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ld9704r 03 / 15 /201 7 1 leadtrend technology corporation www.leadtrend.com.tw ld9704r - d s - 00 march 2017 green - mode pwm controller with frequency swapping with protections a nd mosfet integrated r ev . 0 0 general description the ld9704 r is built - in with several functions, protection and emi - improved solution within a 68 0v mo sfet in a dip - 6 package. it takes les s components counts or circuit space, especially ideal for those total solutions of low cost. the implemented functions include low startup current, green - mode power - saving operation and internal slope compensation . it also features more protections like olp (over load protection) and ovp (over v o ltage protection) to prevent circuit damage occurred under abnormal condi tions. furthermore, the f requency s wapping function can reduc e the noise level and thus help the power circuit designers to easily deal wit h the emi filter design by spending minimum amount of component cost and developing time. feature s ? built - in 680 v power mosfet ? fixed switching frequency at 13 0khz ? very low startup current (< 3 ? a) ? current mode control ? green mode control ? uvlo ( under voltage lockout ) ? inter nal frequency swapping , slop e compensation ? ovp (over voltage protection) on vcc pin ? built in ocp(over current protection) compensation ? otp (over temperature protection) through a ntc ? olp (over load protection) applications ? switching ac/dc adaptor and battery charger ? open frame switching power supply typical application e m i f i l t e r o t p d r a i n c s v c c g n d c o m p l d 9 7 0 4 r p h o t o c o u p l e r a c i n p u t d c o u t p u t
ld9704r 0 3 / 15 /201 7 2 leadtrend technology co rporation www.leadtrend.com.tw ld9704r - d s - 00 match 201 7 pin configuration order ing information part number package t op mark shipping LD9704RGP7 dip - 6 LD9704RGP7 36 00 /tube /carton the ld9704r is rohs compliant / green packaged protection mode switching freq. olp vcc ovp otp pin output short 130k hz auto recover y auto recover y latch auto - restart by olp pin descriptions dip - 6 name function 1 otp pull this pin bel ow 0.95v to shut down the controller into latch mode until the ac resume s power - on. connecting this pin to ground with ntc will achieve otp protection. let this pin float or connect a 100k ? resistor to disable the latch protection. 2 comp voltage feedback pin . c onnect a photo - coupler to close the control loop and achieve the regulation. 3 gnd ground 4 c s source terminal of the internal power mosfet and current sense pi n 5,6 drain drain terminal of the internal power mosfet 7 nc nc 8 vcc supply voltage pin yy: year code ww: week code pp: production code 1 8 2 3 4 6 5 top mark yywwpp yywwpp otp comp gnd c s vcc drain dip - 6 (top view)
ld9704r 0 3 / 15 /201 7 3 leadtrend technology co rporation www.leadtrend.com.tw ld9704r - d s - 00 match 201 7 block diagram i n t . o s c c o m p c s d r a i n i n t e r n a l b i a s & v r e f p w m c o m p a r a t o r v u v l o ( o n ) / v u v l o ( o f f ) g r e e n - m o d e c o n t r o l 1 . 5 r r r s q p g s l o p e c o m p e n s a t i o n v c c v c s _ o f f v c o m p _ o l p o c p c o m p a r a t o r o l p c o m p a r a t o r p r o t e c t i o n o v p u v l o c o m p a r a t o r d r i v e r s t a g e o v p c o m p a r a t o r p r o t e c t i o n p g v c o m p _ o p e n o l p v b i a s g n d o t p p g i n t . o t p s h u t d o w n l o g i c o v p l e a d i n g e d g e b l a n k i n g o l p d e l a y c o u n t e r v c c - o v p + - i n t . o t p 1 0 0 u a 1 . 0 5 v / 0 . 9 5 v + - e x t . o t p v b i a s v c s v c s p d r q q s e t c l r s r p g p r o t e c t i o n / l a t c h v g , c l a m p = 1 3 v ?
