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c o p y r i g h t ? a n p e c e l e c t r o n i c s c o r p . r e v . a . 3 - n o v . , 2 0 0 9 a p w 7 1 2 0 a w w w . a n p e c . c o m . t w 1 a n p e c r e s e r v e s t h e r i g h t t o m a k e c h a n g e s t o i m p r o v e r e l i a b i l i t y o r m a n u f a c t u r a b i l i t y w i t h o u t n o t i c e , a n d a d v i s e c u s t o m e r s t o o b t a i n t h e l a t e s t v e r s i o n o f r e l e v a n t i n f o r m a t i o n t o v e r i f y b e f o r e p l a c i n g o r d e r s . 5 v t o 1 2 v s u p p l y v o l t a g e , 8 - p i n , s y n c h r o n o u s b u c k p w m c o n t r o l l e r operating with single 5~12v supply voltage or two supply voltages drive dual low cost n-channel mosfets - adaptive shoot-through protection built-in feedback compensation - voltage-mode pwm control - 0~100% duty ratio - fast transient response 2% 0.8v reference - over line, load regulation, and operating temperature programmable over-current protection - using r ds(on) of low-side mosfet hiccup-mode under-voltage protection 118% over-voltage protection adjustable output voltage small converter size - 300khz constant switching frequency - small sop-8 package built-in digital soft-start shutdown control using an external mosfet l e a d f r e e a n d g r e e n d e v i c e s a v a i l a b l e ( r o h s c o m p l i a n t ) f e a t u r e s a p p l i c a t i o n s g e n e r a l d e s c r i p t i o n t h e a p w 7 1 2 0 a i s a f i x e d 3 0 0 k h z f r e q u e n c y , v o l t a g e m o d e , a n d s y n c h r o n o u s p w m c o n t r o l l e r . t h e d e v i c e d r i v e s t w o l o w c o s t n - c h a n n e l m o s f e t s a n d i s d e s i g n e d t o w o r k w i t h s i n g l e 5 ~ 1 2 v o r t w o s u p p l y v o l t a g e ( s ) , p r o v i d i n g e x - c e l l e n t r e g u l a t i o n f o r l o a d t r a n s i e n t s . t h e a p w 7 1 2 0 a i n t e g r a t e s c o n t r o l s , m o n i t o r i n g a n d p r o - t e c t i o n f u n c t i o n s i n t o a s i n g l e 8 - p i n p a c k a g e t o p r o v i d e a l o w c o s t a n d p e r f e c t p o w e r s o l u t i o n . a p o w e r - o n - r e s e t ( p o r ) c i r c u i t m o n i t o r s t h e v c c s u p p l y v o l t a g e t o p r e v e n t w r o n g l o g i c c o n t r o l s . a n i n t e r n a l 0 . 8 v r e f e r e n c e p r o v i d e s l o w o u t p u t v o l t a g e d o w n t o 0 . 8 v f o r f u r t h e r a p p l i c a t i o n s . a n b u i l t - i n d i g i t a l s o f t - s t a r t w i t h f i x e d s o f t - s t a r t i n t e r v a l p r e v e n t s t h e o u t p u t v o l t a g e f r o m o v e r - s h o o t a s w e l l a s l i m i t i n g t h e i n p u t c u r r e n t . t h e c o n t r o l l e r ? s o v e r - c u r r e n t p r o t e c t i o n m o n i t o r s t h e o u t p u t c u r r e n t b y u s i n g t h e v o l t a g e d r o p a c r o s s t h e l o w - s i d e m o s f e t ? s r d s ( o n ) , e l i m i n a t i n g t h e n e e d o f a c u r r e n t s e n s i n g r e s i s t o r . a d d i t i o n a l u n d e r v o l t a g e a n d o v e r v o l t a g e p r o t e c t i o n s m o n i t o r t h e v o l t a g e o n f b p i n f o r s h o r t - c i r c u i t a n d o v e r - v o l t a g e p r o t e c t i o n s . t h e o v e r - c u r r e n t p r o t e c t i o n c y c l e s t h e s o f t - s t a r t f u n c t i o n u n t i l 4 o v e r - c u r r e n t e v e n t s a r e c o u n t e d . p u l l i n g a n d h o l d i n g t h e v o l t a g e o n o c s e t p i n b e l o w 0 . 1 5 v w i t h a n o p e n d r a i n d e v i c e s h u t s d o w n t h e c o n t r o l l e r . p i n c i n f i g u r a t i o n s o p - 8 ( t o p v i e w ) motherboard graphics card high current, up to 20a, dc-dc converters 1 2 3 4 8 7 6 5 phase ocset fb vcc boot ugate gnd lgate
c o p y r i g h t ? a n p e c e l e c t r o n i c s c o r p . r e v . a . 3 - n o v . , 2 0 0 9 a p w 7 1 2 0 a w w w . a n p e c . c o m . t w 2 o r d e r i n g a n d m a r k i n g i n f o r m a t i o n n o t e : a n p e c l e a d - f r e e p r o d u c t s c o n t a i n m o l d i n g c o m p o u n d s / d i e a t t a c h m a t e r i a l s a n d 1 0 0 % m a t t e t i n p l a t e t e r m i n a t i o n f i n i s h ; w h i c h a r e f u l l y c o m p l i a n t w i t h r o h s . a n p e c l e a d - f r e e p r o d u c t s m e e t o r e x c e e d t h e l e a d - f r e e r e q u i r e m e n t s o f i p c / j e d e c j - s t d - 0 2 0 d f o r m s l c l a s s i f i c a t i o n a t l e a d - f r e e p e a k r e f l o w t e m p e r a t u r e . a n p e c d e f i n e s ? g r e e n ? t o m e a n l e a d - f r e e ( r o h s c o m p l i a n t ) a n d h a l o g e n f r e e ( b r o r c l d o e s n o t e x c e e d 9 0 0 p p m b y w e i g h t i n h o m o g e n e o u s m a t e r i a l a n d t o t a l o f b r a n d c l d o e s n o t e x c e e d 1 5 0 0 p p m b y w e i g h t ) . symbol parameter rating unit v cc vcc supply voltage (vcc to gnd) - 0.3 ~ 16 v v boot boot voltage (boot to phase) - 0.3 ~ 16 v ugate voltage (ugate to phase) <400ns pulse width >400ns pu lse width - 5 ~ v boot +0.3 - 0.3 ~ v boot +0.3 v lgate voltage (lgate to gnd) <400ns pulse width >400ns pulse width - 5 ~ v cc +0.3 - 0.3 ~ v cc +0.3 v phase voltage (phase to gnd) <400ns pulse width >400ns pulse width - 10 ~ 30 - 3 ~ 16 v v i/o input voltage ( ocse t, fb to gnd) - 0.3 ~ 7 v maximum junction temperature 150 o c t stg storage temperature - 65 ~ 150 o c t sdr maximum lead soldering temperature, 10 seconds 260 o c a b s o l u t e m a x i m u m r a t i n g s ( n o t e 1 ) t h e r m a l c h a r a c t e r i s t i c s symbol parameter typical value unit q ja junction - to - ambient resistance in free air (note 2) sop - 8 160 o c/w apw7120a handling code temperature range package code package code k : sop-8 operating ambient temperature range e : -20 to 70 o c handling code tr : tape & reel assembly material g : halogen and lead free device apw7120a k : apw7120a xxxxx xxxxx - date code assembly material n o t e 1 : a b s o l u t e m a x i m u m r a t i n g s a r e t h o s e v a l u e s b e y o n d w h i c h t h e l i f e o f a d e v i c e m a y b e i m p a i r e d . e x p o s u r e t o a b s o l u t e m a x i m u m r a t i n g c o n d i t i o n s f o r e x t e n d e d p e r i o d s m a y a f f e c t d e v i c e r e l i a b i l i t y . n o t e 2 : q j a i s m e a s u r e d w i t h t h e c o m p o n e n t m o u n t e d o n a h i g h e f f e c t i v e t h e r m a l c o n d u c t i v i t y t e s t b o a r d i n f r e e a i r .
