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1 power management SC614 low noise backlight and flash driver with serial interface united states patent no. 6,504,422 www.semtech.com power management april 28, 2006 features ? four independent current sinks for main backlight, adjustable from 0.4ma to 32ma each ? dedicated mdim pin for pwm dimming of main backlight ? three independent current sinks for sub-backlight or flash, adjustable from 0.4ma to 102ma each ? configurable sub-backlight or flash sinks ? dedicated sdim pin for pwm dimming of sub- backlight ? dedicated fl pin for flash control ? current accuracy to within 1.5% down to 4.8ma ? current matching to within 0.5% down to 4.8ma ? very high efficiency over 90% of battery life ? shutdown current 0.1 a (typ) ? three charge pump operating modes: 1x, 1.5x, and 2x ? i 2 c serial interface ? soft-start/in-rush current limiting ? 1.33mhz and 250khz programmable fixed frequency options ? short-circuit/thermal protection ? output open circuit protection ? mlpq-24 package (4mm x 4mm), fully weee and rohs compliant ? cellular phone backlighting and flash ? lcd modules ? pda backlighting and flash ? rgb led driver the SC614 is a high efficiency charge pump led driver using semtech?s proprietary mahxlife tm technology. performance is optimized for use in li-ion battery applications. each of 7 led currents can be programmed via the i 2 c serial control bus. m1 through m4 are for led backlighting of lcd main displays. s1/fl3 through s3/fl1 can be used for backlighting sub displays and/ or for driving flash leds. these three current sinks are configurable over the i 2 c interface for any combination of pins for sub or flash use. the charge pump automatically selects an operating mode based on the number of active loads, input voltage, and load currents required. any combination of led drivers can be enabled at one time, allowing the SC614 to power any combination of backlight and flash required by the application. two dedicated pins, mdim and sdim, are provided to allow pwm dimming of the main and sub-backlights and one dedicated pin, fl, allows direct control of the flash. all three pins can be utilized without having to use the i 2 c interface once the registers are set up. the enable pin can be used to put the device in low-current shutdown mode drawing 0.1 a (typ), or a reg- ister can be written that sets the device in a sleep mode that reduces the current to 50 a (typ). description d1 led c2 1u 434ma max (500ms) d2 led d3 led d4 led d5 led 32ma max 32ma max 32ma max 32ma max 306ma max. c1 2u2 c3 1u c4 1u vin 11 vin 17 en 2 sda 7 scl 8 asel 5 sdim 3 md i m 4 fl 6 vout 9 vout 16 m1 1 m2 24 m3 23 m4 22 s1/fl3 20 s2/fl2 19 s3/fl1 18 gnd 12 gnd 21 tpad c1+ 10 c1- 13 c2+ 15 c2- 14 u1 SC614 en sda scl sdim fl mdim 328ma max continuous vbat r1 pull-up r2 pull-up vlogic note: r1 and r2 pull-up resistors are a requirement of the i2c specification main backlight flash typical application circuit applications
? 2006 semtech corp. power management SC614 united states patent no. 6,504,422 www.semtech.com 2 absolute maximum ratings electrical characteristics unless specified, t a = 25c for typ, -40c to 85c for min and max, v in = 3.2v to 4.2v, c in = 2.2 f, c out = c pump = 1 f (esr = 0.03 ). r e t e m a r a pl o b m y sm u m i x a ms t i n u e g a t l o v y l p p u sv n i 5 . 6 o t 3 . 0 -v e g a t l o v t u p t u ov t u o 5 . 6 o t 3 . 0 -v + 2 c , + 1 c - e g a t l o v n i p v o t 3 . 0 - t u o 3 . 0 +v s n i p r e h t o l l a - e g a t l o v n i p v o t 3 . 0 - n i 3 . 0 +v v t u o n o i t a r u d t i u c r i c t r o h st c s e t i n i f e d n is t n e i b m a o t n o i t c n u j , e c n a t s i s e r l a m r e h t ) 1 ( a j 0 4w / c e g n a r e r u t a r e p m e t t n e i b m a g n i t a r e p ot a 5 8 + o t 0 4 -c e g n a r e r u t a r e p m e t n o i t c n u jt j 0 5 1 + o t 0 4 -c e g n a r e r u t a r e p m e t e g a r o t st g t s 0 5 1 + o t 5 6 -c s 0 3 o t s 0 1 ) g n i r e d l o s ( w o l f e r r it d a e l 0 6 2c ) l e d o m y d o b n a m u h ( g n i t a r d s e ) 2 ( v d s e 2v k r e t e m a r a pl o b m y ss n o i t i d n o cn i mp y tx a ms t i n u s n o i t a c i f i c e p s l a c i r t c e l e p m u p e g r a h c e g a t l o v y l p p u s t u p n iv n i 0 . 35 . 5v l a t o t m u m i x a m t n e r r u c t u p t u o i ) x a m ( t u o v n i , s t n e r r u c d e l e v i t c a l l a f o m u s , v 4 . 3 > v ) x a m ( t u o . x a m s m 0 0 5 , v 2 . 4 = 4 3 4a m t n e r r u c d e l l a u d i v i d n i t h g i l k c a b n i a m , g n i t t e s i x m s g n i t t e s l a n i m o n4 . 02 3a m t n e r r u c d e l l a u d i v i d n i h s a l f / b u s , g n i t t e s i y l f / x s s g n i t t e s l a n i m o n4 . 02 0 1a m d e l l a u d i v i d n i y c a r u c c a t n e r r u c i c c a _ d e l v n i i , v 7 . 3 = t e s a m 4 . 0 =0 3 a v n i i , v 7 . 3 = t e s a m 0 2 =0 . 8 -5 . 1 0 . 8 +% v , y l n o s n i p h s a l f n i i , v 7 . 3 = t e s a m 2 0 1 =2 % g n i h c t a m d e l ) 1 ( i d e l - d e l v n i i , v 7 . 3 = t e s a m 4 . 0 =0 2 a v n i i , v 7 . 3 = t e s a m 0 2 =5 . 3 -5 . 0 5 . 3 +% v , y l n o s n i p h s a l f n i i , v 7 . 3 = t e s a m 2 0 1 =1 exceeding the specifications below may result in permanent damage to the device or device malfunction. operation outside of the parameters specified in the electrical characteristics section is not implied. exposure to absolute maximum rated conditions for extended periods of time may affect device reliability. notes: (1) calculated from package in still air, mounted to a 3? x 4.5?, 4-layer fr4 pcb with thermal vias under the exposed pad per j esd51 standards. (2) tested according to jedec standard jesd22-a114-b.