ld9704r 0 3 / 15 /201 7 4 leadtrend technology co rporation www.leadtrend.com.tw ld9704r - d s - 00 match 201 7 absolute maximum ratings supply voltage vcc - 0.3 v ~ 30 v comp, c s , otp - 0.3 v ~ 6 v drain - 0.3v ~ 680v avalanche energy (l=10mh , ias=3a ) on absolute maximum ratin g) 45mj maximum junction temperature 150 ? c storage temperature range - 6 5 ? c ~ 1 50 ? c p ackage thermal resistance (dip - 6 /7 , ja ) 80 ? c /w pa ckage thermal resistance (dip - 6 /7 , jc ) 30 ? c /w power dissipation (dip - 6 /7 , at ambient temperature = 25 ? c ) 125 0mw lead temperature (soldering, 10sec) 26 0 ? c esd voltage protection, human body model (drain pin is exclusive) 2.5 kv esd voltage protection, machine model (drain pin is exclusive) 25 0 v caution: stress exceeding maximum ratings may damage the device. maximum ratings are stress ratings only. functional operation above the recommended operating conditions is not implied. extended exposure to stress above recommended operating conditions may affect device reliability recommended operating conditions note : 1. it s essential to connect vcc pin with a smd ceramic capacitor (0.1 ? f ~ 0.47 ? f) to filter out the undesired switching noise for stable operation. this capacitor should be placed close to ic pin as possible 2. it s also essential to connect a capacitor to co mp to filter out the undesired switching noise for stable operation. 3. the small signal components should be placed close t o ic pin as possible. item min. max. unit operating junction temp erature - 4 0 12 5 ? c supply v cc voltage 8 .5 26.5 v vcc capacitor 4.7 10 ? f start - up resistor value (ac side, half wave) 750k 2.4 m ? comp pin capacitor 1 10 nf current sense i mpedance 0.52 - snubber capacitor between drain and cs pin - 100 pf
ld9704r 0 3 / 15 /201 7 5 leadtrend technology co rporation www.leadtrend.com.tw ld9704r - d s - 00 match 201 7 electrical characteristics (t a = +25 ? c unless otherwise stated, vcc =15.0v) parameter conditions sym. min typ max units supply voltage ( vcc pin) startup current vcc < uvlo(on) i cc_ st 1.5 3 ? comp = 3 v i cc_ op1 2.5 3. 5 ma v comp =0v i cc_ op2 0. 35 0. 5 ma olp/ovp tripped / auto i c c_ opa 600 ? cc_ opl1 4 3 0 500 ? cc_ opl2 4 0 60 ? cc _p dr 3. 6 4. 5 5. 2 v uvlo(off) out off v cc _ off 7.0 7.5 8.0 v uvlo(on) v cc _ o n 15 16 17 v vcc ovp level v cc _ o vp 2 8.5 v vcc ovp de - bounce time * t d _ vcc ovp 8 cycle voltage feedback (comp pin) short circuit current v comp =0v i comp 0.125 m a open loop voltage comp pin open v comp_open 2.75 3 3 .25 v normal mode threshold *; comp pin v n 1.2 v green mode threshold *; comp pin v g 1 v zero duty threshold vcomp v zdc 0.6 v zero duty hysteresis v zdch 100 mv current sensing ( c s pin) maximum input voltage, v s_off *; duty=50% v cs_ 50% 0. 6 0 v maximum input voltage, v s_off duty=2 5 % v cs_2 5 % 0. 50 v min. on time * t leb 400 ns internal limited vcs level * ; when v cs >v cs,limit , gate off immediately v cs_ limit 1.2 v internal slope compensation * *; 0% to d max . (linearly increase) v slp_ l 3 00 mv input impedance * z cs 1 m ? pd 100 n s soft start duratio n * t ss 7 ms
ld9704r 0 3 / 15 /201 7 6 leadtrend technology co rporation www.leadtrend.com.tw ld9704r - d s - 00 match 201 7 (t a = +25 ? c unless otherwise stated, vcc =15.0v) parameter conditions sym. min typ max units oscillator for switching frequency frequency, freq f sw 120 1 30 140 khz green mode frequency, fre qg f sw_ green 28 khz frequency swapping v comp > 2.575 v f sw_ mod ? sw_ ts 0 5 % voltage stability * *; ( vcc =11v - 25v) f sw_ vs 0 1 % max. duty mxd 80 % olp (over load protection) olp t r ip level v comp_olp 2.6 v olp delay time at start - up* olp + soft start t d_olpss 71.5 ms otp pin latch protection (otp pin) otp pin source current i otp 9 0 100 1 10 ? otp_on 1.0 1.05 1.1 v otp turn - off trip level v otp_off 0.9 0.95 1.0 v otp turn - off trip resistance *; v otp _off /i otp r otp 9.5 k ? comp > 3 v t d_ otp 500 ? internal otp protection otp level * t up_ otp 14 0 inotp _hys 15 electrical characteristics for mosfet (t a = +25 o c ) parameter conditions symbol min typ max units drain to source breakdo wn voltage breakdown voltage bv dss vcc=0v, comp=0v, i d = 250 ? dss 680 v drain current continuous drain current *; vcc=15v, comp= 2 v i d 3 a drain on resistance d to s pin on - resistance i d = 1.5 a;v cc =1 5 v; r dson 2.4 2.8 ? * : g uaranteed by design.