c o p y r i g h t ? a n p e c e l e c t r o n i c s c o r p . r e v . a . 3 - n o v . , 2 0 0 9 a p w 7 1 2 0 a w w w . a n p e c . c o m . t w 3 symbol parameter range unit v cc vcc supply voltage 4.5 ~ 13.2 v v out converter output voltage 0.8 ~ 7 0%v in v v in converter input voltage 2.2 ~ 13.2 v i out converter output current 0 ~ 20 a t a ambient temperature - 20 ~ 70 o c t j junction temperat ure - 20 ~ 125 o c r e c o m m e n d e d o p e r a t i n g c o n d i t i o n s ( n o t e 3 ) e l e c t r i c a l c h a r a c t e r i s t i c s u n l e s s o t h e r s w i s e s p e c i f i e d , t h e s e s p e c i f i c a t i o n s a p p l y o v e r v c c = 1 2 v , v b o o t = 1 2 v a n d t a = - 2 0 ~ 7 0 o c . t y p i c a l v a l u e s a r e a t t a = 2 5 o c . apw7120 a symbol parameter test conditions min . typ . max . unit supply current i vcc vcc nominal supply current ugate and lgate open - 2.1 6 ma vcc shutdown supply current - 1.5 4 ma power - on - reset rising vcc threshold 3.8 4.1 4.4 v hys teresis 0.1 0.45 0.6 v oscillator f osc free running frequency 250 300 350 khz d v osc ramp amplitude - 1.5 - v p - p reference voltage v ref reference voltage measured at fb pin - 0.8 - v accuracy t a = - 20~70 c - 2.0 - +2.0 % line regulation v cc =1 2 ~ 5v - 0.05 0.5 % error amplifier dc gain - 86 - db f p1 first pole frequency - 0.4 - hz f z zero frequency - 0.4 - khz f p2 second pole frequency - 430 - khz average ugate duty range 0 - 70 % fb input current - - 0.1 m a pwm controller gate drivers ugate source v boot - phase =12v, v ugate - phase =6v 1.0 2 .0 - a ugate sink v boot - phase =12v, v ugate - phase =1v - 3.5 7 w lgate source v cc =12v, v lgate =6v 1.0 1. 9 - a lgate sink v cc =12v, v lgate =1v - 2. 6 5 w t d dead - time guaranteed by design - 40 100 ns n o t e 3 : p l e a s e r e f e r t o t h e t y p i c a l a p p l i c a t i o n c i r c u i t .
c o p y r i g h t ? a n p e c e l e c t r o n i c s c o r p . r e v . a . 3 - n o v . , 2 0 0 9 a p w 7 1 2 0 a w w w . a n p e c . c o m . t w 4 apw7120 a symbol parameter test conditions min . typ . max . unit protections i ocset ocse t current source v phase =0v, normal operation 35 40 45 m a over - current reference voltage t a = - 20~70 c 0.37 0.4 0.43 v u vfb fb under - voltage threshold v fb falling 62 67 72 % fb under - voltage hysteresis - 45 - mv over - voltage threshold v fb rising 114 118 122 % soft - start and shutdown t ss soft - start interval 2 3. 8 5 ms ocse t shutdown threshold falling v ocset 0.1 0.15 0.3 v ocse t shutdown hysteresis - 40 - mv e l e c t r i c a l c h a r a c t e r i s t i c s ( c o n t . ) u n l e s s o t h e r s w i s e s p e c i f i e d , t h e s e s p e c i f i c a t i o n s a p p l y o v e r v c c = 1 2 v , v b o o t = 1 2 v a n d t a = - 2 0 ~ 7 0 o c . t y p i c a l v a l u e s a r e a t t a = 2 5 o c .
c o p y r i g h t ? a n p e c e l e c t r o n i c s c o r p . r e v . a . 3 - n o v . , 2 0 0 9 a p w 7 1 2 0 a w w w . a n p e c . c o m . t w 5 t y p i c a l o p e r a t i n g c h a r a c t e r i s t i c s j u n c t i o n t e m p e r a t u r e ( o c ) r e f e r e n c e v o l t a g e v s . j u n c t i o n t e m p e r a t u r e reference voltage, v ref (v) s w i t c h i n g f r e q u e n c y v s . j u n c t i o n t e m p e r a t u r e j u n c t i o n t e m p e r a t u r e ( o c ) switching frequency, f osc (khz) o c s e t c u r r e n t v s . j u n c t i o n t e m p e r a t u r e v c c p o r t h r e s h o l d v o l t a g e v s . j u n c t i o n t e m p e r a t u r e j u n c t i o n t e m p e r a t u r e ( o c ) ocset current, i ocset ( m a) j u n c t i o n t e m p e r a t u r e ( o c ) vcc por threshold voltage (v) -50 -25 0 25 50 75 100 125 150 0.788 0.790 0.792 0.794 0.796 0.798 0.800 0.802 0.804 0.806 0.808 0.810 0.812 -50 -25 0 25 50 75 100 125 150 250 260 270 280 290 300 310 320 330 340 350 -50 -25 0 25 50 75 100 125 150 35 36 37 38 39 40 41 42 43 44 45 -50 -25 0 25 50 75 100 125 150 3.4 3.5 3.6 3.7 3.8 3.9 4.0 4.1 4.2 4.3 4.4 rising v cc falling v cc j u n c t i o n t e m p e r a t u r e ( o c ) o c s e t s h u t d o w n t h r e s h o l d v o l t a g e v s . j u n c t i o n t e m p e r a t u r e ocset shutdown threshold voltage (v ) -50 -25 0 25 50 75 100 125 150 0.10 0.12 0.14 0.16 0.18 0.20 falling v ocset
c o p y r i g h t ? a n p e c e l e c t r o n i c s c o r p . r e v . a . 3 - n o v . , 2 0 0 9 a p w 7 1 2 0 a w w w . a n p e c . c o m . t w 6 o p e r a t i n g w a v e f o r m s ( r e f e r t o t h e t y p i c a l a p p l i c a t i o n c i r c u i t , v b a i s = v i n = + 1 2 v s u p p l i e d b y a n a t x p o w e r s u p p l y ) 1 . l o a d t r a n s i e n t r e s p o n s e : i o u t = 0 a - > 1 5 a - > 0 a - i o u t s l e w r a t e = 7 . 5 a / m s c h 1 : v o u t , 1 0 0 m v / d i v , a c , c h 2 : i o u t , 1 0 a / d i v c h 3 : v u g a t e , 2 0 v / d i v , d c t i m e : 5 m s / d i v b w = 2 0 m h z c h 1 : v o u t , 1 0 0 m v / d i v , a c , c h 2 : i o u t , 1 0 a / d i v c h 3 : v u g a t e , 2 0 v / d i v , d c t i m e : 4 0 m s / d i v b w = 2 0 m h z c h 1 : v o u t , 1 0 0 m v / d i v , a c , c h 2 : i o u t , 1 0 a / d i v c h 3 : v u g a t e , 2 0 v / d i v , d c t i m e : 5 m s / d i v b w = 2 0 m h z i o u t = 0 a - > 1 5 a i o u t = 0 a - > 1 5 a - > 0 a i o u t = 1 5 a - > 0 a 1 1 3 3 2 2 1 1 3 3 2 2 1 1 3 3 2 2 v out v ugate i out v ugate i out v out v out =1.8v v out i out 0a 15a v ugate 2 . u g a t e a n d l g a t e s w i t c h i n g w a v e f o r m s r i s i n g v u g a t e c h 1 : v u g a t e , 5 v / d i v , d c t i m e : 2 0 n s / d i v c h 2 : v l g a t e , 2 v / d i v , d c b w = 5 0 0 m h z f a l l i n g v u g a t e c h 1 : v u g a t e , 5 v / d i v , d c t i m e : 2 0 n s / d i v c h 2 : v l g a t e , 2 v / d i v , d c b w = 5 0 0 m h z v ugate 1,2 1,2 i out = 15a v lgate 1,2 1,2 v ugate v lgate
