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off - line pwm control lers with integrated power mosfet str - a6000 series str - a6000 - ds rev .4. 3 sanken electric co.,ltd. 1 m ar . 1 3 , 2 01 5 general descriptions the str - a6000 series are power ics for switching power supplies, incorporating a mosfet and a current mode pwm controller ic. the low standby power is accomplished by the automatic switching between the pwm operati on in normal operation and the burst - oscillation under light load conditions. the product achieves high cost - performance power supply systems with few external components. features ? current mode type pwm control ? brown - in and brown - out function ? auto standby function no load power consumption < 2 5mw ? operation mode normal operation ----------------------------- pwm mode standby ---------------------------- burst oscillation mode ? random switching function ? slope compe n sation function ? leading edge blanking function ? bias assist function ? audible noise suppression function during standby mode ? protections ? overcurrent protection (ocp) * ; pulse - by - pulse , built - in compensation circuit to minimize ocp point variation on ac input voltage ? overload protection (olp) ; a uto - r estart ? overvoltage protection (ovp) ; latched shutdown ? thermal shutdown protection (tsd) ; latched shutdown *str - a60 hd has two types ocp typical application circuit package dip8 not to scale lineup ? electrical characteristics products v d ss ( min .) f osc(avg) str - a605 m 650 v 67 khz str - a607 m 800 v str - a605 h 650 v 100 khz str - a606 h 700 v str - a606 hd 700 v 100 khz * str - a60 hd has two types ocp ? mosfet on resistance and output power , p out * products r ds(on) (max.) p out ( adapter ) p out (open frame) ac230v ac85 ~265v ac230v ac85 ~265v f osc(avg) = 67 khz str - a6051m 3.95 18.5 w 14 w 31 w 2 1 w str - a6052m 2.8 22 w 17.5 w 35 w 24.5 w str - a6053m 1.9 26 w 21 w 40 w 28 w str - a6079m 19.2 8 w 6 w 13 w 9 w f osc(avg) = 100 khz str - a6059h 6 17 w 11 w 30 w 19.5 w str - a6069h str - a6069hd str - a6061h 3.95 2 0 w 15 w 35 w 23.5 w str - a6061hd str - a6062h 2.8 23 w 18 w 38 w 26.5 w str - a6062hd str - a6063hd 2.3 25 w 20 w 40 w 28 w * the output power is actual continues power that is measured at 50 c ambient. t he peak output power can be 120 to 140 % of the value stated here. c ore size, on duty, and thermal design affect the output power . it may be less than the value stated here. applications ? low powe r ac/dc adapter ? white goods ? auxiliary power supply ? oa, av and industrial equipment http://www.sanken - ele.co.jp/en/ v a c c 1 c 6 r 1 d 1 b r 1 r 2 c 2 t 1 d p p c 1 c 3 r o c p c y c 5 1 2 3 4 d / s t d / s t b r n c s / o c p f b / o l p g n d v c c 8 7 5 s t r - a 6 0 0 0 u 1 d 2 c 4 r c r b r a d 5 1 c 5 1 r 5 1 r 5 2 u 5 1 r 5 4 r 5 6 c 5 2 s p c 1 r 5 3 r 5 5 l 5 1 c 5 3 v o u t ( + ) t c _ s t r - a 6 0 0 0 _ 1 _ r 1 ( - )
str - a6000 series str - a6000 - ds rev .4. 3 sanken electric co.,ltd. 2 m ar . 1 3 , 2 01 5 contents general descriptions -------------------------------- -------------------------------- ------- 1 1. absolute maximum ratings -------------------------------- ------------------------- 3 2. electrical characteristics -------------------------------- ---------------------------- 4 3. p erformance curves -------------------------------- -------------------------------- -- 6 3.1 derating curves -------------------------------- ------------------------------- 6 3.2 ambient temperature versus power dissipation curve ------------- 6 3.3 mosfet safe operating area curves -------------------------------- -- 7 3.4 transient thermal resistance curves -------------------------------- --- 9 4. functional block diagram -------------------------------- -------------------------- 11 5. pin configuration definitions -------------------------------- ---------------------- 11 6. typical application circuit -------------------------------- ------------------------ 12 7. package outline -------------------------------- -------------------------------- ------- 13 8. marking diagram -------------------------------- -------------------------------- ---- 13 9. operational description -------------------------------- ----------------------------- 14 9.1 startup operation -------------------------------- --------------------------- 14 9.2 undervoltage lockout (uvlo) -------------------------------- ----------- 15 9.3 bias assist function -------------------------------- ------------------------- 15 9.4 constant output voltage control -------------------------------- -------- 15 9.5 leading edge blanking function -------------------------------- -------- 16 9.6 random switching function -------------------------------- -------------- 16 9.7 automatic standby mode function -------------------------------- ------ 16 9.8 brown - in and brown - out function -------------------------------- ----- 17 9.9 overcurrent protection function (ocp) ------------------------------- 19 9.10 overload protection function (olp) -------------------------------- --- 20 9.11 overvoltage protection (ovp) -------------------------------- ------------ 20 9.12 thermal shutdown function (tsd) -------------------------------- ----- 2 0 10. design notes -------------------------------- -------------------------------- ----------- 21 10.1 external components -------------------------------- ----------------------- 21 10.2 pcb trace layout and component placement ----------------------- 22 11. pattern layout example -------------------------------- ---------------------------- 24 12. reference design of power supply -------------------------------- --------------- 25 operating precautions -------------------------------- ------------------------ 27 important notes -------------------------------- -------------------------------- --- 28
str - a6000 series str - a6000 - ds rev .4. 3 sanken electric co.,ltd. 3 m ar . 1 3 , 2 01 5 1. absolute maximum ratings ? the polarity value for current specifies a sink as "+," and a source as "?," referencing the ic. ? unless otherwise specified t a = 25 c , 7 pin = 8 pin parameter symbol test conditions pins rating units notes drain peak current ( 1 ) i dpeak single pulse 8 C a6079m 1.8 a6059h / 69h / 69hd 2.5 a6051m / 61h / 61hd 3.0 a6052m / 62h / 62hd 4.0 a6053m / 63hd avalanche energy ( 2 )( 3 ) e as i lpeak =1.2a 8 C a6079m i lpeak =1.8a 24 a6059h / 69h / 69hd i lpeak =2a 46 a6061h / 61hd i lpeak =2a 47 a6051m i lpeak =2.2a 56 a6062h / 62hd i lpeak =2.3a 62 a6052m i lpeak =2.5a 72 a6063hd i lpeak =2.7a 86 a6053m s/ocp pin voltage v s/o cp 1 ? ? br pin voltage v br 2 ? ? br pin sink current i br 2 ? fb/olp pin voltage v fb 4 ? ? fb/olp pin sink current i fb 4 ? vcc pin voltage v cc 5 ? mosfet power dissipation ( 4 ) p d1 ( 5 ) 8 C control part power dissipation p d2 5 C operating ambient temperature ( 6 ) t op ? ? stg ? ? ch ? 150 c ( 1 ) refer to 3.3 mosfet safe operating area curve s ( 2 ) refer to figure 3 - 2 avalanche energy derating coefficient curve ( 3 ) single pulse, v dd = 99 v, l = 20 mh ( 4 ) re fer to figure 3 - 3 ambient t emperature versus p ower d issipation c urve ( 5 ) when embedding this hybrid ic onto the printed circuit board (cupper area in a 15 mm 15 mm) ( 6 ) the recommended internal frame temperature, t f , is 115 c (max.)