ld9704r 0 3 / 15 /201 7 7 leadtrend technology co rporation www.leadtrend.com.tw ld9704r - d s - 00 match 201 7 typical performance characteristics
ld9704r 0 3 / 15 /201 7 8 leadtrend technology co rporation www.leadtrend.com.tw ld9704r - d s - 00 match 201 7
ld9704r 0 3 / 15 /201 7 9 leadtrend technology co rporation www.leadtrend.com.tw ld9704r - d s - 00 match 201 7 application information operation overview th e l9704r meets the green - power requirement with a 680 v mosfet driver an d is intended for the use in those modern switching power suppliers and adaptors which demand higher power efficiency and power - saving. it integrated more functions to reduce the external components counts and the size. its major features are described as below. under voltage lockout (uvlo) an uvlo comparator is implemented in it to detect the voltage on the vcc pin. it would assure the supply voltage enough to turn on the ld9704r pwm controller and further to drive the power mosfet. as shown in fig. 1 1 , a hysteresis is built in to prevent the shutdown from the voltage dip during startup. fig. 1 1 startup current and startup circuit the typical startup circuit to generate vcc of the ld9704r is shown in fig. 12 . during the start up transient, the vcc is below uvlo threshold . before it has sufficient voltage to develop out pulse to operation , r1 will provide the startup current to charge the capacitor c1. once vcc obtain enough voltage to turn on the ld9704r and it s working condi tion , it will enable the auxiliary winding of the transformer to provide supply current . lower startup current requirement on the pwm controller will help to increase the value of r1 and then reduce the power consumption on r1. by using cmos process and t he special circuit design, the maximum startup current for ld9704r is under 3 ? a. if a higher resistance value of the r1 is chosen, it will usually take more time to start up. to carefully select the value of r1 and c1 will optimize the power consumpti on a nd startup time. fig. 12 current sensing and leading - edge blanking the typical current mode of pwm controller feedbacks both current signal and voltage signal to close the control loop and achieve regulation. the ld 97 04 r de tects the internal mosfet current from the c s pin and pulse - by - pulse lim i t ed current. the maximum voltage threshold of the cur rent sensing pin is vcs_off . due to integrated leading edge blanking circuit and internal spike filter , t he mosfet peak current c an be obtain ed from the equation as follows: vcc uvlo ( on ) uvlo ( off ) t t i ( vcc ) operating current ( ~ ma ) startup current ( ~ a ) e m i f i l t e r r 1 d r a i n c s v c c g n d l d 9 7 0 4 r a c i n p u t c 1 c b u l k d 1 s off cs max peak r v i _ ) ( ?