? 2006 semtech corp. power management SC614 united states patent no. 6,504,422 www.semtech.com 3 power management electrical characteristics (cont.) r e t e m a r a pl o b m y ss n o i t i d n o cn i mp y tx a ms t i n u ) . t n o c ( s n o i t a c i f i c e p s l a c i r t c e l e p m u p e g r a h c e d o m x 5 . 1 o t e d o m x 1 e g a t l o v n o i t i s n a r t g n i l l a f v x 1 s n a r t i t u o v , ) d e l / a m 0 1 ( a m 0 7 = t u o v 4 =7 0 . 4v e d o m x 1 o t e d o m x 5 . 1 s i s e r e t s y h v x 1 t s y h i t u o v , ) d e l / a m 0 1 ( a m 0 7 = t u o v 4 =0 0 1v m e d o m x 2 o t e d o m x 5 . 1 e g a t l o v n o i t i s n a r t g n i l l a f v x 5 . 1 s n a r t i t u o v , ) d e l / a m 0 1 ( a m 0 7 = t u o v 4 =2 9 . 2v e d o m x 5 . 1 o t e d o m x 2 s i s e r e t s y h v x 5 . 1 t s y h i t u o v , ) d e l / a m 0 1 ( a m 0 7 = t u o v 4 =0 0 2v m t n e r r u c n w o d t u h si ) f f o ( q v , d n g = n e n i t , v 2 . 4 = a c 5 2 =1 . 00 . 1 a v , d n g = n e n i t , v 2 . 4 = a c 5 8 + o t c 0 4 - =2 1 ) 2 ( t n e r r u c t n e c s e i u q l a t o ti q v = n e ( p e e l s n i , 1 = p e e l s , ) y t i v i t c a e c a f r e t n i l a i r e s o n 0 5 ) 3 ( a i , e d o m x 1 t u o a m 8 . 0 =0 0 . 15 8 . 1a m i , e d o m x 5 . 1 t u o f , a m 8 . 0 = p m u p z h k 0 5 2 =4 . 1 i , e d o m x 2 t u o f , a m 8 . 0 = p m u p z h k 0 5 2 =8 . 10 . 3 i , e d o m x 5 . 1 t u o f , a m 8 . 0 = p m u p z h m 3 3 . 1 =3 . 2 i , e d o m x 2 t u o f , a m 8 . 0 = p m u p z h m 3 3 . 1 =5 . 32 . 5 e t a t s - f f o k n i s t n e r r u c t n e r r u c e g a k a e l i ) f f o ( d e l v n i v = n e v = d e l v 2 . 4 =1 . 01a e z i s p e t s t n e r r u c c a di p s c a d r e t s i g e r t i b - 84 . 0a m y t i r a e n i l - n o n l a i t n e r e f f i dl n d1 b s l y c n e u q e r f p m u pf p m u p v n i 0 = l e s f , v 2 . 3 =0 5 2z h k v n i 1 = l e s f , v 2 . 3 =3 3 . 1z h m ) m i d s , m i d m , l f , n e , l e s a ( s n o i t a c i f i c e p s l a c i r t c e l e o / i l a t i g i d d l o h s e r h t h g i h t u p n iv h i v n i v 5 . 5 =6 . 1v d l o h s e r h t w o l t u p n iv l i v n i v 3 =4 . 0v t n e r r u c h g i h t u p n ii h i v n i v 5 . 5 =0 1a t n e r r u c w o l t u p n ii l i v n i v 5 . 5 =0 1a y c n e u q e r f t u p n i m u m i x a m ) s n i p m i d s d n a m i d m ( f m i d 01z h k t u p n i m u m i x a m ) n i p l f ( y c n e u q e r f f l f e l c y c y t u d % 0 501z h k
? 2006 semtech corp. power management SC614 united states patent no. 6,504,422 www.semtech.com 4 electrical characteristics (cont.) r e t e m a r a pl o b m y ss n o i t i d n o cn i mp y tx a ms t i n u i 2 s n o i t a c i f i c e p s s u b e c a f r e t n i c e g a t l o v t u p n i l a t i g i dv l i - b l c s d n a a d s4 . 0v v h i - b l c s d n a a d s6 . 1 e g d e l w o n k c a a d s e g a t l o v t u p t u o v l o v n i i , v 3 = ) a d s ( n i - b a m 3 =4 . 0v t n e r r u c t u p n i l a t i g i di n i - b 2 . 0 -2 . 0a e c n a t i c a p a c n i p o / ic n i 0 1f p i 2 s n o i t a c i f i c e p s g n i m i t c y c n e u q e r f k c o l cf l c s 0 0 40 4 4z h k d o i r e p w o l l c s ) 2 ( t w o l 3 . 1s d o i r e p h g i h l c s ) 2 ( t h g i h 6 . 0s e m i t d l o h a t a d ) 2 ( t t a d ; d h 0s e m i t p u t e s a t a d ) 2 ( t t a d ; u s 0 0 1s n e m i t p u - t r a t s e c a f r e t n i ) 2 ( t n e h g i h d e l l u p s i n e r e t f a e m i t p u - t r a t s s u b0 5 3s d e t a e p e r r o f e m i t p u t e s n o i t i d n o c t r a t s ) 2 ( t a t s ; u s 6 . 0s d e t a e p e r r o f e m i t d l o h n o i t i d n o c t r a t s ) 2 ( t a t s ; d h 6 . 0s p o t s r o f e m i t p u t e s n o i t i d n o c ) 2 ( t o t s ; u s 6 . 0s n e e w t e b e m i t e e r f s u b t r a t s d n a p o t s ) 2 ( t f u b 3 . 1s n o i t c e t o r p t l u a f t i u c r i c t r o h s t u p t u o t i m i l t n e r r u c i ) c s ( t u o v t u o d n g =0 0 3a m e r u t a r e p m e t r e v o ) 4 ( t p t o ) c 0 1 = s i s e r e t s y h ( d l o h s e r h t g n i s i r0 6 1c e g a t l o v r e v o t u p t u ov p v o 7 . 5v notes: (1) led matching applies to current sinks set to the same current only. matching is calculated as follows: ( ) () % 100 i i i i i min max min max led led ? + ? = ? (2) guaranteed by design. (3) the total quiescent current in sleep mode will increase when serial bus activity occurs, and with the clock frequency of th at bus activity. (4) when the junction temperature exceeds the over temperature (ot) threshold, the device will enter sleep mode with the conten ts of all registers retained. the device will exit sleep mode and re-commence normal operation as soon as the junction temperature drops by more than the ot hysteresis.