str - a6000 series str - a6000 - ds rev .4. 3 sanken electric co.,ltd. 4 m ar . 1 3 , 2 01 5 2. electrical characteristics ? the polarity value for current specifies a sink as "+," and a source as "?," referencing the ic. ? unless otherwise specified, t a = 25 c , v cc = 18 v , 7 pin = 8 pin parameter symbol test conditions pins min. typ. max. units notes power supply startup operation operation start voltage v cc(on) 5 ? 3 ( 1 ) v cc(off) 5 ? 3 cc(on) v cc = 12 v 5 ? 3 ? ? st(on) 8 ? ? ? startup v cc = 13.5 v 5 ? 3 ? ? ? cc(bias) i cc = ? 100 a 5 ? 3 normal operation average switching frequency f osc(avg) 8 ? a 60 m 90 100 110 a 60 h / h d switching frequency modulation deviation ? ? ? a 60 m ? ? a 60 h / h d maximum on duty d max 8 ? minimum on time t on(min) 8 ? ? ? a 60 m ? ? a 60 h / h d protection function leading edge blanking time t bw ? ? ? a 60 m ? ? a 60 h / h d ocp compensation coefficient dpc ? ? ? mv/s a 60 m ? ? a 60 h / h d ocp compensation on duty d dpc ? ? ? ocp threshold voltage at zero on duty v ocp(l) 1 ? ocp threshold voltage at 36% on duty v ocp(h) v cc = 32 v 1 ? ocp threshold voltage in leading edge blanking time v ocp( leb ) 1 ? a 60 h d maximum feedback current i fb(max) v cc = 12 v 4 ? ? ? ? minimum feedback current i fb(min) 4 ? ? ? ? fb/olp pin oscillation stop threshold voltage v fb(stb) 4 ? olp threshold voltage v fb(olp) 4 ? olp operation current i cc(olp) v cc = 12 v 5 ? ? olp delay time t olp ? fb/olp pin clamp voltage v fb(clamp) 4 ? ( 1 ) v cc(bias) > v cc(off) always.
str - a6000 series str - a6000 - ds rev .4. 3 sanken electric co.,ltd. 5 m ar . 1 3 , 2 01 5 parameter symbol test conditions pins min. typ. max. units notes brown - in threshold voltage v br(in) v cc = 32 v 2 ? 3 5.2 5.6 6 v brown - out threshold voltage v br(out) v cc = 32 v 2 ? 3 4.45 4.8 5.15 v br pin clamp voltage v br(clamp) v cc = 32 v 2 ? 3 6 6.4 7 v br function disabling threshold v br(dis) v cc = 32 v 2 ? 3 0.3 0.48 0.7 v ovp threshold voltage v cc(ovp) 5 ? 3 26 29 3 2 v latch circuits holding current ( 2 ) i cc(latch) v cc = 9.5 v 5 ? 3 ? 700 ? a thermal shutdown operating temperature t j(tsd) ? 13 5 ? ? c mosfet drain - to - source breakdown voltage v dss 8 C 1 650 ? ? v a 605 700 ? ? a 606 8 00 ? ? a 607 drain leakage current i dss 8 C 1 ? ? 300 a on resistance r ds(on) i ds = 0.4a 8 ? 1 ? ? 19.2 a6079m ? ? 6 a6059h / 69h / 69hd ? ? 3.95 a6051m / 61h / 61hd ? ? 2.8 a6052m / 62h / 62hd ? ? 2.3 a6063hd ? ? 1.9 a6053m switching time t f 8 C 1 ? ? 250 ns ? ? 400 ns a6053m thermal resistance channel to case thermal resistance ( 3 ) ch - c ? ? ? 22 c/w ( 2 ) a latch circuit is a circuit operated with overvoltage protection function (ovp) and/or thermal shutdown function (tsd) in operation. ( 3 ) ch - c is thermal resist ance between channel and case. case temperature (t c ) is measured at the center of the case top surface.
str - a6000 series str - a6000 - ds rev .4. 3 sanken electric co.,ltd. 6 m ar . 1 3 , 2 01 5 3. performance curves 3.1 derating cu r ves figure 3 - 1 soa temperature derating coefficient curve figure 3 - 2 avalanche energy derating coefficient curve 3.2 ambient temperature versus power dissipation curve figure 3 - 3 ambient t emperature versus p ower d issipation c urve 0 20 40 60 80 100 0 25 50 75 100 125 150 safe operating area temperature derating coefficient (%) channel temperature, tch ( c) 0 20 40 60 80 100 25 50 75 100 125 150 e as temperature derating coefficient (%) channel temperature, tch ( c) 0 0.2 0.4 0.6 0.8 1 1.2 1.4 1.6 0 20 40 60 80 100 120 140 160 power dissipation, p d1 (w) ambient temperature, t a ( c ) 1.35w
str - a6000 series str - a6000 - ds rev .4. 3 sanken electric co.,ltd. 7 m ar . 1 3 , 2 01 5 3.3 mosfet safe operating area curve s ? when the ic is used, the safe operating area curve should be multiplied by the temperature derating c oefficient derived from figure 3 - 1 . ? the broken line in the safe operating area curve is the drain current curve limited by on - resistance. ? unless otherwise specified, t a = 25 c , single pulse ? str - a6051m ? str - a6052m ? str - a6053m ? str - a6079m 0.01 0.1 1 10 1 10 100 1000 drain current, i d (a) drain - to - source voltage (v) 0.01 0.1 1 10 1 10 100 1000 drain current, i d (a) drain - to - source voltage (v) 0.01 0.1 1 10 1 10 100 1000 drain current, i d (a) drain - to - source voltage (v) 0.01 0.1 1 10 1 10 100 1000 drain current, i d (a) drain - to - source voltage (v) 0.1ms 1ms 0.1ms 1ms 0.1ms 1ms 0.1ms 1ms
str - a6000 series str - a6000 - ds rev .4. 3 sanken electric co.,ltd. 8 m ar . 1 3 , 2 01 5 ? str - a6059h ? str - a6061h / 61hd ? str - a6062h / 62hd ? str - a 60 63hd ? str - a6069h / 69hd 0.01 0.1 1 10 1 10 100 1000 drain current, i d (a) drain - to - source voltage (v) 0.01 0.1 1 10 1 10 100 1000 drain current, i d (a) drain - to - source voltage (v) 0.01 0.1 1 10 1 10 100 1000 drain current, i d (a) drain - to - source voltage (v) 0.01 0.1 1 10 1 10 100 1000 drain current, i d (a) drain - to - source voltage (v) 0.1ms 1ms 0.1ms 1ms 0.1ms 1ms 0.1ms 1ms drain current, i d (a) drain - to - source voltage (v)
str - a6000 series str - a6000 - ds rev .4. 3 sanken electric co.,ltd. 9 m ar . 1 3 , 2 01 5 3.4 transient thermal resistance curve s ? str - a6051m / 61h / 61hd ? str - a6052m / 62h / 62hd ? str - a 60 5 3 m ? str - a 6059m / 69h / 69hd 0.01 0.1 1 10 transient thermal resistance ch - c ( c/w) time (s) 0.01 0.1 1 10 transient thermal resistance ch - c ( c/w) time (s) 0.01 0.1 1 10 transient thermal resistance ch - c ( c/w) time (s) 1 10 100 1m 10m 100m 1 10 100 1m 10m 100m 1 10 100 1m 10m 100m 1 10 100 1m 10m 100m time (s) 10 1 0.1 0.01 transient thermal resistance ch - c ( c /w) str-a6252 ^ transient thermal resistance curve 0.01 0.1 1 10 1.0e-06 1.0e-05 1.0e-04 1.0e-03 1.0e-02 1.0e-01 rg t [sec] time ^?? ch-c[ /w] transient thermal resistance
str - a6000 series str - a6000 - ds rev .4. 3 sanken electric co.,ltd. 10 m ar . 1 3 , 2 01 5 ? str - a 6079m ? str - a 6063hd 0.01 0.1 1 10 transient thermal resistance ch - c ( c/w) time (s) 100n 1 10 100 1m 10m 100m 1 10 100 1m 10m 100m time (s) 10 1 0.1 0.01 0.001 transient thermal resistance ch - c ( c /w) str-a6063hd ^ transient thermal resistance curve 0.001 0.01 0.1 1 10 1.0e-06 1.0e-05 1.0e-04 1.0e-03 1.0e-02 1.0e-01 rg t [sec] time ^?? ch-c[ /w] transient thermal resistance
str - a6000 series str - a6000 - ds rev .4. 3 sanken electric co.,ltd. 11 m ar . 1 3 , 2 01 5 4. functional block diagram 5. pin configuration definitions pin name descriptions 1 s/ocp mosfet source and overcurrent protection (ocp) signal input 2 br brown - in and brown - out detection voltage input 3 gnd ground 4 fb /olp c onstant voltage control signal input and over load protection (olp) signal input 5 vcc power supply voltage input for control part and overvoltage protection (ovp) signal input 6 ? u v l o o v p t s d r e g b r o w n - i n b r o w n - o u t p w m o s c o l p f e e d b a c k c o n t r o l s l o p e c o m p e n s a t i o n l e b d r a i n p e a k c u r r e n t c o m p e n s a t i o n o c p s t a r t u p d r v v r e g 6 . 4 v 1 2 . 8 v 7 v v c c v c c b r f b / o l p d / s t s / o c p g n d 7 , 8 1 3 4 2 5 s r q b d _ s t r - a 6 0 0 0 _ r 1 1 5 6 7 8 4 3 2 s / gnd br gnd fb / olp vcc d / st d / st