c o p y r i g h t ? a n p e c e l e c t r o n i c s c o r p . r e v . a . 3 - n o v . , 2 0 0 9 a p w 7 1 2 0 a w w w . a n p e c . c o m . t w 7 o p e r a t i n g w a v e f o r m s ( c o n t . ) 3 . p o w e r i n g o n / o f f p o w e r i n g o n p o w e r i n g o f f c h 1 : v c c , 2 v / d i v , d c c h 3 : i l , 1 0 a / d i v , d c b w = 2 0 m h z c h 2 : v o u t , 1 v / d i v , d c t i m e : 1 0 m s / d i v 2 2 v cc i l v out 2 2 v cc i l v out ( r e f e r t o t h e t y p i c a l a p p l i c a t i o n c i r c u i t , v b i a s = v i n = + 1 2 v s u p p l i e d b y a n a t x p o w e r s u p p l y ) v cc =v in =5v r l =0.12 w 1 1 3 3 v cc =v in =5v r l =0.12 w 1 1 3 3 ch1 : v cc , 2v/div, dc ch3 : i l , 10a/div, dc bw = 20 mhz ch2 : v out , 1v/div, dc time : 5ms /div p o w e r i n g o n p o w e r i n g o f f 2 2 v cc i l v out 2 2 v cc i l v out 1 1 3 3 1 1 3 3 v cc =v in =12v r l =0.12 w v cc =v in =12v r l =0.12 w ch1 : v cc , 5v/div, dc ch3 : i l , 10a/div, dc bw = 20 mhz ch2 : v out , 1v/div, dc time : 5ms /div ch1 : v cc , 5v/div, dc ch3 : i l , 10a/div, dc bw = 20 mhz ch2 : v out , 1v/div, dc time : 10ms /div
c o p y r i g h t ? a n p e c e l e c t r o n i c s c o r p . r e v . a . 3 - n o v . , 2 0 0 9 a p w 7 1 2 0 a w w w . a n p e c . c o m . t w 8 4 . e n a b l i n g a n d s h u t t i n g d o w n e n a b l i n g b y r e l e a s i n g o c s e t p i n c h 1 : v o u t , 1 v / d i v , d c c h 3 : v o c s e t , 2 v / d i v , d c b w = 2 0 m h z c h 2 : v u g a t e , 2 0 v / d i v , d c t i m e : 2 m s / d i v s h u t t i n g d o w n b y p u l l i n g o c s e t l o w c h 1 : v o u t , 1 v / d i v , d c c h 3 : v o c s e t , 2 v / d i v , d c b w = 2 0 m h z c h 2 : v u g a t e , 2 0 v / d i v , d c t i m e : 2 m s / d i v 1 1 3 3 2 2 v out v ugate v ocset i out =2a v out v ugate v ocset 1 1 3 3 2 2 o p e r a t i n g w a v e f o r m s ( c o n t . ) ( r e f e r t o t h e t y p i c a l a p p l i c a t i o n c i r c u i t , v b i a s = v i n = + 1 2 v s u p p l i e d b y a n a t x p o w e r s u p p l y ) 5 . o v e r - c u r r e n t p r o t e c t i o n n o c o n n e c t i n g a s h u t d o w n m o s f e t a t o c s e t p i n c h 1 : v o u t , 1 v / d i v , d c t i m e : 5 m s / d i v c h 2 : i l , 1 0 a / d i v , d c b w = 2 0 m h z c o n n e c t i n g a s h u t d o w n m o s f e t ( 2 n 7 0 0 2 ) a t o c s e t p i n c h 1 : v o u t , 1 v / d i v , d c t i m e : 5 m s / d i v c h 2 : i l , 1 0 a / d i v , d c b w = 2 0 m h z i l 1 1 2 2 v out i l 1 1 2 2 v out r ocset =15k apm2512 r ocset =15k apm2512
c o p y r i g h t ? a n p e c e l e c t r o n i c s c o r p . r e v . a . 3 - n o v . , 2 0 0 9 a p w 7 1 2 0 a w w w . a n p e c . c o m . t w 9 6 . o c s e t v o l t a g e r c d e l a y c h 1 : v o c s e t , 0 . 5 v / d i v , d c t i m e : 2 m s / d i v c h 2 : i l , 1 0 a / d i v , d c b w = 2 0 m h z c h 1 : v o c s e t , 0 . 5 v / d i v , d c t i m e : 2 m s / d i v c h 2 : i l , 1 0 a / d i v , d c b w = 2 0 m h z v ocset i l c prober =8pf ocp ocp 1,2 1,2 i l ocp ocp 1,2 1,2 v ocset n o c o n n e c t i n g a s h u t d o w n m o s f e t a t o c s e t p i n c o n n e c t i n g a s h u t d o w n m o s f e t ( 2 n 7 0 0 2 ) a t o c s e t p i n c prober =8pf c 2n7002 =44pf (measured) o p e r a t i n g w a v e f o r m s ( c o n t . ) ( r e f e r t o t h e t y p i c a l a p p l i c a t i o n c i r c u i t , v b i a s = v i n = + 1 2 v s u p p l i e d b y a n a t x p o w e r s u p p l y ) 7 . s h o r t - c i r c u i t t e s t c h 1 : v o u t , 1 v / d i v , d c t i m e : 5 m s / d i v c h 2 : i l , 1 0 a / d i v , d c b w = 2 0 m h z 1 1 2 2 v out i l uvp ocp ocp ocp ocp shorted by a wire 6 . o c s e t v o l t a g e r c d e l a y c h 1 : v o c s e t , 0 . 5 v / d i v , d c t i m e : 2 m s / d i v c h 2 : i l , 1 0 a / d i v , d c b w = 2 0 m h z i l v ocset ocp ocp 1,2 1,2 c o n n e c t i n g a s h u t d o w n m o s f e t ( a p m 2 3 2 2 ) a t o c s e t p i n c prober =8pf c apm2322 =89pf (measured)
c o p y r i g h t ? a n p e c e l e c t r o n i c s c o r p . r e v . a . 3 - n o v . , 2 0 0 9 a p w 7 1 2 0 a w w w . a n p e c . c o m . t w 1 0 p i n d e s c r i p t i o n pin no. name function 1 boot this pin provides ground referenced bias voltage to the high - side mosfet driver. a bootstrap circuit with a diode connected to 5~12v is used to create a voltage suitable to drive a logic - level n - channel mosfet. 2 ugate conn ect this pin to the high - side n - channel mosfet gate. this pin provides gate drive for the high - side mosfet. 3 gnd the gnd terminal provides return path for the ic bias current and the low - side mosfet driver pull - low current. connect the pin to the system ground via very low impedance layout on pcbs. 4 lgate connect this pin to the low - side n - channel mosfet gate. this pin provides gate drive for the low - side mosfet. 5 vcc connect this pin to a 5~12v supply voltage. this pin provides bias supply for the co ntrol circuitry and the low - side mosfet driver. the voltage at this pin is monitored for the power - on - reset (por) purpose. 6 fb this pin is the inverting input of the internal gm amplifier. connect this pin to the output (v out ) of the converter via an ext ernal resistor divider for closed - loop operation. the output voltage set by the resistor divider is determined using the following formula: (v) ) r2 r1 1 ( 0.8v v out + = where r1 is the resistor connected from v out to fb , and r2 is the resistor connected from f b to gnd. the fb pin is also monitored for under and over - voltage events. 7 ocset the ocset is a dual - function input pin for over - current protection and shutdown control. connect a resistor (r ocset ) from this pin to the drain of the low - side mosfet. this resistor, an internal 40 m a current source (i ocset ), and the mosfet on - resistance ( r dson ) set the converter over - current trip level (i peak ) according to the following formula: (a) r 0.4v - r a 40 i dson ocset peak = pulling and holding this pin below 0.15v with an open dra in device, with very low parasitic capacitor, shuts down the ic with floating output and also resets the over - current counter. releasing ocset pin initiates a new soft - start and the converter works again. 8 phase the pin provides return path for the high - side mosfet driver pull - low current. connect this pin to the high - side mosfet source.