? 2006 semtech corp. power management SC614 united states patent no. 6,504,422 www.semtech.com 5 power management block diagram mahxlife tm fractional charge pump (1x, 1.5x, 2x) oscillator digital interface and logic control current setting dac vin en sda scl vout m1 c1+ c1- c2+ c2- fl control override mdim sdim vin vout asel pull high or low to set slave address 11 17 2 7 8 4 3 5 6 10 13 15 14 9 16 22 23 24 1 18 12 21 m2 m3 m4 s1/fl3 s2/fl2 s3/fl1 gnd gnd 20 19
? 2006 semtech corp. power management SC614 united states patent no. 6,504,422 www.semtech.com 6 pin configuration e c i v e de g a k c a p t r t l m 4 1 6 c s ) 1 ( 4 2 - q p l m ) 2 ( b d 4 1 6 c s ) 3 ( d r a o b n o i t a r t s n o m e d b v e 4 1 6 c s ) 4 ( d r a o b n o i t a u l a v e notes: (1) lead free product. this product is fully weee and rohs compliant. (2) only available in tape and reel packaging. a reel contains 3000 devices. (3) the demonstration board showcases the most common uses for this part, running at maximum current settings. (4) the evaluation board is user-configurable and allows the user to communicate with the part using a graphical user interface on a personal computer with a usb connection. contact factory for availability. marking information 614 yyww yy = two-digit year of manufacture ww = two-digit week of manufacture xxxxx = lot number top mark xxxxx xxxxx mlp24: 4x4 24 lead top view 1 2 3 4 6 5 7 8 9 10 11 12 24 23 22 21 20 19 18 17 16 15 13 14 t m1 en sdim mdim asel fl s3/fl1 vin vout c2+ c2- c1- m2 m3 m4 gnd s1/fl3 s2/fl2 sda scl vout c1+ vin gnd ordering information
? 2006 semtech corp. power management SC614 united states patent no. 6,504,422 www.semtech.com 7 power management pin descriptions # n i pe m a n n i pn o i t c n u f n i p 11 m . d e s u t o n f i d e t c e n n o c n u e v a e l . 1 d e l t h g i l k c a b n i a m r o f t u p n i k n i s t n e r r u c 2n e. h g i h e v i t c a , t u p n i e l b a n e 3m i d s. n o = w o l , f f o = h g i h . s d e l t h g i l k c a b b u s r o f n i p g n i m m i d 4m i d m. n o = w o l , f f o = h g i h . s d e l t h g i l k c a b n i a m r o f n i p g n i m m i d 5l e s a o w t s w o l l a s i h t . s s e r d d a e c i v e d e h t n i t i b e n o t e s o t h g i h r o w o l d e l l u p e b n a c n i p . t c e l e s s s e r d d a . s u b e m a s e h t o t d e t c e n n o c e b o t s e c i v e d 6l f. f f o = w o l , n o = h g i h . s d e l h s a l f r o f n i p l o r t n o c 7a d si 2 . d e r i u q e r s i r o t s i s e r p u - l l u p l a n r e t x e n a . ) l a n o i t c e r i d - i b ( a t a d l a i r e s c 8l c si 2 . d e r i u q e r s i r o t s i s e r p u - l l u p l a n r e t x e n a . t u p n i k c o l c c 9t u o v. 6 1 n i p o t t c e n n o c . t u p t u o p m u p e g r a h c 0 1+ 1 c. n o i t c e n n o c e v i t i s o p 1 c r o t i c a p a c t e k c u b 1 1n i v. 7 1 n i p o t t c e n n o c . t u p n i e g a t l o v y r e t t a b 2 1d n g. e n a l p d n u o r g o t y l t c e r i d t c e n n o c . n i p d n u o r g 3 1- 1 c. n o i t c e n n o c e v i t a g e n 1 c r o t i c a p a c t e k c u b 4 1- 2 c. n o i t c e n n o c e v i t a g e n 2 c r o t i c a p a c t e k c u b 5 1+ 2 c. n o i t c e n n o c e v i t i s o p 2 c r o t i c a p a c t e k c u b 6 1t u o v t u o v l l a . 1 2 n i p o t r o t i c a p a c c i m a r e c f 1 a g n i s u n i p s i h t e l p u o c e d . t u p t u o p m u p e g r a h c . r o t i c a p a c s i h t f o p o t e h t o t d e r r a t s e b d l u o h s s n o i t c e n n o c 7 1n i v . 1 2 n i p o t r o t i c a p a c c i m a r e c f 2 . 2 a g n i s u n i p s i h t e l p u o c e d . t u p n i e g a t l o v y r e t t a b 8 11 l f / 3 s h s a l f m u m i x a m r o f 3 l f / 1 s d n a 2 l f / 2 s h t i w e n i b m o c . h s a l f r o t h g i l k c a b b u s r o f t u p n i k n i s t n e r r u c . d e s u t o n f i d e t c e n n o c n u e v a e l . y t i l i b a p a c t n e r r u c 9 12 l f / 2 s h s a l f m u m i x a m r o f 1 l f / 3 s d n a 3 l f / 1 s h t i w e n i b m o c . h s a l f r o t h g i l k c a b b u s r o f t u p n i k n i s t n e r r u c . d e s u t o n f i d e t c e n n o c n u e v a e l . y t i l i b a p a c t n e r r u c 0 23 l f / 1 s h s a l f m u m i x a m r o f 1 l f / 3 s d n a 2 l f / 2 s h t i w e n i b m o c . h s a l f r o t h g i l k c a b b u s r o f t u p n i k n i s t n e r r u c . d e s u t o n f i d e t c e n n o c n u e v a e l . y t i l i b a p a c t n e r r u c 1 2d n g. e n a l p d n u o r g o t y l t c e r i d t c e n n o c . n i p d n u o r g 2 24 m . d e s u t o n f i d e t c e n n o c n u e v a e l . 4 d e l t h g i l k c a b n i a m r o f t u p n i k n i s t n e r r u c 3 23 m . d e s u t o n f i d e t c e n n o c n u e v a e l . 3 d e l t h g i l k c a b n i a m r o f t u p n i k n i s t n e r r u c 4 22 m . d e s u t o n f i d e t c e n n o c n u e v a e l . 2 d e l t h g i l k c a b n i a m r o f t u p n i k n i s t n e r r u c -l a m r e h t d a p d e t c e n n o c t o n . s a i v e l p i t l u m g n i s u e n a l p d n u o r g o t t c e n n o c . s e s o p r u p g n i k n i s t a e h r o f d a p . y l l a n r e t n i