str - a6000 series str - a6000 - ds rev .4. 3 sanken electric co.,ltd. 12 m ar . 1 3 , 2 01 5 6. typical application circuit ? the following drawings show circuits enabled and disabled the brown - in/brown - out function. ? the pcb traces d/st pins should be as wide as possible, in order to enhance thermal dissipation. ? in applications having a power supply specified such that d/st pin has large transient surge voltages, a clamp snubber circuit of a capacitor - resistor - diode (c rd) combination should be added on the primary winding p, or a damper snubber circuit of a capacitor (c) or a resistor - capacitor (rc) combination should be added between the d/st pin and the s/ ocp pin. figure 6 - 1 typical application circuit (enabled brown - in/brown - out function , dc line detection) figure 6 - 2 typical application circuit (disabled brown - in/brown - out function ) v a c c 1 c 6 r 1 d 1 b r 1 r 2 c 2 t 1 d p p c 1 c 3 r o c p c y c r d c l a m p s n u b b e r c 5 c r c d a m p e r s n u b b e r 1 2 3 4 d / s t d / s t b r n c s / o c p f b / o l p g n d v c c 8 7 5 s t r - a 6 0 0 0 u 1 d 2 c 4 r c r b r a d 5 1 c 5 1 r 5 1 r 5 2 u 5 1 r 5 4 r 5 6 c 5 2 s p c 1 r 5 3 r 5 5 l 5 1 c 5 3 v o u t ( + ) t c _ s t r - a 6 0 0 0 _ 2 _ r 1 ( - ) v a c c 1 c 6 r 1 d 1 b r 1 r 2 c 2 t 1 d p p c 1 c 3 r o c p c y c r d c l a m p s n u b b e r c 5 c r c d a m p e r s n u b b e r 1 2 3 4 d / s t d / s t b r n c s / o c p f b / o l p g n d v c c 8 7 5 s t r - a 6 0 0 0 u 1 d 2 d 5 1 c 5 1 r 5 1 r 5 2 u 5 1 r 5 4 r 5 6 c 5 2 s p c 1 r 5 3 r 5 5 l 5 1 c 5 3 v o u t t c _ s t r - a 6 0 0 0 _ 3 _ r 1 ( + ) ( - )
str - a6000 series str - a6000 - ds rev .4. 3 sanken electric co.,ltd. 13 m ar . 1 3 , 2 01 5 7. package outline ? dip8 ? the following show a representative type of dip8. 8. marking diagram notes: 1) dimension is in millimeters 2) pb - free. device composition compliant with the rohs directive 1 8 part number a 6 0 s k y m d sanken c ontrol n umber str - a 60 m str - a 60 h lot number y is the l ast di git of the y ear ( 0 to 9 ) m is the month ( 1 to 9 , o , n or d ) d is a period of days : 1 : 1 st to 10 th 2 : 11 th to 20 th 3 : 21 st to 31 st 1 8 part number a 6 0 h s k y m d d sanken c ontrol n umber str - a 60 hd lot number y is the l ast di git of the y ear ( 0 to 9 ) m is the month ( 1 to 9 , o , n or d ) d is a period of days : 1 : 1 st to 10 th 2 : 11 th to 20 th 3 : 21 st to 31 st
str - a6000 series str - a6000 - ds rev .4. 3 sanken electric co.,ltd. 14 m ar . 1 3 , 2 01 5 9. operational description ? all of the parameter values used in these descriptions are typical values, unless they are specified as minimum or maximum. ? with regard to current direction, "+" indicates sink current (toward the ic) and " C " indicates source current (from the ic). 9.1 startup operation figure 9 - 1 shows the circuit around ic. figure 9 - 2 shows the start up operation . the ic incorpor ates the startup circuit. the circuit is connected to d/st pin. when d/st pin voltage reaches to startup circuit operation voltage v st(on) = 38 v , the startup circuit starts operation. during the startup process, the constant current, i startup = ? 2.5 ma , charges c2 at vcc pin. when vcc pin voltage increases to v cc(on) = 15.3 v , the control circuit starts operation. during the ic operation, the voltage rectifi ed the auxiliary winding voltage, v d , of figure 9 - 1 becomes a power source to the vcc pin. after switching operation begins, the startup circuit turns off automatically so that its current consumption becomes zero. the approximate value of au xiliary winding voltage is about 15 v to 20 v , taking account of the winding turns of d winding so that vcc pin voltage becomes equation ( 1 ) within th e specification of input and output voltage variation of power supply. ? ? without brown - in / brown - out function (br pin voltage is v br ( dis ) = 0.48 v or less ) when vcc pin voltage increases to v cc(on) , the ic starts switching operation , as shown in figure 9 - 2 . the startup time of ic is determined by c2 capacitor value. the approximate startup time t start (shown in figure 9 - 2 ) is calculated as follows: ( 2 ) where, t start : startup time of ic (s) v cc(int) : initial voltage on vcc pin (v) ? with brown - in / brown - out function when br pin voltage is more than v br ( dis ) = 0.48 v and less than v br ( i n) = 5.6 v , the bias assist function (refer to section 9.3 ) is disabled . t hus, vcc pin voltage repeats increasing to v cc(on) and decreasing to v cc(off) (shown in figure 9 - 3 ). when br pin voltage becomes v br ( i n) or more , the ic starts switching operation. figure 9 - 1 vcc pin peripheral circuit (without brown - in / brown - out) figure 9 - 2 startup operation (with out brown - in / brown - out) figure 9 - 3 startup operation (with brown - in / brown - out) .) (min v v .) (max v ) ovp ( cc cc ) bias ( cc ? ? ? ? cc v stratup ) int ( cc ) on ( cc start i v v c2 t ? v a c c 1 d 2 r 2 c 2 t 1 d p b r 1 v c c g n d d / s t 7 , 8 3 5 u 1 v d b r 2 v c c ( o n ) v c c p i n v o l t a g e d r a i n c u r r e n t , i d t s t a r t v c c ( o n ) v c c p i n v o l t a g e d r a i n c u r r e n t , i d t s t a r t b r p i n v o l t a g e v b r ( i n ) v c c ( o f f )
str - a6000 series str - a6000 - ds rev .4. 3 sanken electric co.,ltd. 15 m ar . 1 3 , 2 01 5 9.2 undervoltage lockout (uvlo) figure 9 - 4 shows the relationship of vcc pin voltage and circuit current i cc . when vcc pin voltage decreases to v cc(off) = 8.1 v , the control circuit stops operation by uvlo (undervoltage lockout) circuit, and reverts to the state before startup. figure 9 - 4 relationship between vcc pin voltage and i cc 9.3 bias assist function figure 9 - 5 shows vcc pin voltage behavior during the startup period. after vcc pin voltage increases to v cc(on) = 15.3 v at startup, the ic starts the operation. then circuit current increases and vcc pin voltage decreases. at the same time, the auxiliary winding voltage v d incre ases in proportion to output voltage. these are all balanced to produce vcc pin voltage. figure 9 - 5 vcc pin voltage dur i ng startup period the surge voltage is induced at output winding at turning off a power mosfet. when the output load is light at startup, the surge voltage causes the unexpected feedback control. this results the lowering of the output power and vcc pin voltage. when the vc c pin voltage decreases to v cc(off) = 8.1 v , the ic stops switching operation and a startup failure occurs. in order to prevent this, the bias assist function is ac tivated when the vcc pin voltage decreases to the startup current threshold biasing voltage, v cc(bias) = 9.5 v . while the bias assist function is activated, any decrease of the vcc pin voltage is counteracted by providing the startup current, i startup , from the startup circuit. thus, the vcc pin voltage i s kept almost constant. by the bias assist function, the value of c2 is allowed to be small and the startup time becomes shorter. also, because the increase of vcc pin voltage becomes faster when the output runs with excess voltage, the response time of th e ovp function becomes shorter. it is necessary to check and adjust the startup process based on actual operation in the application, so that poor starting conditions may be avoided. 9.4 constant output voltage control the ic achieves the constant voltage cont rol of the power supply output by using the current - mode control method, which enhances the response speed and provides the stable operation. the fb/olp pin voltage is internally added the slope compensation at the feedback control (refer to section 4 functional block diagram ), and the target voltage, v sc , is generated. the ic compares the voltage, v rocp , of a current detection resistor with the target voltage, v sc , by the internal fb comparator, and controls the peak value of v rocp so that it gets close to v sc , as shown in figure 9 - 6 and figure 9 - 7 . figure 9 - 6 fb/olp pin peripheral circuit figure 9 - 7 drain current, i d , and fb comparator operation in steady operation c i r c u i t c u r r e n t , i c c i c c o n v c c o f f v c c o n v c c p i n v o l t a g e s t a r t s t o p i c s t a r t s o p e r a t i o n v c c p i n v o l t a g e v c c ( o n ) v c c ( b i a s ) v c c ( o f f ) s t a r t u p f a i l u r e s t a r t u p s u c c e s s t a r g e t o p e r a t i n g v o l t a g e t i m e b i a s a s s i s t p e r i o d i n c r e a s e w i t h r i s i n g o f o u t p u t v o l t a g e p c 1 c 3 r o c p 1 3 4 s / o c p f b / o l p g n d u 1 i f b v r o c p v s c f b c o m p a r a t o r d r a i n c u r r e n t , i d + - v o l t a g e o n b o t h s i d e s o f r o c p v r o c p t a r g e t v o l t a g e i n c l u d i n g s l o p e c o m p e n s a t i o n