c o p y r i g h t ? a n p e c e l e c t r o n i c s c o r p . r e v . a . 3 - n o v . , 2 0 0 9 a p w 7 1 2 0 a w w w . a n p e c . c o m . t w 1 1 b l o c k d i a g r a m t y p i c a l a p p l i c a t i o n c i r c u i t c 3 , c 4 : 8 2 0 m f / 1 6 v , e s r = 2 5 m w c 6 , c 7 : 1 0 0 0 m f / 6 . 3 v , e s r = 3 0 m w vcc power-on- reset vcc ocset ugate lgate oscillator gate control v ref 0.8v soft-start and fault logic f osc 300khz phase gm amplifier fb pwm inhibit 40 m a comp 67%v ref uv gnd por soft-start oc boot regulator 3vcc ov 118%v ref 3vcc 0.4v 0.15v enable 2.5v v in +5/12v v out 1.8v/15a c5 1 m f c3, c4 820 m f x2 c6, c7 1000 m f x2 l2 1.5 m h q1 apm2512 ugate lgate 4 boot 1 gnd 3 vcc 5 phase 8 q2 apm2512 c1 1 m f 2 u1 apw7120a fb 6 ocset 7 r2 1.2k c2 0.1 m f q3 2n7002 shutdown r4 2.2 l1 1 m h r5 +5v/12v c8 0.1 m f r1 1.5k r3 200 d1 1n4148 v bias
c o p y r i g h t ? a n p e c e l e c t r o n i c s c o r p . r e v . a . 3 - n o v . , 2 0 0 9 a p w 7 1 2 0 a w w w . a n p e c . c o m . t w 1 2 f u n c t i o n d e s c r i p t i o n p o w e r - o n - r e s e t ( p o r ) t h e a p w 7 1 2 0 a m o n i t o r s t h e v c c v o l t a g e ( v c c ) f o r p o w e r - o n - r e s e t f u n c t i o n , p r e v e n t i n g w r o n g l o g i c o p e r a t i o n d u r - i n g p o w e r i n g o n . w h e n t h e v c c v o l t a g e i s r e a d y , t h e a p w 7 1 2 0 a s t a r t s a s t a r t - u p p r o c e s s a n d t h e n r a m p s t h e o u t p u t v o l t a g e u p t o t h e t a r g e t v o l t a g e . s o f t - s t a r t t h e a p w 7 1 2 0 a h a s a b u i l t - i n d i g i t a l s o f t - s t a r t t o c o n t r o l t h e o u t p u t v o l t a g e r i s e a n d l i m i t t h e c u r r e n t s u r g e a t t h e s t a r t - u p . d u r i n g s o f t - s t a r t , a n i n t e r n a l r a m p c o n n e c t e d t o t h e o n e o f t h e p o s i t i v e i n p u t s o f t h e g m a m p l i f i e r r i s e s u p f r o m 0 v t o 2 v t o r e p l a c e t h e r e f e r e n c e v o l t a g e ( 0 . 8 v ) u n t i l t h e r a m p v o l t a g e r e a c h e s t h e r e f e r e n c e v o l t a g e . t h e s o f t - s t a r t i n t e r v a l i s a b o u t 3 . 2 m s t y p i c a l , i n d e p e n d e n t o f t h e c o n v e r t e r ? s i n p u t a n d o u t p u t v o l t a g e s . o v e r - c u r r e n t p r o t e c t i o n ( o c p ) t h e o v e r - c u r r e n t f u n c t i o n p r o t e c t s t h e s w i t c h i n g c o n v e r t e r a g a i n s t o v e r - c u r r e n t o r s h o r t - c i r c u i t c o n d i t i o n s . t h e c o n - t r o l l e r s e n s e s t h e i n d u c t o r c u r r e n t b y d e t e c t i n g t h e d r a i n - t o - s o u r c e v o l t a g e , p r o d u c t o f t h e i n d u c t o r ? s c u r r e n t a n d t h e o n - r e s i s t a n c e , o f t h e l o w - s i d e m o s f e t d u r i n g i t ? s o n - s t a t e . t h i s m e t h o d e n h a n c e s t h e c o n v e r t e r ? s e f f i c i e n c y a n d r e d u c e s c o s t b y e l i m i n a t i n g a c u r r e n t s e n s i n g r e s i s t o r . a r e s i s t o r ( r o c s e t ) , c o n n e c t e d f r o m t h e o c s e t t o t h e l o w - s i d e m o s f e t ? s d r a i n , p r o g r a m s t h e o v e r - c u r r e n t t r i p l e v e l . a n i n t e r n a l 4 0 m a ( t y p i c a l ) c u r r e n t s o u r c e f l o w i n g t h r o u g h t h e r o c s e t d e v e l o p s a v o l t a g e ( v r o c s e t ) a c r o s s t h e r o c s e t . w h e n t h e v o c s e t ( v r o c s e t + v d s o f t h e l o w - s i d e m o s f e t ) i s l e s s t h a n t h e i n t e r n a l o v e r - c u r r e n t r e f e r e n c e v o l t a g e ( 0 . 4 v , t y p i c a l ) , t h e i c s h u t s o f f t h e c o n v e r t e r a n d t h e n i n i - t i a t e s a n e w s o f t - s t a r t p r o c e s s . a f t e r 4 o v e r - c u r r e n t e v e n t s a r e c o u n t e d , t h e d e v i c e t u r n s o f f b o t h h i g h - s i d e a n d l o w - s i d e m o s f e t s a n d t h e c o n v e r t e r ? s o u t p u t i s l a t c h e d t o b e f l o a t i n g . p l e a s e p a y a t t e n t i o n t o t h e r c d e l a y e f f e c t . i t c a u s e s t h e o c p t r i p l e v e l t o b e t h e f u n c t i o n o f t h e o p e r a t i n g d u t y . t h e p a r a s i t i c c a p a c i t a n c e ( i n c l u d i n g t h e c a p a c i t a n c e i n s i d e t h e o c s e t , e x t e r n a l p c b t r a c e c a p a c i t a n c e a n d t h e c o s s o f t h e s h u t d o w n m o s f e t ) m u s t b e m i n i m i z e d , e s p e c i a l l y s e l e c t i n g a s h u t d o w n m o s f e t w i t h v e r y s m a l l c o s s . t h e o c p t r i p l e v e l f o l l o w s t h e d u t y t o i n c r e a s e a l i t t l e a t l o w o p e r a t i n g d u t y , b u t v e r y m u c h a t h i g h o p e r a t i n g d u t y , l i k e t h e r c d e l a y c u r v e . d u e t o l o a d r e g u l a t i o n o r c u r r e n t - l i m i t , h e a v y l o a d n o r m a l l y r e d u c e s c o n v e r t e r ? s i n p u t v o l t a g e a n d i n c r e a s e s t h e p o w e r l o s e s . d u r i n g h e a v y l o a d , t h e a p w 7 1 2 0 a r e g u l a t e s t h e o u t p u t v o l t a g e b y e x - p e n d i n g t h e d u t y . t h i s r i s e s u p t h e o c p t r i p l e v e l a t t h e s a m e t i m e . u n d e r - v o l t a g e p r o t e c t i o n ( u v p ) t h e u n d e r - v o l t a g e f u n c t i o n m o n i t o r s t h e f b v o l t a g e ( v f b ) t o p r o t e c t t h e c o n v e r t e r a g a i n s t s h o r t - c i r c u i t c o n d i t i o n s . w h e n t h e v f b f a l l s b e l o w t h e f a l l i n g u v p t h r e s h o l d ( 6 7 % v r e f ) , t h e a p w 7 1 2 0 a s h u t s o f f t h e c o n v e r t e r . a f t e r a p r e - c e d i n g d e l a y , w h i c h s t a r t s a t t h e b e g i n n i n g o f t h e u n d e r - v o l t a g e s h u t d o w n , t h e a p w 7 1 2 0 a i n i t i a t e s a n e w s o f t - s t a r t t o r e s u m e r e g u l a t i n g . t h e u n d e r - v o l t a g e p r o t e c t i o n s h u t s o f f a n d t h e n r e - s t a r t s t h e c o n v e r t e r r e p e a t e d l y w i t h - o u t l a t c h i n g . t h e f u n c t i o n i s d i s a b l e d d u r i n g s o f t - s t a r t p r o c e s s . o v e r - v o l t a g e p r o t e c t i o n ( o v p ) t h e o v e r - v o l t a g e p r o t e c t i o n m o n i t o r s t h e f b v o l t a g e t o p r e v e n t t h e o u t p u t f r o m o v e r - v o l t a g e . w h e n t h e o u t p u t v o l t a g e r i s e s t o 1 1 8 % o f t h e n o m i n a l o u t p u t v o l t a g e , t h e a p w 7 1 2 0 a t u r n s o n t h e l o w - s i d e m o s f e t u n t i l t h e o u t - p u t v o l t a g e f a l l s b e l o w t h e o v p t h r e s h o l d , r e g u l a t i n g t h e o u t p u t v o l t a g e a r o u n d t h e o v p t h r e s h o l d s . a d a p t i v e s h o o t - t h r o u g h p r o t e c t i o n t h e g a t e d r i v e r i n c o r p o r a t e s a d a p t i v e s h o o t - t h r o u g h p r o - t e c t i o n t o h i g h - s i d e a n d l o w - s i d e m o s f e t s f r o m c o n - d u c t i n g s i m u l t a n e o u s l y a n d s h o r t i n g t h e i n p u t s u p p l y . t h i s i s a c c o m p l i s h e d b y e n s u r i n g t h e f a l l i n g g a t e h a s t u r n e d o f f o n e m o s f e t b e f o r e t h e o t h e r i s a l l o w e d t o r i s e . d u r i n g t u r n - o f f o f t h e l o w - s i d e m o s f e t , t h e l g a t e v o l t - a g e i s m o n i t o r e d u n t i l i t r e a c h e s a 1 . 5 v t h r e s h o l d , a t w h i c h t i m e t h e u g a t e i s r e l e a s e d t o r i s e a f t e r a c o n s t a n t d e l a y . d u r i n g t u r n - o f f o f t h e h i g h - s i d e m o s f e t , t h e u g a t e - t o - p h a s e v o l t a g e i s a l s o m o n i t o r e d u n t i l i t r e a c h e s a 1 . 5 v t h r e s h o l d , a t w h i c h t i m e t h e l g a t e i s r e l e a s e d t o r i s e a f t e r a c o n s t a n t d e l a y .