? 2006 semtech corp. power management SC614 united states patent no. 6,504,422 www.semtech.com 8 register map note: all registers are readable and writable. definition of terms: 0: leave this bit as a 0. xen: on/off control for individual current sinks. set to 1 to enable, clear to 0 to disable. flmode: flash mode control bit. set to 1 for flash mode, clear to 0 for normal mode. sleep: sleep mode control bit. set to 1 to put into low current mode (bandgap, uvlo monitor and interface monitoring stay on, all other circuitry shut down), clear to 0 for normal mode. swres: software reset bit. set to 1 to reset all registers (swres clears automatically and does not require an additional i 2 c write). fsel: frequency select bit. allows the choice between two different switching frequencies, set to 1 for 1.33mhz, clear to 0 for 250khz. s s e r d d a7 d6 d5 d4 d3 d2 d1 d0 dt e s e r e u l a v n o i t p i r c s e d 0 0 x 0 0n e 1 l f / 3 sn e 2 l f / 2 sn e 3 l f / 1 sn e 4 mn e 3 mn e 2 mn e 1 m0 0 x 0f f o / n o d e l l o r t n o c 1 0 x 0 0 a m 2 3 = 0 5 x 0 , f f o = 0 0 x 0 , t i b / a m 4 . 0 , g n i t t e s t n e r r u c t i b - 7 0 0 x 0t n e r r u c 1 m l o r t n o c 2 0 x 0 0 a m 2 3 = 0 5 x 0 , f f o = 0 0 x 0 , t i b / a m 4 . 0 , g n i t t e s t n e r r u c t i b - 7 0 0 x 0t n e r r u c 2 m l o r t n o c 3 0 x 0 0 a m 2 3 = 0 5 x 0 , f f o = 0 0 x 0 , t i b / a m 4 . 0 , g n i t t e s t n e r r u c t i b - 7 0 0 x 0t n e r r u c 3 m l o r t n o c 4 0 x 0 0 a m 2 3 = 0 5 x 0 , f f o = 0 0 x 0 , t i b / a m 4 . 0 , g n i t t e s t n e r r u c t i b - 7 0 0 x 0t n e r r u c 4 m l o r t n o c 5 0 x 0 a m 2 0 1 = f f x 0 , f f o = 0 0 x 0 , t i b / a m 4 . 0 , g n i t t e s t n e r r u c t i b - 8 0 0 x 03 l f / 1 s l o r t n o c t n e r r u c 6 0 x 0 a m 2 0 1 = f f x 0 , f f o = 0 0 x 0 , t i b / a m 4 . 0 , g n i t t e s t n e r r u c t i b - 8 0 0 x 02 l f / 2 s l o r t n o c t n e r r u c 7 0 x 0 a m 2 0 1 = f f x 0 , f f o = 0 0 x 0 , t i b / a m 4 . 0 , g n i t t e s t n e r r u c t i b - 8 0 0 x 01 l f / 3 s l o r t n o c t n e r r u c 8 0 x 0 0e d o m l fp e e l ss e r w sl e s f1 l f0 l f00 2 x 0l o r t n o c r e t s i g e r
? 2006 semtech corp. power management SC614 united states patent no. 6,504,422 www.semtech.com 9 power management register map (cont.) fl1,0: control override bits for s1/fl3, s2/fl2 and s3/fl1. enable control is transferred to the fl pin (assuming the leds are first enabled) based on the following table: 1 l f0 l fs u t a t s l o r t n o c n i p l f 00 . d e l b a s i d n i p l f - s t i b r e t s i g e r y b d e n i a t n i a m l o r t n o c 01 . n i p l f e h t y b d e l l o r t n o c e l b a n e 1 l f / 3 s 10 . n i p l f e h t y b d e l l o r t n o c s e l b a n e 2 l f / 2 s , 1 l f / 3 s 11 . n i p l f e h t y b d e l l o r t n o c s e l b a n e 3 l f / 1 s , 2 l f / 2 s , 1 l f / 3 s SC614 slave address following a start condition, the master must output the address of the slave it is accessing. the most significant six bits of the slave address are the device type identifier (id). for the SC614 this is fixed at 111000[asel]. the next significant bit addresses a particular device. a system can have up to two SC614 devices on the same bus. the two addresses are defined by the state of the asel input (see table below). r e i f i t n e d i e p y t e c i v e ds s e r d d a e c i v e dw / r 111000 0 = d n g o t l e s a n i p 1 = n i v o t l e s a n i p x
? 2006 semtech corp. power management SC614 united states patent no. 6,504,422 www.semtech.com 10 state diagrams when the SC614 is first enabled, it starts up in sleep mode, with the registers at their reset values and the charge pump off. the bandgap reference will be operating, the input voltage will be monitored for uvlo and the serial interface will be monitored for any activity. this is the lowest power state for the device where it can be communicated with. in order to activate the charge pump it is necessary to clear the sleep bit to 0 to enter run mode. when in run mode the charge pump is activated in 1x mode with vout = 1.5v, and all of the optional functions of the device may be accessed. shutdown sleep mode ( sleep = 1 ) power off vin high , en low en = high vin , en high run mode ( sleep = 0 ) sleep = 0 lowest power state. all internal functions powered down bandgap up, uvlo and serial interface monitoring active only bandgap up, uvlo and serial interface monitoring active, charge pump running with vout = 1.5v start-up
? 2006 semtech corp. power management SC614 united states patent no. 6,504,422 www.semtech.com 11 power management state diagrams (cont.) power management sleep mode (register contents stored) shutdown (en low) sleep mode (register contents reset) sleep = 1 from any run mode swrst = 1 from any run mode en low from any mode sleep = 0 return to previous mode sleep = 0 run mode there are three options for powering down the SC614 (other than writing 0x00 to each current control register or the led on/off control register): sleep mode (sleep = 1) setting this bit to 1 at any time will power down the charge pump. the register contents will be stored, the bandgap reference will remain active, and uvlo and serial interface monitoring will continue. clearing this bit will resume operation as before. sleep mode from reset (swres = 1) setting swres to 1 will reset all registers (clearing the swres bit), causing the part to enter sleep mode but with all registers at their reset values (0x00 for registers 0x00 through 0x07, 0x20 for control register 0x08 (sleep = 1). upon clearing the sleep bit, the SC614 will enter run mode and will require writing to the registers to commence driving leds. shutdown (en low) all internal functions are powered down. pulling en high will enter sleep mode with all registers reset. device operation with all leds disabled if the SC614 is driving leds and then all leds are disabled, the device reverts to 1x mode with a nominal output voltage of 3v. this decreases the response time when the leds are enabled once more. quiescent current in this mode will be 700 a (nom).