str - a6000 series str - a6000 - ds rev .4. 3 sanken electric co.,ltd. 16 m ar . 1 3 , 2 01 5 ? light load conditions when load conditions become lighter, the output voltage, v out , increases. thus, the feedback current from the error amplifier on the secondary - side also increases. the feedback current is sunk at the fb/olp pin, transferred through a photo - coupler, pc1, and the fb/olp pin voltage decreases. thus, v sc decreases, and th e peak value of v rocp is controlled to be low, and the peak drain current of i d decreases. this control prevents the output voltage from increasing. ? heavy load conditions when load conditions become greater, the ic performs the inverse operation to that d escribed above. thus, v sc increases and the peak drain current of i d increases. this control prevents the output voltage from decreasing. in the current mode control method, when the drain current waveform becomes trapezoidal in continuous operating mode, even if the peak current level set by the target voltage is constant, the on - time fluctuates based on the initial value of the drain current. this results in the on - time fluctuating in multiples of the fundamental operating frequency as shown in figure 9 - 8 . this is called the subharmonics phenomenon. in order to avoid this, the ic incorporates the slope com pensation function. because the target voltage is added a down - slope compensation signal, which reduces the peak drain current as the on - duty gets wider relative to the fb/olp pin signal to compensate v sc , the subharmonics phenomenon is suppressed. even if subharmonic oscillations occur when the ic ha s some excess supply being out of feedback control, such as during startup and load shorted, this does not affect performance of normal operation. figure 9 - 8 drain current, i d , waveform in subharmonic oscillation 9.5 leading edge blanking function the ic uses the peak - current - mode control method for the constant voltage control of output. in peak - current - mode control method, there is a case that the power mosfet turns off due t o unexpected response of fb comparator or overcurrent protection circuit (ocp) to the steep surge current in turning on a power mosfet. in order to prevent this response to the surge voltage in turning - on the power mosfet, the leading edge blanking, t bw ( s tr - a60 h for 3 4 0 ns , str - a60 h and str - a60 h d for 280 ns ) is built - in. during t bw , the ocp threshold voltage becomes about 1. 7 v which is higher than the normal ocp threshold voltage ( refer to section 9.9 ). 9.6 random switching function the ic modulates its switching frequency randomly by supe rposing the modulating frequency on f osc(avg) in normal operation. this function reduces the conduction noise compared to others without this function, and simplifies noise filtering of the input lines of power supply. 9.7 automatic standby mode function autom atic standby mode is activated automatically when the drain current, i d , reduces under light load conditions, at which i d is less than 15 % to 2 0 % of the maximum drain current (it is in the ocp state). the operation mode becomes burst oscillation, as shown in figure 9 - 9 . burst oscillation mode reduces switching losses and improves power suppl y efficiency because of periodic non - switching intervals. figure 9 - 9 auto standby mode timing generally, to improve efficiency under light load conditions, the frequency of the burst oscillation mode becomes just a few kilohertz. because the ic suppresses the peak drain current well during burst oscillation mode, audible noises can be reduced. if the vcc pin voltage decreases to v cc(bias) = 9.5 v t o n 1 t a r g e t v o l t a g e w i t h o u t s l o p e c o m p e n s a t i o n t o n 2 t t t normal operation standby operation normal operation burst oscillation output current , i out drain current , i d below several khz
str - a6000 series str - a6000 - ds rev .4. 3 sanken electric co.,ltd. 17 m ar . 1 3 , 2 01 5 during the transition to the burst oscillation mode, the bias assist function is activated and stabilizes the standby mode operation, because i startup is provided to the vcc pin so that the vcc p in voltage does not decrease to v cc(off) . however, if the bias assist function is always activated during steady - state operation including standby mode, the power loss increases. therefore, the vcc pin voltage should be more than v cc(bias) , for example, by adjusting the turns ratio of the auxiliary winding and secondary winding and/or reducing the value of r2 in figure 10 - 2 (refer to sec tion 10.1 peripheral components for a detail of r2). 9.8 brown - in and brown - out function this function stops switching operation when it detects low in put line voltage, and thus prevents excessive input current and overheating. this function turns on and off switching operation according to the br pin voltage detecting the ac input voltage . when br pin voltage becomes more than v br(dis) = 0.48 v, this function is activated. figure 9 - 10 shows waveforms of the br pin voltage and the drain currnet. even if the ic is in the operating state that the vcc pin voltage is v cc(off) or more, when the ac input voltage decreases from steady - state and the br pin voltage falls to v br(out) = 4.8 v or less for the olp delay time, t olp = 68 ms, the ic stops switching operation. when the ac input voltage increases and the br pin voltage reaches v br(in) = 5.6 v or more in the operating state that the vcc pin voltage is v cc(off) or more, the ic starts switching operation. in case the brown - in and brown - out function is u nnecessary, connect the br pin trace to the gnd pin trace so that the br pin voltage is v br(dis) or less. figure 9 - 10 br pin voltage and drain current waveforms during burst oscillation mode , this function operates as follows: ? str - a60 m and str - a60 h : t his function is disabled during switching operation stop period in burst oscillation mode. when the br pin voltage falls to v br(out) or less in burst oscillation mode and the sum of switching operation period becomes t olp = 68 ms or more, the ic stops switching operation . ? str - a6 0hd : when the br pin voltage falls to v br(out) = 4.8 v or less for t olp = 68 ms, the ic stops switching operation. there are two types of detection method as follows: 9.8.1 dc line detection figure 9 - 11 shows br pin peripheral circuit of dc line detection. there is a ripple voltage on c1 occurring at a half period of ac cycle. in order to detect each peak of the ripple