c o p y r i g h t ? a n p e c e l e c t r o n i c s c o r p . r e v . a . 3 - n o v . , 2 0 0 9 a p w 7 1 2 0 a w w w . a n p e c . c o m . t w 1 3 f u n c t i o n d e s c r i p t i o n ( c o n t . ) s h u t d o w n c o n t r o l p u l l i n g t h e o c s e t v o l t a g e b e l o w 0 . 1 5 v b y a n o p e n d r a i n t r a n s i s t o r , s h o w n i n t y p i c a l a p p l i c a t i o n c i r c u i t , s h u t s d o w n t h e a p w 7 1 2 0 a p w m c o n t r o l l e r . i n s h u t d o w n m o d e , t h e u g a t e a n d l g a t e a r e p u l l e d t o p h a s e a n d g n d r e s p e c t i v e l y , t h e o u t p u t i s f l o a t i n g .
c o p y r i g h t ? a n p e c e l e c t r o n i c s c o r p . r e v . a . 3 - n o v . , 2 0 0 9 a p w 7 1 2 0 a w w w . a n p e c . c o m . t w 1 4 a p p l i c a t i o n i n f o r m a t i o n f o r a t h r o u g h h o l e d e s i g n , s e v e r a l e l e c t r o l y t i c c a p a c i t o r s m a y b e n e e d e d . f o r s u r f a c e m o u n t d e s i g n s , s o l i d t a n t a - l u m c a p a c i t o r s c a n b e u s e d , b u t c a u t i o n m u s t b e e x e r - c i s e d w i t h r e g a r d t o t h e c a p a c i t o r s u r g e c u r r e n t r a t i n g . i n p u t c a p a c i t o r s e l e c t i o n u s e s m a l l c e r a m i c c a p a c i t o r s f o r h i g h f r e q u e n c y d e c o u p l i n g a n d b u l k c a p a c i t o r s t o s u p p l y t h e s u r g e c u r - r e n t n e e d e d e a c h t i m e h i g h - s i d e m o s f e t ( q 1 ) t u r n s o n . p l a c e t h e s m a l l c e r a m i c c a p a c i t o r s p h y s i c a l l y c l o s e t o t h e m o s f e t s a n d b e t w e e n t h e d r a i n o f q 1 a n d t h e s o u r c e o f l o w - s i d e m o s f e t ( q 2 ) . t h e i m p o r t a n t p a r a m e t e r s f o r t h e b u l k i n p u t c a p a c i t o r a r e t h e v o l t a g e r a t i n g a n d t h e r m s c u r r e n t r a t i n g . f o r r e l i a b l e o p e r a t i o n , s e l e c t t h e b u l k c a p a c i t o r w i t h v o l t a g e a n d c u r - r e n t r a t i n g s a b o v e t h e m a x i m u m i n p u t v o l t a g e a n d l a r g - e s t r m s c u r r e n t r e q u i r e d b y t h e c i r c u i t . t h e c a p a c i t o r v o l t - a g e r a t i n g s h o u l d b e a t l e a s t 1 . 2 5 t i m e s g r e a t e r t h a n t h e m a x i m u m i n p u t v o l t a g e a n d a v o l t a g e r a t i n g o f 1 . 5 t i m e s i s a c o n s e r v a t i v e g u i d e l i n e . t h e r m s c u r r e n t o f t h e b u l k i n p u t c a p a c i t o r i s c a l c u l a t e d a s t h e f o l l o w i n g e q u a t i o n : v in v out c in c out l q1 ugate q2 lgate esr i l i out i q1 i cout i out v ugate t=1/f osc i l i q1 i cout i out i i v out dt v out f i g u r e 1 . b u c k c o n v e r t e r w a v e f o r m s o u t p u t c a p a c i t o r s e l e c t i o n a n o u t p u t c a p a c i t o r i s r e q u i r e d t o f i l t e r t h e o u t p u t a n d s u p - p l y t h e l o a d t r a n s i e n t c u r r e n t . t h e f i l t e r i n g r e q u i r e m e n t s a r e a f u n c t i o n o f t h e s w i t c h i n g f r e q u e n c y a n d t h e r i p p l e c u r r e n t . t h e o u t p u t r i p p l e i s t h e s u m o f t h e v o l t a g e s , h a v - i n g p h a s e s h i f t , a c r o s s t h e e s r a n d t h e i d e a l o u t p u t c a p a c i t o r . t h e p e a k - t o - p e a k v o l t a g e o f t h e e s r i s c a l c u - l a t e d a s t h e f o l l o w i n g e q u a t i o n s : ..(3) .......... (v) esr i v .(2) .......... (a) l f d) - (1 v i (1) . .......... (v) v d v esr osc out in out d = = d = t h e p e a k - t o - p e a k v o l t a g e o f t h e i d e a l o u t p u t c a p a c i t o r i s c a l c u l a t e d a s t h e f o l l o w i n g e q u a t i o n : (4) ....... (v) c f 8 i v out osc cout d = d f o r g e n e r a l a p p l i c a t i o n s u s i n g b u l k c a p a c i t o r s , t h e d v c o u t i s m u c h s m a l l e r t h a n t h e v e s r a n d c a n b e i g n o r e d . t h e r e f o r e , t h e a c p e a k - t o - p e a k o u t p u t v o l t a g e i s s h o w n b e l o w : .(5) .......... (v) esr i v out d = d t h e l o a d t r a n s i e n t r e q u i r e m e n t s a r e t h e f u n c t i o n o f t h e s l e w r a t e ( d i / d t ) a n d t h e m a g n i t u d e o f t h e t r a n s i e n t l o a d c u r r e n t . t h e s e r e q u i r e m e n t s a r e g e n e r a l l y m e t w i t h a m i x o f c a p a c i t o r s a n d c a r e f u l l a y o u t . m o d e r n c o m p o n e n t s a n d l o a d s a r e c a p a b l e o f p r o d u c i n g t r a n s i e n t l o a d r a t e s (a) d) - (1 d i i out rms =
c o p y r i g h t ? a n p e c e l e c t r o n i c s c o r p . r e v . a . 3 - n o v . , 2 0 0 9 a p w 7 1 2 0 a w w w . a n p e c . c o m . t w 1 5 a p p l i c a t i o n i n f o r m a t i o n ( c o n t . ) o u t p u t c a p a c i t o r s e l e c t i o n ( c o n t . ) t h e r e s p o n s e t i m e t o a t r a n s i e n t i s d i f f e r e n t f o r t h e a p p l i - c a t i o n o f l o a d a n d t h e r e m o v a l o f l o a d . t h e f o l l o w i n g e q u a - a b o v e 1 a / n s . h i g h f r e q u e n c y c a p a c i t o r s i n i t i a l l y s u p p l y t h e t r a n s i e n t a n d s l o w t h e c u r r e n t l o a d r a t e s e e n b y t h e b u l k c a p a c i t o r s . t h e b u l k f i l t e r c a p a c i t o r v a l u e s a r e g e n e r - a l l y d e t e r m i n e d b y t h e e s r ( e f f e c t i v e s e r i e s r e s i s t a n c e ) a n d v o l t a g e r a t i n g r e q u i r e m e n t s r a t h e r t h a n a c t u a l c a - p a c i t a n c e r e q u i r e m e n t s . h i g h f r e q u e n c y d e c o u p l i n g c a p a c i t o r s s h o u l d b e p l a c e d a s c l o s e t o t h e p o w e r p i n s o f t h e l o a d a s p h y s i c a l l y p o s s i b l e . b e c a r e f u l n o t t o a d d i n d u c t a n c e i n t h e c i r c u i t b o a r d w i r i n g t h a t c o u l d c a n c e l t h e u s e f u l n e s s o f t h e s e l