? 2006 semtech corp. power management SC614 united states patent no. 6,504,422 www.semtech.com 12 general operation the SC614 contains a fractional charge pump, mode selection circuitry, serial i/o logic, serial data registers and current regulation circuitry for 7 led outputs. all are depicted in the block diagram on page 5. the fractional charge pump multiplies the input voltage by 1, 1.5 or 2 times the input voltage. the charge pump switches at a fixed frequency that is bit selectable to 1.33mhz or 250khz. the default frequency is 250khz. the charge pump does not switch during 1x mode, saving power and improving efficiency. the mode selection circuitry automatically selects the mode as 1x, 1.5x or 2x based on circuit conditions such as led voltage, input voltage and load current. 1x is the most efficient mode, followed by 1.5x and 2x modes. at lower input voltages a stronger mode may be needed to maintain regulation. if so, the mode will change first to 1.5x and then later to 2x. 2x mode usually operates for a much shorter run time compared to 1x mode, and 2x mode maintains the output until the battery is discharged to 3v or less. the led requiring the highest voltage drop will determine the output voltage needed to drive all outputs with sufficient anode voltage. comparing all cathodes and regulating vout for the led with the lowest cathode voltage ensures sufficient bias for all leds. the led outputs are controlled through the serial data registers, found in the register map on page 8. led on/ off functions are independently controlled, so that any combination of leds may be switched on. seven (7) current regulating circuits sink currents from the leds as set by the current control registers. for lcd backlighting applications current matching is crucial, and leds with matched forward voltage will produce the best possible matched currents. the SC614 is capable of dealing with v f mis-matches up to 0.5v. for best matching performance, however, it is recommended that the led to led difference, v f , be under 250mv. designing for lowest possible battery current the battery current and efficiency of the SC614 are mostly dependent on the charge pump mode of operation. to get the best performance from the SC614 it is better to use leds with consistantly lower v f . lower v f will keep the charge pump in 1x mode longer and will use less battery current, extending the run time of the battery. mode transition threshold voltage and hysteresis mode transition threshold voltage refers to the input voltage at the point when the charge pump changes from a weaker mode (lower numerically) to a stronger mode (higher numerically). v trans1x is the transition from 1x to 1.5x mode, and v trans1.5x is the transition from 1.5x to 2x mode. mode transition voltages v trans1x and v trans1.5x can be estimated by the following equations: v trans1x = v f + v iled + i out 1.0 v trans1.5x = (v f + v iled + i out 5.5) / 1.5 where v f is the highest forward voltage of the operating leds, v iled is the current sink voltage for that led (typically v iled =150mv) and i out is the sum of all operating led currents. the mode transition circuitry has hysteresis built in to prevent the device from toggling between modes when the input voltage is right at the threshold of mode change. there is 100mv of hysteresis between 1.5x and 1x modes and 200mv of hysteresis between 2x and 1.5x modes. efficiency power efficiency can be estimated for any particular battery voltage as follows: = [v out i out / v in (i out mode+i q )] 100 % where: v out = v f + v iled (defined in the above section). and, i q = 1ma in 1x mode, 1.4ma in 1.5x mode and 1.8ma in 2x mode (250khz). led current accuracy the led current is set by the current control registers 0x01 through 0x07. the guaranteed accuracy of any current sink is +/-8% at a current setting of 20ma, with the typical accuracy much higher at +/-1.5%. for example, if the current control registers are configured such that each led current will be 20ma (0x32 written to register 0x01 through 0x07), the actual led currents applications information
? 2006 semtech corp. power management SC614 united states patent no. 6,504,422 www.semtech.com 13 power management would be between 18.4ma and 21.6ma (+/-8%). all 7 outputs meet this requirement over the industrial temperature range. to calculate the accuracy based upon the actual measured led current, i led_acc , use the following formula: ( ) % 100 i i i i ) set ( led ) set ( led ) measured ( led acc _ led ? ? = current matching the current matching percentage is a figure that represents how closely matched leds are that are set to the same current. for any particular led within a group of leds set to the same current, the matching is the i for that led from the average of the minimum and maximum value of the group (i.e. the center of the measured current range) expressed as a percentage of that average. current matching is calculated as follows: % 100 2 i i i or % 100 2 i i i i min max min min max max led _ led ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? + ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? + = which can be reduced to: ( ) () % 100 i i i i i min max min max led _ led ? + ? = protection circuitry the SC614 also provides protection circuitry that prevents the device from operating in an unspecified state. these include output over-voltage protection (ovp), over-temperature protection (otp), over-current protection (ocp) and short-circuit protection (scp). output over-voltage protection output over-voltage protection is included to prevent the SC614 from generating an output voltage that could damage other devices connected to it such as load leds any bypass capacitors. when the output voltage exceeds 5.7v, the ovp circuitry disables the charge pump until the output voltage decreases to an acceptable level. usually the only reason for the output voltage to trip ovp is if one of the leds goes open. if this happens the SC614 will raise the output voltage to attempt to bring applications information (cont.) that led current back into regulation. when the ovp trip point is reached, the charge pump will be turned off. any current sinks that measure close to ground will be turned off in an attempt to isolate the faulty led. once the output voltage drops enough the charge pump will resume