voltage, t he time constant of r c and c4 should be shorter than a half period of ac cycle. since the cycle of the ripple voltage is shorter than t olp , the switching operation does not stop when only the bottom part of the ripple voltage becomes lower than v br(out) . thus it minimizes the influen ce of load conditions on the voltage detection. figure 9 - 11 dc line detection the components around br pin: ? r a and r b are a few megohms. because of high voltage applied and high resistance, it is recommended to select a resistor designed against electromigration or use a combination of resistors in series for that to reduce each applied voltage, according to the requirement of the application. ? r c is a few hundred kilohms ? c4 is 470 pf to 2200 pf for high frequency noise reduction neglecting the effect of both input resistance and forward voltage of rectifier diode, the reference value of c1 voltage when brown - in and brown - out function is activated is calculated as follows: b r p i n v o l t a g e v b r ( i n ) v b r ( o u t ) t o l p d r a i n c u r r e n t , i d v d c u 1 b r 2 c 4 r c g n d 3 r b r a v a c b r 1 c 1
str - a6000 series str - a6000 - ds rev .4. 3 sanken electric co.,ltd. 18 m ar . 1 3 , 2 01 5 ( 3 ) where, v dc(op) : c1 voltage when brown - in and brown - out function is activated v br(th) : any one of threshold voltage of br pin (see table 9 - 1 ) table 9 - 1 br pin threshold voltage parameter symbol value (typ.) brown - in threshold voltage v br(in) 5.6 v brown - out threshold voltage v br(out) 4.8 v v dc(op) can be expressed as the effective value of ac inpu t voltage using equation ( 4 ) . ( 4 ) r a , r b , r c and c4 should be selected based on actual operation in the application. 9.8.2 ac line detection figure 9 - 12 shows br pin peripheral circuit of ac line detection. in order to detect the ac input voltage, t he time constant of r c and c4 should be long er than the period of ac cycle. thus the response o f br pin detection becomes slow compared with the dc line detection. this method detects the ac input voltage, and thus it minimizes the influence from load conditions . also, this method is free of influence from c1 charging and discharging time, the latch mode can be released quickly* figure 9 - 12 ac line detection * high - speed latch release w hen overvoltage protection function (ovp) or thermal shutdown function (tsd) are activated , t he ic stops switching operation in latch mode. releasing the latch mode is done by decreasing the vcc pin voltage below v cc(off) or by decreasing the br pin voltage below v br(out) . in case of the dc line detection or without brown - in / brown - out function , the release time depends on discharge time of c1 and takes longer time until vcc pin voltage decreases to release voltage. in case of the ac line detection, br pin voltage is decreased quickly when ac input voltage, v ac , is turned off, and thus the latch mode is quickly released. the components around br pin: ? r a and r b are a few megohms. because of high voltage applied and high resistance, it is recommended to select a resistor designed against electromigration or use a combination of resistors i n series for that to reduce each applied voltage, according to the requirement of the application. ? r c is a few hundred kilohms ? r s must b e adjusted so that the br pin voltage is more than v br(dis) = 0.48 v when the vcc pin voltage is v cc(off) = 8.1 v ? c4 is 0.22 f to 1 f for averaging ac input voltage and h igh frequency noise reduction. neglecting the effect of input resistance is zero, the reference effective value of ac input voltage when brown - in and brown - out function is activated is calculated as follows: ( 5 ) where, v ac(op)rms : t he effective value of ac input voltage when brown - in and brown - out function is activated v br(th) :any one of threshold voltage of br pin (see table 9 - 1 ) r a , r b , r c and c4 should be selected based on actual operation in the application. ? ? ? ? ? ? ? ? ? ? ? ? c b a ) th ( br ) op ( dc r r r 1 v v ) op ( dc rms ) op ( ac v 2 1 v ? ? v d c u 1 b r 2 c 4 r c g n d 3 r b r a v a c b r 1 c 1 v c c 3 r s ? ? ? ? ? ? ? ? ? ? ? ? ? ? c b a ) th ( br rms ) op ( ac r r r 1 v 2 v
str - a6000 series str - a6000 - ds rev .4. 3 sanken electric co.,ltd. 19 m ar . 1 3 , 2 01 5 9.9 overcurrent pro tection function (ocp) overcurrent protection function (ocp) detects each drain peak current level of a power mosfet on pulse - by - pulse basis, and limits the output power when the current level reaches to ocp t hreshold v oltage . during leading edge blanking time, the opera tion of ocp is different depending on the products as follows. ? str - a60 h d : d uring leading edge blanking time, the ocp threshold voltage becomes v ocp(leb) = 1.55 v which is higher than the normal ocp threshold voltage as shown in figure 9 - 13 . changing to this threshold voltage prevent s the ic from responding to the surge voltage in turning - on the power mosfet . this function operates as protection at the condition such as output windings sho rted or unusual withstand voltage of secondary - side rectifier diodes. ? str - a60 m and str - a60 h: ocp is disabled during leading edge blanking time. when power mosfet turns on, the surge voltage width of s/ocp pin should be less than t bw , as shown in figure 9 - 13 . in order to prevent surge voltage, pay extra attention to r ocp t race l ayout (refer to section ). in addition, if a c (rc) damper snubber of figure 9 - 14 is used, reduce the ca pacitor value of damper snubber. figure 9 - 13 s/ocp pin voltage figure 9 - 14 damper snubber < input compensation f unction > ics with pwm control usually have some propagation delay time. the steeper the slope of the actual drain current at a high ac input voltage is, the larger the detection voltage of actual drain peak current is, compared to v oc p . thus, the peak current has some variation depending on the ac input voltage in ocp state. in order to reduce the variation of peak current in ocp state, the ic incorporates a built - in input compensation function. the input compensation f unction is the f unction of correction of ocp threshold voltage depending with ac input voltage, as shown in figure 9 - 15 . when ac input voltage is low (on duty is broad), the ocp threshold voltage is controlled to become high . the difference of peak drain current become small compared with the case where the ac input voltage is high (on duty is narrow). the compensation signal depends on on duty. the relation between the on duty and the ocp threshold voltage after compensation v ocp ' is expressed as equation ( 6 ) . when on duty is broader than 36 %, the v ocp ' becomes a constant value v ocp(h) = 0. 9 v figure 9 - 15 relationship between on duty and drain current limit after compensation ( 6 ) where, v ocp(l) : ocp threshold voltage at zero on duty dpc : ocp compensation coefficient ontime : on - time of power mosfet onduty : on duty of power mosfet f osc(avg) : average pwm switching frequency s u r g e p u l s e v o l t a g e w i d t h a t t u r n i n g o n t b w v o c p v o c p ( l e b ) ( s t r - a 6 0 h d ) c 1 t 1 d 5 1 r o c p u 1 c 5 1 c r c d a m p e r s n u b b e r 7 , 8 d / s t s / o c p 1 c r c d a m p e r s n u b b e r o n d u t y ( % ) d d p c v o c p ( l ) 0 d m a x 1 0 0 v o c p ( h ) 0 . 5 1 . 0 5 0 o c p t h r e s h o l d v o l t a g e a f t e r c o m p e n s a t i o n , v o c p ' ontime dpc v ' v ) l ( ocp ocp ? ? ? ) avg ( osc ) l ( ocp f onduty dpc v ? ? ?
