d j u s ti n g t h e a m oun t o f l e d c u rr e nt . i f t h e l o w l e v e l i npu t c on ti nu es m o r e t h a n 2 m s , it w ill g o i n t o t h e s hu t do w n m od e. l c 410 5 91 r e qu i r es a p u l se ( > 2 0 n s ) a nd a l o w i n p u t m o r e t h a n 2 m s t o w a k e up f r o m t h e s hu t do w n m od e . t h e n , i f a h i g h i n pu t ( > 1 2 0u s ) i s s upp l i e d on br g t , l c 410 5 91 s t a r t s w it h 1 0 0 % l e d c u rr e n t m od e . b r i g h t n ess c on t r o l i s d o n e b y pu l s i n g br g t l o w ( 500n s t o 5 0 0 u s p u l se w i d t h ). e ac h p u l s e r e du ces t h e l e d c u rr e n t . t h e 10 th p u l se r e du ces t h e c u rr e n t b y 5 % , a nd t h e 11 th pu l se se t s t h e l e d c u rr e n t b ac k t o 1 00 % . d r i v e br g t l o w m o r e t h a n 2 m s t o pu t t h e l c 41 0 5 9 1 i n s hu t d o w n m od e . b e l o w f i g u r e s ho w s a t i m i n g d i a g r a m . c a p a c i t o r s e l ec t i on f o r t h e i n pu t b y p ass ca p ac it o r , t h e ou t put ca p ac i t o r a n d t h e c h a r g e pu m p f l y i n g c a p ac it o r s, w e r ec o mm e nd t o u se t h e ca p ac it o r s w h i c h h a v e l o w e qu i v a l e n t se r i es r es i s t a n ce ( es r ) , a nd l o w v a r i a ti on o v e r t e m p e r a t u r e , s u c h as x 5 r o r x 7 r o f t h e ce r a m i c cap ac it o r s. initial thi >150us(min) 1 2 3 4 5 6 7 8 9 10 11 12 tstdn=2ms(typ) tlo=500ns~500us thi>500ns tstdn=2ms(typ) thi>20ns tsoft_start 10 0% 8 0% 70% 6 0% 50% 40% 3 0% 20% 10% 5% 100% 80% shutdown mode shutdown mode <> input a single pulse(thi>20ns), and keep low input more than 2ms to enter the shutdown mode. <> when wake up from the shutdown mode, initial thi needs more than 150us to complete the soft start. .
7 a dd i t i o n a l le d d r i v i ng t h e l c 4105 9 1 ca n d r i v e a d d iti o n a l l e d s b y u s i n g t h e ou t pu t v o lt a g e . t h e e x a m p l e c i r c u it i s b e l o w . n o t e i f t h e t o t a l o u t p u t c u rr e n t i s l a r g e r t h a n 1 0 5 m a , t h e l c 410 5 9 1 m a y no t m ee t t h e s p e c i f i ca ti on . t h e r es i s t e r s a nd t h e s w it c h es s hou l d b e c o n n ec t e d i n se r i a l w it h t h e a dd it i on a l l e d s t o c on t r o l t h e s i n k c u rr e n t a n d t o c on t r o l t h e l e ds on / o f f . b e l o w a pp li ca ti on ca n b e a v a il a b l e a l s o . n o ti ce w h e n a pp l y i n g a bo v e a pp li ca ti o n , t h e c u rr e n t d i f f e r e n ce o f t h e l e d s t h a t s i n k i n t o t h e sa m e l e d _ i n t e r m i n a l , w ou l d no t b e r e g u l a t e d.
8 p a c ka ge 1 . v q f n 16 * t es t p i n m u s t b e op e n . i s et led_in1 led_in2 led_in3 led_in4 t e s t* b r gt v r ef vdd c2b c1a v cp c 2a c 1b v ss
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