operation. over-temperature protection the over-temperature protection circuitry helps to prevent the device from overheating and experiencing a catastrophic failure. when the junction temperature exceeds 160c the output is disabled and the device enters sleep mode. all register settings are retained. the junction temperature must drop by more than the hysteresis of 10c before the part exits sleep mode and re-commences normal operation. over-current and short circuit protection adaptive current limit circuitry is provided to protect the device from various levels of shorts from resistive to full shorts as well as to limit in-rush current at start-up and during mode transitions. the current limit levels adjust to the total output current set for the leds and thus will be higher when very high levels of currents are programmed, such as for flash operation. the current limit levels are set to ensure that the device will not current limit under normal operation. when an output short circuit occurs, the device folds back the current limit level to a nominal 300ma. if sustained current limit occurs the device may shut down due to internal heating triggering the otp circuitry. capacitor selection the SC614 is designed to use low-esr ceramic capacitors for all four external capacitors: input, output and charge pump bucket capacitors. ideal performance is achieved when the bucket capacitors (c3 and c4 in the application circuit) are exactly equal. note: it is recommended that x5r or x7r capacitors are used for best performance. thermal resistance and heat management the SC614 is packaged in a thermally efficient mlpq24 package that has a thermal pad to remove the heat from the part. it is intended to be connected using multiple vias to the ground plane, and the thermal resistance rating of 40c/w reflects this. a good layout will enable the part to operate at maximum output current ratings without tripping the otp circuitry.
? 2006 semtech corp. power management SC614 united states patent no. 6,504,422 www.semtech.com 14 applications information (cont.) layout guidelines the following layout is suggested (shown as three-layer (top, bottom and ground layer) only for clarity). c1 is the input capacitor which should be placed close to pin 17. c2 is the output capacitor which should be placed close to pin 16. the capacitors c3 and c4 are the bucket capacitors which can carry up to the full load current of 434ma pulsed for one half clock cycle (at either 250khz or 1.33mhz depending upon selected operating frequency). multiple vias should be used whenever it is necessary to change layers on nets connecting to cin, vout, c1+, c1-, c2+ and c2-. as mentioned before, the thermal pad should connect to ground using multiple vias, with 4 vias recommended. top copper and top silkscreen layout guidelines schematic c2 1u c1 2u2 c3 1u c4 1u vin 11 vin 17 en 2 sda 7 scl 8 asel 5 sdim 3 md i m 4 fl 6 vout 9 vout 16 m1 1 m2 24 m3 23 m4 22 s1/fl3 20 s2/fl2 19 s3/fl1 18 gnd 12 gnd 21 tpad 25 c1+ 10 c1- 13 c2+ 15 c2- 14 u1 SC614 vbat
? 2006 semtech corp. power management SC614 united states patent no. 6,504,422 www.semtech.com 15 power management bottom copper ground layer applications information (cont.)
? 2006 semtech corp. power management SC614 united states patent no. 6,504,422 www.semtech.com 16 application examples main backlight plus flash d1 led c2 1u 434ma max (500ms) d2 led d3 led d4 led d5 led 32ma max 32ma max 32ma max 32ma max 306ma max. c1 2u2 c3 1u c4 1u vin 11 vin 17 en 2 sda 7 scl 8 asel 5 sdim 3 md i m 4 fl 6 vout 9 vout 16 m1 1 m2 24 m3 23 m4 22 s1/fl3 20 s2/fl2 19 s3/fl1 18 gnd 12 gnd 21 tpad c1+ 10 c1- 13 c2+ 15 c2- 14 u1 SC614 en sda scl sdim fl mdim 328ma max continuous vbat r1 pull-up r2 pull-up vlogic note: r1 and r2 pull-up resistors are a requirement of the i2c specif ication main backlight flash features: ? up to 4 led main backlight with up to 32ma per led ? pwm dimming of backlight using mdim pin ? up to 306ma flash capability controlled by fl pin register settings (20ma backlight currents and 300ma flash current used as an example): 0x00: set to 0x7f to enable all 7 current sinks for use 0x01 through 0x04: set to 0x32 for 20ma per current sink 0x05 through 0x07: set to 0xfa for 100ma per current sink, 300ma total 0x08: set to 0x46 for flash mode enabled, 250khz charge pump frequency, fl pin controls s1/fl3, s2/fl2 and s3/fl1
? 2006 semtech corp. power management SC614 united states patent no. 6,504,422 www.semtech.com 17 power management application examples (cont.) main backlight plus sub-backlight d1 led c2 1u 434ma max (500ms) d2 led d3 led d4 led d5 led 32ma max 32ma max 32ma max 32ma max c1 2u2 c3 1u c4 1u vin 11 vin 17 en 2 sda 7 scl 8 asel 5 sdim 3 md im 4 fl 6 vout 9 vout 16 m1 1 m2 24 m3 23 m4 22 s1/fl3 20 s2/fl2 19 s3/fl1 18 gnd 12 gnd 21 tpad c1+ 10 c1- 13 c2+ 15 c2- 14 u1 SC614 en scl sda fl sdim mdim vbat r1 pull-up r2 pull-up vlogic note: r1 and r2 pull-up resistors are a requirement of the i2c specif ication sub backlight main backlight 102ma max 102ma max 102ma max d6 led d7 led 328ma max continuous features: ? up to 4 led main backlight with up to 32ma per led ? pwm dimming of main backlight using mdim pin ? up to 3 led sub-backlight with up to 32ma per led ? pwm dimming of sub-backlight using sdim pin register settings (20ma backlight currents used as an example): 0x00: set to 0x7f to enable all 7 current sinks for use (or as needed if less) 0x01 through 0x07: set to 0x32 for 20ma per current sink 0x08: set to 0x00 for flash mode disabled (fl pin inactive) and 250khz charge pump frequency