o w i n d u c t a n c e c o m p o n e n t s . a n a l u m i n u m e l e c t r o l y t i c c a p a c i t o r ? s e s r v a l u e i s r e l a t e d t o t h e c a s e s i z e w i t h l o w e r e s r a v a i l a b l e i n l a r g e r c a s e s i z e s . h o w e v e r , t h e e q u i v a l e n t s e r i e s i n d u c t a n c e ( e s l ) o f t h e s e c a p a c i t o r s i n c r e a s e s w i t h c a s e s i z e a n d c a n r e - d u c e t h e u s e f u l n e s s o f t h e c a p a c i t o r t o h i g h s l e w - r a t e t r a n s i e n t l o a d i n g . i n m o s t c a s e s , m u l t i p l e e l e c t r o l y t i c c a - p a c i t o r s o f s m a l l c a s e s i z e p e r f o r m b e t t e r t h a n a s i n g l e l a r g e c a s e c a p a c i t o r . o u t p u t i n d u c t o r s e l e c t i o n t h e o u t p u t i n d u c t o r i s s e l e c t e d t o m e e t t h e o u t p u t v o l t a g e r i p p l e r e q u i r e m e n t s a n d m i n i m i z e t h e c o n v e r t e r ? s r e - s p o n s e t i m e t o t h e l o a d t r a n s i e n t . t h e i n d u c t o r v a l u e d e - t e r m i n e s t h e c o n v e r t e r ? s r i p p l e c u r r e n t a n d t h e r i p p l e v o l t a g e , s e e e q u a t i o n s ( 2 ) a n d ( 5 ) . i n c r e a s i n g t h e v a l u e o f i n d u c t a n c e r e d u c e s t h e r i p p l e c u r r e n t a n d v o l t a g e . h o w e v e r , t h e l a r g e i n d u c t a n c e v a l u e s r e d u c e t h e c o n v e r t e r ? s r e s p o n s e t i m e t o a l o a d t r a n s i e n t . o n e o f t h e p a r a m e t e r s l i m i t i n g t h e c o n v e r t e r ? s r e s p o n s e t o a l o a d t r a n s i e n t i s t h e t i m e r e q u i r e d t o c h a n g e t h e i n - d u c t o r c u r r e n t . g i v e n a s u f f i c i e n t l y f a s t c o n t r o l l o o p d e s i g n , t h e a p w 7 1 2 0 a w i l l p r o v i d e e i t h e r 0 % o r 8 5 % ( a v e r a g e ) d u t y c y c l e i n r e s p o n s e t o a l o a d t r a n s i e n t . t h e r e s p o n s e t i m e i s t h e t i m e r e q u i r e d t o s l e w t h e i n d u c t o r c u r r e n t f r o m a n i n i t i a l c u r r e n t v a l u e t o t h e t r a n s i e n t c u r r e n t l e v e l . d u r - i n g t h i s i n t e r v a l t h e d i f f e r e n c e b e t w e e n t h e i n d u c t o r c u r - r e n t a n d t h e t r a n s i e n t c u r r e n t l e v e l m u s t b e s u p p l i e d b y t h e o u t p u t c a p a c i t o r . m i n i m i z i n g t h e r e s p o n s e t i m e c a n m i n i m i z e t h e o u t p u t c a p a c i t a n c e r e q u i r e d . v i l t , v v i l t out tran fall out in tran rise = - = w h e r e i t r a n i s t h e t r a n s i e n t l o a d c u r r e n t s t e p , t r i s e i s t h e r e s p o n s e t i m e t o t h e a p p l i c a t i o n o f l o a d , a n d t f a l l i s t h e r e s p o n s e t i m e t o t h e r e m o v a l o f l o a d . t h e w o r s t c a s e r e s p o n s e t i m e c a n b e e i t h e r a t t h e a p p l i c a t i o n o r r e m o v a l o f l o a d . b e s u r e t o c h e c k b o t h o f t h e s e e q u a t i o n s a t t h e t r a n s i e n t l o a d c u r r e n t . t h e s e r e q u i r e m e n t s a r e m i n i m u m a n d m a x i m u m o u t p u t l e v e l s f o r t h e w o r s t c a s e r e s p o n s e t i m e . m o s f e t s e l e c t i o n i n h i g h - c u r r e n t a p p l i c a t i o n s , t h e m o s f e t p o w e r d i s s i p a t i o n , p a c k a g e s e l e c t i o n a n d h e a t s i n k a r e t h e d o m i - n a n t d e s i g n f a c t o r s . t h e p o w e r d i s s i p a t i o n i n c l u d e s t w o l o s s c o m p o n e n t s , c o n d u c t i o n l o s s a n d s w i t c h i n g l o s s . t h e c o n d u c t i o n l o s s e s a r e t h e l a r g e s t c o m p o n e n t o f p o w e r d i s s i p a t i o n f o r b o t h t h e h i g h - s i d e a n d t h e l o w - s i d e m o s f e t s . t h e s e l o s s e s a r e d i s t r i b u t e d b e t w e e n t h e t w o m o s f e t s a c c o r d i n g t o d u t y f a c t o r ( s e e t h e e q u a t i o n s b e l o w ) . o n l y t h e h i g h - s i d e m o s f e t h a s s w i t c h i n g l o s s e s , s i n c e t h e l o w - s i d e m o s f e t s b o d y d i o d e o r a n e x t e r n a l s c h o t t k y r e c t i f i e r a c r o s s t h e l o w e r m o s f e t c l a m p s t h e s w i t c h i n g n o d e b e f o r e t h e s y n c h r o n o u s r e c t i f i e r t u r n s o n . t h e s e e q u a t i o n s a s s u m e l i n e a r v o l t a g e - c u r r e n t t r a n s i - t i o n s a n d d o n o t a d e q u a t e l y m o d e l p o w e r l o s s d u e t h e r e v e r s e - r e c o v e r y o f t h e l o w - s i d e m o s f e t ? s b o d y d i o d e . t h e g a t e - c h a r g e l o s s e s a r e d i s s i p a t e d b y t h e a p w 7 1 2 0 a a n d d o n ? t h e a t t h e m o s f e t s . h o w e v e r , l a r g e g a t e - c h a r g e i n c r e a s e s t h e s w i t c h i n g i n t e r v a l , t s w w h i c h i n c r e a s e s t h e h i g h - s i d e m o s f e t s w i t c h i n g l o s s e s . e n s u r e t h a t b o t h m o s f e t s a r e w i t h i n t h e i r m a x i m u m j u n c t i o n t e m p e r a - t u r e a t h i g h a m b i e n t t e m p e r a t u r e b y c a l c u l a t i n g t h e t e m - p e r a t u r e r i s e a c c o r d i n g t o p a c k a g e t h e r m a l - r e s i s t a n c e s p e c i f i c a t i o n s . a s e p a r a t e h e a t s i n k m a y b e n e c e s s a r y d e p e n d i n g u p o n m o s f e t p o w e r , p a c k a g e t y p e , a m b i e n t t e m p e r a t u r e a n d a i r f l o w . d) - (1 r i p f t v i 2 1 d r i p dson 2 out side - low osc sw in out dson 2 out side - high = + = t i o n s g i v e t h e a p p r o x i m a t e r e s p o n s e t i m e i n t e r v a l f o r a p - p l i c a t i o n a n d r e m o v a l o f a t r a n s i e n t l o a d : w h e r e t s w i s t h e s w i t c h i n g i n t e r v a l