str - a6000 series str - a6000 - ds rev .4. 3 sanken electric co.,ltd. 20 m ar . 1 3 , 2 01 5 9.10 overload protection function (olp) figure 9 - 16 shows the fb/olp pin peripheral circuit, and figure 9 - 17 shows each waveform for olp operation . when the peak drain current of i d is limited by ocp operation, the output voltage, v out , decreases and the feedback current from the secondary photo - coupler becomes zero. thus, the feedback current, i fb , charges c3 connected to the fb/olp pin and the fb/olp pin voltage increases. when the fb/olp pin voltage increases to v fb(olp) = 8.1 v or more for the olp delay time, t olp = 68 ms or more , the olp function is activated , the ic stops switching operation. during olp operation , bias assist function is disabled . t hus, vcc pin voltage decreases to v cc(off) , the control circuit stops operation. after that, the ic reverts to the initial state by uvlo circuit, and the ic starts operation when vcc pin voltage increases to v cc(on) by s tartup c urrent. thus the intermittent operation by uvlo is repeated in olp state . this intermittent operation reduces the stress of parts such as power mosfet and secondary side rectifier diode. in addition, this operation reduces power consumption because the switching period in this intermittent operation is short compared with oscillation stop period. when the abnormal condition is removed, the ic returns to normal operation automatically. figure 9 - 16 fb/olp pin peripheral circuit figure 9 - 17 olp operational waveforms 9.11 overvoltage protection (ovp) when a voltage between vcc pin and gnd pin increases to v cc(ovp) = 29 v or more, ovp f unction is activated , the ic stops switching operation at the latched state. in order to keep the latched state, when vcc pin voltage de creases to v cc(bias) , the bias assist function is activated and vcc pin voltage is kept to over the v cc(off) . releasing the latched state is done by turning off the input voltage and by dropping the vcc pin voltage below v cc(off) , or by dropping the br pin voltage below v br ( out ) . in case the vcc pin voltage is provided by using auxiliary winding of transformer, the overvoltage conditions such as output voltage detection circuit open can be detected because the vcc pin voltage is proportional to output v oltage. the approximate value of output voltage v out(ovp) in ovp condition is calculated by using equation ( 7 ) . 29 ( v ) ( 7 ) where, v out(normal) : output voltage in normal operation v cc(normal) : vcc pin voltage in normal operation 9.12 thermal shutdown function (tsd) when the temperature of control circuit increases to t j(tsd) = 13 5 c (min.) or more, thermal shutdown function (tsd) is activated , the ic stops switching operation at the latched state. in order to keep the latched state, when vcc pin voltage decreases to v cc(b ias) , the bias assist function is activated and vcc pin voltage is kept to over the v cc(off) . releasing the latched state is done by turning off the input voltage and by dropping the vcc pin voltage below v cc(off) , or by dropping the br pin voltage below v br ( out ) . p c 1 c 3 4 f b / o l p u 1 v c c 5 g n d 3 d 2 r 2 c 2 d v c c p i n v o l t a g e f b / o l p p i n v o l t a g e d r a i n c u r r e n t , i d v c c ( o f f ) v f b ( o l p ) t o l p v c c ( o n ) n o n - s w i t c h i n g i n t e r v a l t o l p ? ? ) normal ( cc ) normal ( out out(ovp) v v v
str - a6000 series str - a6000 - ds rev .4. 3 sanken electric co.,ltd. 21 m ar . 1 3 , 2 01 5 10. design notes 10.1 external components take care to use properly rated, including derating as necessary and proper type of components. figure 10 - 1 the ic peripheral circuit ? input and output electrolytic capacitor apply proper derating to ripple current, voltage, and temperature rise. use of high ripple current and low impedance types, designed for switch mode power supplies, is recommended. ? s/ocp pin peripheral circuit i n figure 10 - 1 , r ocp is the resistor for the current detection. a high frequency switching current flows to r ocp , and may cause poor operation if a high inductance resistor is used. choose a low inductance and high surge - tolerant type. ? br pin peripheral circuit because r a and r b (see figure 10 - 1 ) are applied high voltage and are high resistance, the following should be considered according to the requirement of the application: ? select a resistor designed against electromigration, or ? use a combination of resistors in series for that to reduce each appli ed voltage see the section 9.8 about the ac input voltage detection function and the components around br pin. when the detection resistor ( r a , r b , r c ) value is decreased and the c4 value is increased to prevent unstable operation resulting from noise at the br pin, pay attention to the low efficiency and the slow response of br pin . ? fb/olp pin peripheral circuit c3 is for high frequency noise reduction and phase compensation, and should be connected close to these pins. the value of c3 is recommended to be about 2200 p f to 0.01f, and should be selected based on actual operation in the application. ? vcc pin peripheral circuit the value of c2 in figure 10 - 1 is generally recommended to be 10 to 47f (refer to section 9.1 startup operation , because the startup time is determined by the value of c2) . in actual power supply circuits, there are cases in which the vcc pin voltage fluctuates in proportion to the output current, i out (see figure 10 - 2 ), and the overvoltage protection function (ovp) on the vcc pin may be activated. this happens because c2 is charged to a peak voltage on the auxiliary winding d, which is caused by the transient surge voltage coupled from the primary winding when the power mosfet turns off. for alleviating c2 peak charging, it is effective to add some value r2, of several tenths of ohms to several ohms, in seri es with d2 (see figure 10 - 1 ). the optimal value of r2 should be determined using a transformer matching what will be used in the actua l application, be cause the vari ation of the auxiliary winding voltage is affected by the transformer structural design. figure 10 - 2 variation of vcc pin voltage and power ? snubber circuit in case the s u rge voltage of v ds is large, the circuit should be added as follow s (see figure 10 - 1 ) ; ? a clamp snubber circuit of a capacitor - resistor - diode (c rd) combination should be added on the primary winding p. ? a damper snubber circuit of a capacitor (c) or a resistor - capacitor (rc) combination should be added between the d/st pin and the s/ ocp pin. in case the damper snubber circuit is added, this compone nts should be connected near d/st pin and s/ocp pin. v a c c 1 c 6 r 1 d 1 b r 1 r 2 c 2 t 1 d p p c 1 c 3 r o c p c r d c l a m p s n u b b e r c 5 1 2 3 4 d / s t d / s t b r n c s / o c p f b / o l p g n d v c c 8 7 5 u 1 d 2 c 4 r c r b r a c ( r c ) d a m p e r s n u b b e r w i t h o u t r 2 w i t h r 2 v c c p i n v o l t a g e o u t p u t c u r r e n t , i o u t
str - a6000 series str - a6000 - ds rev .4. 3 sanken electric co.,ltd. 22 m ar . 1 3 , 2 01 5 ? peripheral circuit of secondary side shunt regulator figure 10 - 3 shows the secondary side detection circuit with the standard shunt re gulator ic (u51) . c52 and r53 are for phase compensation. the value of c52 and r53 are recommended to be around 0.047f to 0.47f and 4.7 k to 470 k , respectively. they should be selected based on actual operation in the application. figure 10 - 3 peripheral circuit of secondary side shunt regulator (u51) ? transformer apply proper design margin to core temperature rise by core loss and copper loss. because the switching currents contain high frequency currents, the skin effect may become a consideration. choose a suitable wire gauge in consideration of the rms current and a current density of 4 to 6 a/mm 2 . if measures to further reduce temperature are still necessary, the following should be considered to increase the total surface area of the wiring: ? incr ease the number of wires in parallel. ? use litz wires. ? thicken the wire gauge. in the following cases, t he surge of vcc pin voltage becomes high. ? the surge voltage of primary main winding , p, is high ( low output voltage and high output current power supply designs ) ? the winding structur e of auxiliary winding , d , is susceptible to the noise of winding p. when t he surge voltage of winding d