? 2006 semtech corp. power management SC614 united states patent no. 6,504,422 www.semtech.com 18 application examples (cont.) main backlight plus sub-backlight plus flash d1 led c2 1u 434ma max (500ms) d2 led d3 led d4 led d5 led 102ma max 102ma max 102ma max 102ma max c1 2u2 c3 1u c4 1u vin 11 vin 17 en 2 sda 7 scl 8 asel 5 sdim 3 md i m 4 fl 6 vout 9 vout 16 m1 1 m2 24 m3 23 m4 22 s1/fl3 20 s2/fl2 19 s3/fl1 18 gnd 12 gnd 21 tpad c1+ 10 c1- 13 c2+ 15 c2- 14 u1 SC614 sda en sdim scl fl mdim vbat r1 pull-up vlogic r2 pull-up note: r1 and r2 pull-up resistors are a requirement of the i2c specif ication main backlight sub backlight 102ma max 102ma max 102ma max d6 led d7 led r3 balance r4 balance flash 328ma max continuous features: ? up to 4 led main backlight with up to 32ma per led ? pwm dimming of main backlight using mdim pin ? up to 2 led sub-backlight with up to 32ma per led using resistor current balancing ? pwm dimming of sub-backlight using sdim pin ? up to 204ma flash capability controlled by fl pin register settings (20ma backlight currents and 200ma flash current used as an example): 0x00: set to 0x7f to enable all 7 current sinks for use 0x01 through 0x04: set to 0x32 for 20ma per current sink 0x05: set to 0x64 for 40ma for this current sink (20ma per led) 0x06 and 0x07: set to 0xfa for 100ma per current sink, 200ma total 0x08: set to 0x44 for flash mode enabled, 250khz charge pump frequency, fl pin controls s2/fl2 and s3/fl1
? 2006 semtech corp. power management SC614 united states patent no. 6,504,422 www.semtech.com 19 power management application examples (cont.) main backlight plus rgb indicator d1 led c2 1u d2 led d3 led d4 led d5 c1 2u2 c3 1u c4 1u vin 11 vin 17 en 2 sda 7 scl 8 asel 5 sdim 3 md im 4 fl 6 vout 9 vout 16 m1 1 m2 24 m3 23 m4 22 s1/fl3 20 s2/fl2 19 s3/fl1 18 gnd 12 gnd 21 tpad c1+ 10 c1- 13 c2+ 15 c2- 14 u1 SC614 sda en sdim scl fl mdim vbat r1 pull-up vlogic r2 pull-up note: r1 and r2 pull-up resistors are a requirement of the i2c specification main backlight rgb indicator rgb_led 102ma max 102ma max 102ma max 102ma max 328ma max continuous 102ma max 102ma max 102ma max 434ma max (500ms) features: ? up to 4 led main backlight with up to 32ma per led ? pwm dimming of backlight using mdim pin ? 3 current sinks for rgb with up to 32ma per led ? dimming and color rotation of rgb over i 2 c interface register settings (20ma backlight currents and as required on the fly rgb current used as an example): 0x00: set to 0x7f to enable all 7 current sinks for use 0x01 through 0x04: set to 0x32 for 20ma per current sink 0x05 through 0x07: set to as required on the fly for each color 0x08: set to 0x00 for flash mode disabled (fl pin inactive) and 250khz charge pump frequency
? 2006 semtech corp. power management SC614 united states patent no. 6,504,422 www.semtech.com 20 using the i 2 c serial port the i 2 c general specification the SC614 is a read-write slave-mode i 2 c device and complies with the philips i 2 c standard version 2.1 dated january 2000. the SC614 has nine user-accessible internal 8-bit registers. the i 2 c interface has been designed for program flexibility, in that once the slave address has been sent to the SC614 enabling it to be a slave transmitter/receiver any register can be written or, read from independently of each other. while there is no auto increment/decrement capability in the SC614 i 2 c logic, a tight software loop can be designed to randomly access the next register independent of which register you begin accessing. the start and stop commands frame the data- packet and the repeat start condition is allowed if necessary. SC614 limitations to the i 2 c specifications seven bit addressing is used and ten bit addressing is not allowed. any general call address will be ignored by the SC614. the SC614 is not cbus compatible. finally, the SC614 can operate in standard mode (100kbit/s) or fast mode (400kbit/s). supported formats direct format - write: the simplest format for an i 2 c write is the direct format write. after the master sends a start condition, the slave address is sent followed by an eighth bit indicating a write. the SC614 then acknowledges that it is being addressed, and the master responds with an 8-bit data byte consisting of the target register address. the slave acknowledges and the master sends the appropriate 8-bit data byte. once again the slave acknowledges and the master terminates the transfer with a stop condition. s s s e r d d a e v a l s wa s s e r d d a r e t s i g e ra a t a da p s: start condition slave address: 7 bit w: write = 0 register address: 8 bit a: acknowledge (sda low) data: 8 bit p: stop condition shaded represents transmission from master to slave and unshaded represents transmission from slave to master. combined format (read/write): after a start condition, the slave address is sent followed by an eighth bit indicating a write. the SC614 then acknowledges that it is being addressed, and the master responds with an 8 bit data byte consisting of the target register address. the slave acknowledges once more and the master sends the repeated start condition. once again, the slave address is sent, followed by an eighth bit indicating a read or write. the slave responds with an acknowledge. if the command was a write, the master sends the appropriate 8-bit data byte. once again the slave acknowledges and the master terminates the transfer with a stop condition. if the command was a read, the slave sends the appropriate 8-bit data byte, to which the master sends a not acknowledge and then terminates the transfer with a stop condition. s s s e r d d a e v a l s wa s s e r d d a r e t s i g e ra r s s s e r d d a e v a l s w / ra a t a d ) 1 ( n / a ) 1 ( p s: start condition n: not acknowledge(sda high) (1) w: write = 0 p: s top condition a: acknowledge (sda low) slave address: 7 bit sr: repeated start condition register address: 8 bit r: read = 1 data: 8 bit shaded represents transmission from master to slave and unshaded represents transmission from slave to master. (1) not shaded because transfer direction depends upon r/w bit.