c o p y r i g h t ? a n p e c e l e c t r o n i c s c o r p . r e v . a . 3 - n o v . , 2 0 0 9 a p w 7 1 2 0 a w w w . a n p e c . c o m . t w 1 6 a p p l i c a t i o n i n f o r m a t i o n ( c o n t . ) f e e d b a c k c o m p e n s a t i o n t h e f i g u r e 2 s h o w s t h e c o n t r o l s y s t e m o f t h e a p w 7 1 2 0 , w h i c h c o n s i s t s o f a n i n t e r n a l v o l t a g e - m o d e p w m m o d u l a t o r , a n o u t p u t l - c f i l t e r , a r e s i s t o r - d i v i d e r a n d a n i n t e r n a l c o m p e n s a t i o n n e t w o r k . t h e r a n d c a r e t h e e q u i v a l e n t s e r i e s r e s i s t a n c e ( e s r ) a n d c a p a c i t a n c e o f t h e o u t p u t c a p a c i t o r ; t h e l i s t h e i n d u c t a n c e o f t h e o u t p u t i n d u c t o r . f i g u r e 2 . a p w 7 1 2 0 c o n t r o l s y s t e m t h e t r a n s f e r f u n c t i o n s a r e d e f i n e d a s f o l l o w i n g : r2 r1 r2 (s) v (s) v a1(s) o fb + = = on) compensati (internal (s) v (s) v a2(s) fb comp = v v (s) v (s) v a3(s) osc in comp phase d = = 1 s c r s c l 1 s c r (s) v (s) v a4(s) 2 phase out + + + = = out cl o fbcompphaseout ofbcompphase v(s) a(s) v(s) v(s)v(s)v(s)v(s) v(s)v(s)v(s)v(s) a1(s)a2(s)a3(s)a4(s) = = = w h e r e a 1 ( s ) i s t h e t r a n s f e r f u n c t i o n o f t h e r e s i s t o r - d i v i d e r , a 2 ( s ) i s t h e t r a n s f e r f u n c t i o n o f t h e f e e d b a c k c o m p e n s a - t i o n n e t w o r k , a 3 ( s ) i s t h e t r a n s f e r f u n c t i o n o f t h e p w m m o d u l a t o r , a 4 ( s ) i s t h e t r a n s f e r f u n c t i o n o f t h e o u t p u t l c f i l t e r , a n d a c l ( s ) i s t h e t r a n s f e r f u n c t i o n o f t h e c l o s e d - l o o p c o n t r o l s y s t e m . r e f e r t o f i g u r e 3 . t h e p o l e a n d z e r o f r e - ) (f 0.4khz f z za21 = ) (f 430khz f p2 pa21 = lc x 2 1 f pa41,2 p = xrxc 2 1 f za41 p = r2 r1 v out apw7120 v fb r c 0.8v fb v o l v osc =1.6v driver v phase v in v comp internal compensation network ugate lgate where the f pa21 (or f p2 ) and f za21 (or f z ) are the pole and zero frequencies of the a2(s), the f pa41,2 and f za41 are the double-pole and zero frequencies of the a4(s), the v in is the input voltage of the pwm converter and the load resis- tance of the converter is very large. for good converter stability, the values of the l, c, and r must be selected to meet the following criteria: 1. make sure the double-pole frequency (f pa41,2 ) of the output filter is bigger than the zero frequency (f za21 ) of the internal compensation network. 2. the following equation must be true: 0 1.2 ) c l r 1 log( 2 ) r2 r1 r2 log( ) v v log( osc in > + - + + d 3 . t h e c o n v e r t e r c r o s s o v e r f r e q u e n c y ( f c o ) m u s t b e i n t h e r a n g e o f 1 0 % ~ 3 0 % o f m i n i m u m f o s c o f t h e c o n v e r t e r . t h e f c o i s c a l c u l a t e d b y u s i n g t h e f o l l o w i n g e q u a t i o n s : 7 2 ) c l r 1 log( 40 ) r2 r1 r2 log( 20 ) v v log( 20 f at gain osc in za41 + - + + d = osc_min za41 20 fza41 at gain co osc_min f 30% f 10 f f 10% ? ? ? ? ? = 4 . t h e v a l u e s o f l , c , a n d r s e l e c t e d m u s t m e e t t h e e q u a t i o n s a b o v e o v e r t h e o p e r a i n g t e m p e r a t u r e , v o l t a g e , a n d c u r r e n t r a n g e s . q u e n c i e s o f t h e a 1 ( s ) , a 2 ( s ) , a 3 ( s ) , a n d a c l ( s ) a r e s h o w n o r c a l c u l a t e d a s t h e f o l l o w i n g e q u a t i o n s :
c o p y r i g h t ? a n p e c e l e c t r o n i c s c o r p . r e v . a . 3 - n o v . , 2 0 0 9 a p w 7 1 2 0 a w w w . a n p e c . c o m . t w 1 7 a p p l i c a t i o n i n f o r m a t i o n ( c o n t . ) f e e d b a c k c o m p e n s a t i o n ( c o n t . ) l a y o u t c o n s i d e r a t i o n i n h i g h p o w e r s w i t c h i n g r e g u l a t o r , a c o r r e c t l a y o u t i s i m - p o r t a n t t o e n s u r e p r o p e r o p e r a t i o n o f t h e r e g u l a t o r . i n g e n e r a l , i n t e r c o n n e c t i n g i m p e d a n c e s s h o u l d b e m i n i - m i z e d b y u s i n g s h o r t , w i d e p r i n t e d c i r c u i t t r a c e s . s i g n a l a n d p o w e r g r o u n d s a r e t o b e k e p t s e p a r a t e a n d f i n a l l y c o m b i n e d u s i n g g r o u n d p l a n e c o n s t r u c t i o n o r s i n g l e p o i n t g r o u n d i n g . f i g u r e 4 i l l u s t r a t e s t h e l a y o u t , w i t h b o l d l i n e s i n d i c a t i n g h i g h c u r r e n t p a t h s . c o m p o n e n t s a l o n g t h e b o l d l i n e s s h o u l d b e p l a c e d c l o s e t o g e t h e r . b e l o w i s a c h e c k - l i s t f o r y o u r l a y o u t : 1 . b e g i n t h e l a y o u t b y p l a c i n g t h e p o w e r c o m p o n e n t s f i r s t . o r i e n t t h e p o w e r c i r c u i t r y t o c h i e v e a c l e a n p o w e r f l o w p a t h . i f p o s s i b l e , m a k e a l l t h e c o n n e c t i o n s o n o n e s i d e o f t h e p c b w i t h w i d e , c o p p e r f i l l e d a r e a s . 2 . c o n n e c t t h e g r o u n d o f f e e d b a c k d i v i d e r d i r e c t l y t o t h e g n d p i n o f t h e i c u s i n g a d e d i c a t e d g r o u n d t r a c e . 3 . t h e v c c d e c o u p l i n g c a p a c i t o r s h o u l d b e r i g h t n e x t t o t h e v c c a n d g n d p i n s . c a p a c i t o r c b o o t s h o u l d b e c o n - n e c t e d a s c l o s e t o t h e b o o t a n d p h a s e p i n s a s p o s s i b l e . 4 . m i n i m i z e t h e l e n g t h a n d i n c r e a s e t h e w i d t h o f t h e t r a c e b e t w e e n u g a t e / l g a t e a n d t h e g a t e s o f t h e m o s f e t s t o r e d u c e t h e i m p e d a n c e d r i v i n g t h e m o s f e t s . 5 . u s e a n d e d i c a t e d t r a c e t o c o n n e c t t h e r o c s e t a n d t h e d r a i n p a d o f t h e l o w - s i d e m o s f e t , k e v i n c o n n e c t i o n , f o r a c c u r a t e c u r r e n t s e n s i n g . f i g u r e 3 . c o n v e r t e r g a i n v s . f r e q u e n c y 6 . k e e p t h e s w i t c h i n g n o d e s ( u g a t e , l g a t e , a n d p h a s e ) a w a y f r o m s e n s i t i v e s m a l l s i g n a l n o d e s s i n c e t h e s e n o d e s a r e f a s t m o v i n g s i g n a l s . t h e r e f o r e , k e e p t r a c e s t o t h e s e n o d e s a s s h o r t a s p o s s i b l e . 