is high, the vcc pin voltage increases and the overvoltage protection function (ovp) may be activated . in transformer design, the following should be considered; ? t he coupling of the winding p and the secondary output winding s should be maximize d to reduce the leakage inductance. ? t he coupling of the winding d and the winding s should be maximize d. ? t he coupling of the wind ing d and the winding p should be minimize d. in the case of multi - output power supply, t he coupling of the secondary - side stabilized output winding, s1, and the others (s2, s3 ) should be maximize d to improve the line - regulation of those outputs . figure 10 - 4 shows the winding structural examples of two outputs. winding structural example (a): s1 is sandwiched between p1 and p2 to maximize the cou pling of them for surge reduction of p1 and p2. d is placed far from p1 and p2 to minimize the coupling to the primary for the surge reduction of d. winding structural example (b) p1 and p2 are placed close to s1 to maximize the coupling of s1 for surge reduction of p1 and p2. d and s2 are sandwiched by s1 to maximize the coupling of d and s1, and that of s1 and s2. this structure reduces the surge of d, and improves the line - regulation of outputs. figure 10 - 4 winding structural examples 10.2 pcb trace layout and component placement since the pcb circuit trace design and the component layout significantly affects operation, emi noise, and power dissipation , the high frequency pcb trace should be low impedance with small loop and wide trace. in addition, the ground traces affect radiated emi noise, and wide, short traces should be taken into account. d 5 1 c 5 1 r 5 1 r 5 2 u 5 1 r 5 4 r 5 6 c 5 2 s p c 1 r 5 3 r 5 5 l 5 1 c 5 3 v o u t ( - ) t 1 ( + ) m a r g i n t a p e m a r g i n t a p e m a r g i n t a p e m a r g i n t a p e p 1 s 1 p 2 s 2 d p 1 s 1 d s 2 s 1 p 2 w i n d i n g s t r u c t u r a l e x a m p l e ( a ) w i n d i n g s t r u c t u r a l e x a m p l e ( b ) b o b b i n b o b b i n
str - a6000 series str - a6000 - ds rev .4. 3 sanken electric co.,ltd. 23 m ar . 1 3 , 2 01 5 figure 10 - 5 shows the circuit design example. (1) main circuit trace layout this is the main trace containing switching currents, and thus it should be as wide trace and small loop as possible. if c 1 and the ic are distant from each other, placing a capacitor such as film capacitor (about 0.1 f and with proper voltage rating) close to the transformer or the ic is recommended to reduce impedance of the high frequency current loop. (2) control ground trace layout since the operation of ic may be affected from the large current of the main trace that flows in control ground trace, the control ground trace should be separate d from main trace and connected at a single point grounding of point a in figure 10 - 5 as close to the r ocp pin as possible. (3) vcc trace layout this is the trace for supplying power to the ic, and thus it should be as small loop as possible. if c 2 and the ic are distant from each other, placing a capacitor such as film capacitor c f ( about 0.1 f to 1.0 f) close to the vcc pin and the gnd pin is recommended. (4) r ocp trace layout r ocp should be placed as close as possible to the s/ ocp pin. the connect ion between the power ground of the main trace and the ic ground should be at a single point ground (point a in figure 10 - 5 ) which is close to the base of r ocp . (5) peripheral components of the ic the components for control connected to the ic should be placed as close as possible to the ic, and should be connected as short as possible to the each pin. (6) secondary rectifier smoothing circuit trace layout : th is is the trace of the rectifier smoothing loop, carr ying the switching current , and thus it should be as wide trace and small loop as possible. if this trace is thin and long, inductance resulting from the loop may increase surge voltage at turning off th e power mosfet. proper rectifier smoothing trace layout helps to increase margin against the power mosfet breakdown voltage, and reduces s tress on the clamp snubber circuit and losses in it. (7) thermal c onsideration s because the power mosfet has a positive th ermal coefficient of r ds(on) , consider it in thermal design. since the copper area under the ic and the d/st pin trace act as a heatsink, its traces should be as wide as possible. figure 10 - 5 peripheral circuit example around the ic c 1 c 6 r 1 d 1 d 2 r 2 c 2 t 1 c 5 1 d p s p c 1 c 3 r o c p c 5 1 2 3 4 d / s t b r n c s / o c p f b / o l p g n d 8 7 5 s t r - a 6 0 0 0 u 1 a d s t c y d 5 1 d / s t v c c r c r a r b c 4 ( 1 ) m a i n t r a c e s h o u l d b e w i d e t r a c e a n d s m a l l l o o p ( 6 ) m a i n t r a c e o f s e c o n d a r y s i d e s h o u l d b e w i d e t r a c e a n d s m a l l l o o p ( 2 ) c o n t r o l g n d t r a c e s h o u l d b e c o n n e c t e d a t a s i n g l e p o i n t a s c l o s e t o t h e r o c p a s p o s s i b l e ( 3 ) l o o p o f t h e p o w e r s u p p l y s h o u l d b e s m a l l ( 4 ) r o c p s h o u l d b e a s c l o s e t o s / o c p p i n a s p o s s i b l e . ( 7 ) t r a c e o f d / s t p i n s h o u l d b e w i d e f o r h e a t r e l e a s e ( 5 ) t h e c o m p o n e n t s c o n n e c t e d t o t h e i c s h o u l d b e a s c l o s e t o t h e i c a s p o s s i b l e , a n d s h o u l d b e c o n n e c t e d a s s h o r t a s p o s s i b l e
str - a6000 series str - a6000 - ds rev .4. 3 sanken electric co.,ltd. 24 m ar . 1 3 , 2 01 5 11. pattern layout example the following show the pcb pattern layout example and the schematic of circuit using str - a6000 series. the above circuit symbols correspond to these of figure 11 - 1 . only the parts in the schematic are used. other parts in pcb are leaved open. figure 11 - 1 pcb circuit trace layout example figure 11 - 2 circuit schematic for pcb circuit trace layout 3 c n 1 c 3 t 1 d 5 1 r 5 2 u 5 1 d 1 p 1 s 1 p c 1 4 l 5 1 l 2 c 5 2 r 5 3 c 4 f 1 1 3 c 1 t h 1 l 1 n c 1 2 4 d / s t d / s t b r s / o c p f b / o l p v c c 8 7 5 s t r - a 6 0 0 0 u 1 g n d 3 1 2 o u t 2 ( + ) c 5 c 7 c 6 c 8 c 1 0 c 1 1 d 2 d 3 d 4 d 1 d 7 d 8 r 3 r 4 r 1 r 5 r 7 r 6 d 5 2 c 5 1 c 5 3 c 5 5 r 5 1 r 5 4 r 5 5 r 5 6 r 5 7 r 5 8 r 5 9 r 6 0 r 6 1 j w 5 1 j w 5 2 j w 2 j w 3 c p 1 c 5 4 c 5 7 c n 5 1 c 2 c 9 j w 4 o u t 2 ( - ) o u t 1 ( + ) o u t 1 ( - ) 1 2 o u t 3 ( + ) d 2 1 c 2 1 r 2 1 o u t 3 ( - ) i n o u t g n d 1 2 3 u 2 1 c 2 2 d 2 1 2 o u t 4 ( + ) d 3 1 c 3 1 r 3 1 o u t 4 ( - ) c 3 2 j w 3 1 j w 2 1 c n 2 1 c n 3 1 r 2 l 5 2 c 5 6 c 1 2 c 1 3 j w 6 j w 7 j w 8 j w 9 j w 1 0 j w 1 1 j w 5 3 j w 5 4
str - a6000 series str - a6000 - ds rev .4. 3 sanken electric co.,ltd. 25 m ar . 1 3 , 2 01 5 12. reference design of power supply as an example, the following show the power supply specification, the circuit schematic, the bill of materials, and the transformer specification. ? power supply specification ic str - a6059h input voltage a c85v to ac265v maximum output power 7.5w output voltage 5v output cirrent 1.5a (max.) ? circuit schematic ? bill of materials symbol part type ratings (1) recommended sanken parts symbol part type ratings (1) recommended sanken parts f1 fuse ac250v , 3 a r4 (3) metal oxide 330k , 1w l1 (2) cm i nductor 3.3mh r7 general 330k l2 (2) inductor 470 h r8 (3) general 2.2m th1 (2) ntc thermistor short r9 (3) general 2.2m d1 general 600v , 1a em01a pc1 photo - coupler pc123 or equiv d2 general 600v , 1a em01a u1 ic str - a6059h d3 general 600v , 1a em01a t1 transformer see the specification d4 general 600v , 1a em01a l51 inductor 5 h d5 fast re covery 1000v, 0.5a eg01c d51 schottky 90v, 4a fmb - g19l d6 fast re covery 200v , 1a al01z c51 electrolytic 680 f , 10 v c1 (2) film, x2 0.047 f, 275v c52 (2) ceramic 0.1 f , 50v c2 electro lytic 1 0f , 4 0 0v c53 electrolytic 330 f , 10v c3 electrolytic 1 0f , 4 0 0v c55 (2) ceramic 10 00pf , 1k v c4 ceramic 1000p f , 630 v r51 general 220 c5 electro lytic 22 f , 5 0v r52 general 1.5k c6 (2) cera mic 0.01 f r53 (2) general 22k c7 (2) cera mic 1000pf r54 general, 1% short c8 (2) ceramic open r55 general, 1% 10k c9 ceramic , y1 2200pf, 250v r56 general, 1% 10k r1 (2) gen eral open r57 general open r2 (2) general 4.7 u51 shunt regulator v ref =2.5v tl431 or equiv r3 general 1.5 , 1/2w (1) unless othe rwise specified, the voltage rating of capacitor is 50 v or less and the power rating of resistor is 1/8 w or less. (2) it is necessary to be adjusted based on actual operation in the application. (3) resistors applied high dc voltage and of high resistance are re commended to select resistors designed against electromigration or use combinations of resistors in series for that to reduce each applied voltage, according to the requirement of the application. 3 c 3 t 1 d 5 1 r 5 2 u 5 1 d p 1 s 2 p c 1 4 l 5 1 l 2 c 5 2 r 5 3 c 2 f 1 1 3 c 1 t h 1 l 1 r 1 n c 1 2 4 d / s t d / s t b r s / o c p f b / o l p v c c 8 7 5 s t r - a 6 0 0 0 u 1 g n d 3 5 v / 1 . 5 a c 4 c 6 c 7 c 5 c 8 c 9 d 2 d 5 d 6 r 2 r 3 r 4 r 7 r 8 r 9 c 5 1 c 5 3 r 5 1 r 5 4 r 5 5 r 5 6 r 5 7 p c 1 c 5 5 s 1 d 1 d 3 d 4 t c _ s t r - a 6 0 0 0 _ 4 _ r 1 v o u t ( + ) v o u t ( - )