? 2006 semtech corp. power management SC614 united states patent no. 6,504,422 www.semtech.com 21 power management stop separated reads: a further form of read is available which is, in effect, an extension of the combined format read. this format allows a master to set up the register address pointer for a read, and return to that slave some time later to read the data. after a start condition, the slave address is sent, followed by a write. the SC614 then acknowledges that it is being addressed, and the master responds with the 8-bit target register address. the master then sends a stop or repeated start condition, and may address another slave. some time later the master sends a start or repeated start condition, and a valid slave address is sent, followed by a read. the SC614 then acknowledges and returns the data at the register address location that had previously been set up. s s s e r d d a e v a l s wa s s e r d d a r e t s i g e ra p r e t s a m ( s e s s e r d d a r e h t o ) s e v a l s r s / s s s e r d d a e v a l s ra a t a d n p s: start condition slave address: 7 bit w: write = 0 register address: 8 bit a: acknowledge (sda low) data: 8 bit p: stop condition sr: repeated start r: read = 0 shaded represents transmission from master to slave and unshaded represents transmission from slave to master. using the i 2 c serial port (cont.)
? 2006 semtech corp. power management SC614 united states patent no. 6,504,422 www.semtech.com 22 typical characteristics 30 40 50 60 70 80 90 100 3.0 3.2 3.4 3.6 3.8 4.0 4.2 v bat (v) i bat (ma) led 5-7 = 20ma led v f = 3.276v battery current (sub-only) 0 50 100 150 200 250 3.0 3.2 3.4 3.6 3.8 4.0 4.2 led 1-7 = 20ma led v f = 3.340v v bat (v) i bat (ma) battery current (main and sub) 30 40 50 60 70 80 90 100 3.0 3.2 3.4 3.6 3.8 4.0 4.2 conversion efficiency utilized power efficiency % efficiency v bat (v) led 5-7 = 20ma led v f = 3.276v power ef? ciency (sub-only) 30 40 50 60 70 80 90 100 3.0 3.2 3.4 3.6 3.8 4.0 4.2 conversion efficiency utilized power efficiency v bat (v) led 1-7 = 20ma led v f = 3.340v % efficiency power ef? ciency (main and sub) -3 . 5 -2 . 5 -1 . 5 -0 . 5 0.5 1.5 2.5 3.5 3.03.23.43.63.84.04.2 led matc h ing ( % ) v bat (v) led 1-7 = 20ma typical led matching (main and sub) -6 . 0 -4 . 0 -2 . 0 0.0 2.0 4.0 6.0 3.0 3.2 3.4 3.6 3.8 4.0 4.2 max min min led accuracy % v bat (v) typical led accuracy (main and sub)
? 2006 semtech corp. power management SC614 united states patent no. 6,504,422 www.semtech.com 23 power management typical characteristics (cont.) 300 400 500 600 700 800 900 3.0 3.2 3.4 3.6 3.8 4.0 4.2 v bat (v) i bat (ma) led 1-4 = 20ma led 5-7 = 100ma led v f = 3.388v battery current (main and flash) 40 60 80 100 120 140 3.0 3.2 3.4 3.6 3.8 4.0 4.2 i bat (ma) v bat (v) led 1-4 = 20ma led v f = 3.23v battery current (main only) 30 40 50 60 70 80 90 100 3.03.23.43.63.84.04.2 utilized power efficiency conversion efficiency led 1-4 = 20ma led 5-7 = 100ma led v f = 3.388v % efficiency v bat (v) power ef? ciency (main and flash) 30 40 50 60 70 80 90 100 3.0 3.2 3.4 3.6 3.8 4.0 4.2 utilized power efficiency conversion efficiency led 1-4 = 20ma led v f = 3.23v % e fficiency v bat (v) power ef? ciency (main only)
? 2006 semtech corp. power management SC614 united states patent no. 6,504,422 www.semtech.com 24 e1 e bxn d/2 1 2 n e1 .100 .106 .110 2.55 2.70 2.80 pin 1 indicator 4.15 3.85 4.00 4.15 3.85 .157 .151 .163 .151 .163 aaa c a c (laser mark) d e b a1 a a2 seating plane lxn e/2 bbb c a b d1 inches .020 bsc b .007 bbb aaa n d1 e l e d .011 .100 dim a1 a2 a min .000 - .031 0.30 0.18 .012 0.25 .010 0.50 2.80 0.30 2.55 .004 .004 24 .016 .157 .106 .020 .110 0.10 0.10 24 0.40 4.00 2.70 0.50 bsc millimeters max 0.05 - 1.00 dimensions min 0.00 - nom (.008) .035 .001 max .002 - .040 nom 0.80 0.02 (0.20) 0.90 controlling dimensions are in millimeters (angles in degrees). coplanarity applies to the exposed pad as well as the terminals. notes: 2. 1. outline drawing mlpq-24 4 x 4
? 2006 semtech corp. power management SC614 united states patent no. 6,504,422 www.semtech.com 25 power management this land pattern is for reference purposes only. consult your manufacturing group to ensure your notes: 1. dim x y h k p c g millimeters inches (3.95) .010 .033 .122 .021 .106 .106 (.155) 0.25 0.85 2.70 0.50 2.70 3.10 dimensions company's manufacturing guidelines are met. 4.80 .189 z k g z h (c) x p land pattern mlpq-24 4 x 4 contact information semtech corporation power management products division 200 flynn road, camarillo, ca 93012 phone: (805) 498-2111 fax (805)498-3804 contact information visit us at: www .semt ech.com

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