7 . p l a c e t h e d e c o u p l i n g c e r a m i c c a p a c i t o r c h f n e a r t h e d r a i n o f t h e h i g h - s i d e m o s f e t a s c l o s e a s p o s s i b l e . t h e b u l k c a p a c i t o r s c i n a r e a l s o p l a c e d n e a r t h e d r a i n . 8 . p l a c e t h e s o u r c e o f t h e h i g h - s i d e m o s f e t a n d t h e d r a i n o f t h e l o w - s i d e m o s f e t a s c l o s e a s p o s s i b l e . m i n i m i z i n g t h e i m p e d a n c e w i t h w i d e l a y o u t p l a n e b e - t w e e n t h e t w o p a d s r e d u c e s t h e v o l t a g e b o u n c e o f t h e n o d e . 9 . u s e a w i d e p o w e r g r o u n d p l a n e , w i t h l o w i m p e d a n c e , t o c o n n e c t s t h e c h f , c i n , c o u t , s c h o t t k y d i o d e a n d t h e s o u r c e o f t h e l o w - s i d e m o s f e t t o p r o v i d e a l o w i m - p e d a n c e p a t h b e t w e e n t h e c o m p o n e n t s f o r l a r g e a n d h i g h f r e q u e n c y s w i t c h i n g c u r r e n t s . -60 -40 -20 0 20 40 60 80 100 100 1k 10k 100k 1m 10m compensation gain frequency (f, hz) g a i n ( d b ) f za21 f pa21 converter gain pwm &filter gain f co f za41 f pa41,2 v in v out q1 l1 4 8 2 u 1 1 5 c out c in + + apw7120a ugate lgate vcc phase boot c hf q2 f i g u r e 4 . r e c o m m e n d e d l a y o u t d i g r a m
c o p y r i g h t ? a n p e c e l e c t r o n i c s c o r p . r e v . a . 3 - n o v . , 2 0 0 9 a p w 7 1 2 0 a w w w . a n p e c . c o m . t w 1 8 p a c k a g e i n f o r m a t i o n s o p - 8 d e e e 1 see view a c b h x 4 5 a a 1 a 2 l view a 0 . 2 5 seating plane gauge plane note: 1. follow jedec ms-012 aa. 2. dimension ? d ? does not include mold flash, protrusions or gate burrs. mold flash, protrusion or gate burrs shall not exceed 6 mil per side. 3. dimension ? e ? does not include inter-lead flash or protrusions. inter-lead flash and protrusions shall not exceed 10 mil per side. s y m b o l min. max. 1.75 0.10 0.17 0.25 0.25 a a1 c d e e1 e h l millimeters b 0.31 0.51 sop-8 0.25 0.50 0.40 1.27 min. max. inches 0.069 0.004 0.012 0.020 0.007 0.010 0.010 0.020 0.016 0.050 0 0.010 1.27 bsc 0.050 bsc a2 1.25 0.049 0 8 0 8 3.80 5.80 4.80 4.00 6.20 5.00 0.189 0.197 0.228 0.244 0.150 0.157
c o p y r i g h t ? a n p e c e l e c t r o n i c s c o r p . r e v . a . 3 - n o v . , 2 0 0 9 a p w 7 1 2 0 a w w w . a n p e c . c o m . t w 1 9 c a r r i e r t a p e & r e e l d i m e n s i o n s h t1 a d a e 1 a b w f t p0 od0 b a0 p2 k0 b 0 section b-b section a-a od1 p1 application a h t1 c d d w e1 f 330.0 ? 2.00 50 min. 12.4+2.00 - 0.00 13.0+0.50 - 0.20 1.5 min. 20.2 min. 12.0 ? 0.30 1.75 ? 0.10 5.5 ? 0.05 p 0 p1 p 2 d 0 d1 t a 0 b 0 k 0 so p - 8 4.0 ? 0.10 8.0 ? 0.10 2.0 ? 0.05 1.5+0.10 - 0.00 1.5 min. 0.6+0.00 - 0.40 6.40 ? 0.20 5.20 ? 0.20 2.10 ? 0.20 (mm) package type unit quantity sop - 8 tape & reel 2500 d e v i c e s p e r u n i t
c o p y r i g h t ? a n p e c e l e c t r o n i c s c o r p . r e v . a . 3 - n o v . , 2 0 0 9 a p w 7 1 2 0 a w w w . a n p e c . c o m . t w 2 0 t a p i n g d i r e c t i o n i n f o r m a t i o n c l a s s i f i c a t i o n p r o f i l e s o p - 8 user direction of feed
c o p y r i g h t ? a n p e c e l e c t r o n i c s c o r p . r e v . a . 3 - n o v . , 2 0 0 9 a p w 7 1 2 0 a w w w . a n p e c . c o m . t w 2 1 c l a s s i f i c a t i o n r e f l o w p r o f i l e s profile feature sn - pb eutectic assembly pb - free assembly preheat & soak temperature min (t smin ) temperature max (t smax ) time (t smin to t smax ) ( t s ) 100 c 150 c 60 - 120 seconds 150 c 200 c 60 - 1 2 0 seconds average ramp - up rate (t smax to t p ) 3 c/second ma x. 3 c/second max. liquidous temperature ( t l ) time at l iquidous (t l ) 183 c 60 - 150 seconds 217 c 60 - 150 seconds peak package body temperature (t p ) * see classification temp in table 1 see classification temp in table 2 time (t p ) ** within 5 c of the spec ified c lassification t emperature ( t c ) 2 0 ** seconds 3 0 ** seconds average r amp - down rate (t p to t smax ) 6 c/second max. 6 c/second max. time 25 c to p eak t emperature 6 minutes max. 8 minutes max. * tolerance for peak profile temperature (t p ) is defined a s a supplier minimum and a user maximum. ** tolerance for time at peak profile temperature (t p ) is defined as a supplier minimum and a user maximum. table 2. pb - free process ? classification temperatures (tc) package thickness volume mm 3 <350 volume mm 3 350 - 2000 volume mm 3 >2000 <1.6 mm 260 c 260 c 260 c 1.6 mm ? 2.5 mm 260 c 250 c 245 c 3 2.5 mm 250 c 245 c 245 c table 1. snpb eutectic process ? classification temperatures (tc) package thickness volume mm 3 <350 volume mm 3 3 350 <2.5 mm 235 c 22 0 c 3 2.5 mm 220 c 220 c r e l i a b i l i t y t e s t p r o g r a m test item method description solderability jesd - 22, b102 5 sec, 245 c holt jesd - 22, a108 1000 hrs, bias @ 125 c pct jesd - 22, a102 168 hrs, 100 % rh, 2atm , 121 c tct jesd - 22, a104 500 cycles, - 65 c~150 c hbm mil - std - 883 - 3015.7 vhbm ? 2kv mm jesd - 22, a115 vmm ? 200v latch - up jesd 78 10ms, 1 tr ? 100ma
c o p y r i g h t ? a n p e c e l e c t r o n i c s c o r p . r e v . a . 3 - n o v . , 2 0 0 9 a p w 7 1 2 0 a w w w . a n p e c . c o m . t w 2 2 c u s t o m e r s e r v i c e a n p e c e l e c t r o n i c s c o r p . head office : no.6, dusing 1st road, sbip, hsin-chu, taiwan, r.o.c. tel : 886-3-5642000 fax : 886-3-5642050 t a i p e i b r a n c h : 2 f , n o . 1 1 , l a n e 2 1 8 , s e c 2 j h o n g s i n g r d . , s i n d i a n c i t y , t a i p e i c o u n t y 2 3 1 4 6 , t a i w a n t e l : 8 8 6 - 2 - 2 9 1 0 - 3 8 3 8 f a x : 8 8 6 - 2 - 2 9 1 7 - 3 8 3 8

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