str - a6000 series str - a6000 - ds rev .4. 3 sanken electric co.,ltd. 26 m ar . 1 3 , 2 01 5 ? transformer specification ? primary inductance, l p 704 h ? c ore size ei - 16 ? al - value 132 nh/n 2 (center gap of about 0. 26 mm ) ? winding specification winding symbol number of turns (t) wire diameter (mm) construction primary winding p1 73 2uew - 0.18 0.182 0.32 0.32 b o b b i n d s 1 p 1 v d c d / s t v c c g n d v o u t ( + ) 5 v s 2 s 1 d p 1 s 2 : s t a r t a t t h i s p i n c r o s s - s e c t i o n v i e w v o u t ( - )
str - a6000 series str - a6000 - ds rev .4. 3 sanken electric co.,ltd. 27 m ar . 1 3 , 2 01 5 operating precautions in the case that you use sanken products or design your products by using sanken products, the reliability largely depends on the degree of derating to be made to the rated values. derating may be interpreted as a case that an operation range is set by derating t he load from each rated value or surge voltage or noise is considered for derating in order to assure or improve the reliability. in general, derating factors include electric stresses such as electric voltage, electric current, electric power etc., enviro nmental stresses such as ambient temperature, humidity etc. and thermal stress caused due to self - heating of semiconductor products. for these stresses, instantaneous values, maximum values and minimum values must be taken into consideration. in addition, it should be noted that since power devices or ics including power devices have large self - heating value, the degree of derating of junction temperature affects the reliability significantly. because reliability can be affected adversely by improper stor age environments and handling methods, please observe the following cautions. cautions for storage ? ensure that storage conditions comply with the standard temperature (5 to 35c) and the standard relative humidity (around 40 to 75%) ; avoid storage location s that experience extreme changes in temperature or humidity. ? avoid locations where dust or harmful gases are present and avoid direct sunlight. ? reinspect for rust on leads and solderability of the products that have been stored for a long time. cautions for testing and handling when tests are carried out during inspection testing and other standard test periods, protect the products from power surges from the testing device, shorts between the product pins, and wrong connections. ensure all test parameter s are within the ratings specified by sanken for the product s . remarks about using thermal silicone grease ? when thermal silicone grease is used, it shall be applied evenly and thinly. if more silicone grease than required is applied, it may produce excess stress. ? the thermal silicone grease that ha s been stored for a long period of time may cause cracks of the greases , and it cause low radiation performance. in addition, the old grease may cause cracks in the resin mold when screwing the products to a heats ink. ? fully consider preventing foreign mat erials from entering into the thermal silicone grease. when foreign mat erial is immixed, radiation performance may be degraded or an insulation failure may occur due to a damaged insulating plate. ? the thermal silic on e greases that are recommended for the resin molded semiconductor should be used. our recommended thermal silicone grease is the following, and equivalent of these. type suppliers g746 shin - etsu chemical co., ltd. yg6260 momentive performance materials japan llc sc102 dow corning toray co., ltd. soldering ? when soldering the products, please be sure to minimize the working time, within the following limits: ? 260 5 c 10 1 s (flow, 2 times) ? 380 10 c 3 .5 0.5 s (soldering iron , 1 time ) ? soldering should be at a distance of at least 1.5 mm from the body of the products. electrostatic discharge ? when handling the products, the operator must be grounded. grounded wrist straps worn should have at least 1m of resistance from the operator to ground to prevent shock hazard, and it should be placed near the operator. ? workbenches where the products are handled should be grounded and be provided with conductive table and floor mats. ? when using measuring equipment such as a curve tracer , the equipment should be grounded. ? when soldering the products, the head of soldering irons or the solder bath must be grounded in order to prevent leak voltages generated by them from being applied to the products. ? the products should always be stored an d transported in sanken shipping containers or conductive containers, or be wrapped in aluminum foil.
str - a6000 series str - a6000 - ds rev .4. 3 sanken electric co.,ltd. 28 m ar . 1 3 , 2 01 5 important notes ? the contents in this document are subject to changes, for improvement and other purposes, without notice. make sure that this is the latest revision of the document before use. ? application examples, operation examples and r ecommend ed example s described in this document are quoted for the sole purpose of reference for the use of the products herein and sanken can assume no responsibility for any infringement of industrial property rights, intellectual property rights , life , body, property or any other rights of sanken or any third party which may result from its use. ? unless otherwise agreed in writing by sanken, sanken makes no warranties of any kind, whether express or implied, as to the products, including product merchantability, and fitness for a particular purpose and special environment, and the information, including its accuracy, usefulness, and reliability, included in this docume nt. ? although sanken undertakes to enhance the quality and reliability of its products, the occurrence of failure and defect of semiconductor products at a certain rate is inevitable. users of sanken products are requested to take, at their own risk, preven tative measures including safety design of the equipment or systems against any possible injury, death, fires or damages to the society due to device failure or malfunction. ? sanken products listed in this document are designed and intended for the use as c omponents in general purpose electronic equipment or apparatus (home appliances, office equipment, telecommunication equipment, measuring equipment, etc.). when considering the use of sanken products in the applications where higher reliability is require d (transportation equipment and its control systems, traffic signal control systems or equipment, fire/crime alarm systems, various safety devices, etc.), and whenever long life expectancy is required even in general purpose electronic equipment or apparat us, please contact your nearest sanken sales representative to discuss, prior to the use of the products herein. the use of sanken products without the written consent of sanken in the applications where extremely high reliability is required (aerospace eq uipment, nuclear power control systems, life support systems, etc.) is strictly prohibited. ? when using the products specified herein by either (i) combining other products or materials therewith or (ii) physically, chemically or otherwise processing or tre ating the products, please duly consider all possible risks that may result from all such uses in advance and proceed therewith at your own responsibility. ? anti radioactive ray design is not considered for the products listed herein. ? sanken assumes no resp onsibility for any troubles, such as dropping products caused during transportation out of sankens distribution network. ? the contents in this document must not be transcribed or copied without sankens written consent.

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