ld9704r 03/15 /201 7 10 leadtrend technology co rporation www.leadtrend.com.tw ld9704r - d s - 00 match 201 7 in general, the power mosfet peak current is various in corresponding to ac input v oltage. to compensate it, ld 9704r will change the current limit vcs_off with the duty cycles. p lease refer to fig. 13 fig. 1 3 voltage feedback loop the voltage feedback signal is provided from the tl431 at the secondary side through the photo - coupler to the c omp pin of th e ld 9704 r. it would carry a diode voltage offset at the stage to feed the voltage divider at the ratio, th at is, a pull - high resistor is embedded internally and can be eliminated externally. oscillator and switching frequency the ld9704r is implemented with frequency swapping function which helps the power supply designers to both opti mize emi performance and lower system cost. the switching frequency substantially centers at 130 khz, and swap between a range of 6 khz. green - mode operation by using the green - mode control, the switching frequency can be reduced under the light load condit ion . t his feature helps to improve the efficiency in light load conditions. the green - mode control is leadtrend technology s own property . p lease refer to fig. 14 fig. 14 on/off control the ld 9704 r can be turned off by pulling comp pin lowe r than 0.6 v. th e drain pin of the ld 9704 r will be disabled immediately u nder such condition. the off - mode can be released when the pull - low signal is removed. internal slope compensation in the conventional application s , the problem of the stability is a critical issue for current mode controlling, when it operates over 50% duty - cycle. as uc384x, it takes slope compensation from injecting the ramp signal of the rt/ct pin through a coupling capacitor. it therefore requires no extra design for the ld9704r since it has int egrated it already. over load protection (olp) - auto recovery to protect the circuit from damage in over - load condition and short or open - loop condition, the ld 9704r is implemented with smart olp function. it also features au to recovery function; see fig. 15 for the waveform. in case of fault condition, the feedback system will force the voltage loop toward the saturation and then pull the voltage high on comp pin (vcomp). when the v comp ramp s up to the olp threshold of 2 .6 v and continues over olp delay ti me, the protection will ) ( 5 . 1 ) ( comp pwm v r r r v comparator ? ? ? ? v c s _ o f f ( v ) 5 0 % 2 5 % d u t y 0 . 6 0 v 0 . 5 0 v 0 . 8 0 v 8 0 % v c o m p 1 . 2 v 0 . 6 v f s 1 v 1 3 0 k h z 2 8 k h z
ld9704r 03/15 /201 7 11 leadtrend technology co rporation www.leadtrend.com.tw ld9704r - d s - 00 match 201 7 be activated and then turn off the gate output to stop the switching of power circuit. with the protection mechanism, the average input power will be minimized to remain the component temperature and stress within the safe operating area. fig. 15 over voltage protection (ovp) on vcc - auto recovery t he vcc ovp function of ld 9704 r is in auto recovery mode. as soon as the voltage of the vcc pin ri ses above ovp threshold, the output gate drive circuit will be shutdown simultaneous to turn off the power mosfet. mosfet characteristic the mos fet is divided into three operation regions, ohmic region, saturation region, and the cut - off region, shown as fig. 16 . for switching power supply applications, it shall operate in ohmic and cut - off region. never reach the region of saturation; it would cause damage for acting beyond the maximum safety operating area. it s necessary to check the characteristic of mosfet. fig. 16 otp pin --- la tched m ode protection the otp circuit is implemented to sense whether there is any hot - spot of power circuit like power mosfet or o utput rectifier. once an over - temperature condition is detected, the otp is enabled to shut down the controller to protect th e controller. typically, a ntc is recommended to connect with otp pin. the ntc resistance will decrease as the device or ambient in high temperature. the relationship is as below. v otp =100 a x r ntc when the votp is lower than the defined voltage thresh old (typ. 0.95v), the ld 9704 r will shut down the gate output and latch off the power supply. there are 2 conditions required to restart it successfully. first, cool down the circuit so that ntc resistance will increase and raise v otp up above 1.05v. then, remove the ac power cord and re - plug ac power. layout guide f or pcb layout, please check spike on c s pin. t his measurement method is between gnd and c s pin to check positive and negative voltage . s uggest vcs spike must be is under 0.2v at minimum load and 0.6v at full load after leb time (~300ns) . moreover, check negative voltage is not still lower than - 2v in 200ns time continued . v c c u v l o ( o n ) u v l o ( o f f ) t t c o m p o l p o l p t o u t o l p d e l a y t i m e s w i t c h i n g s w i t c h i n g n o n - s w i t c h i n g o l p t r i p l e v e l u v l o ( o f f ) o l p r e s e t vds id ohmic region saturation region vgs 1 vgs 2 vgs 3 vgs 4 vgs 5 vgs 5 > vgs 4 > vgs 3 > vgs 2 > vgs 1 cut - off region
ld9704r 03/15 /201 7 12 leadtrend technology co rporation www.leadtrend.com.tw ld9704r - d s - 00 match 201 7 fig. 17 c s v c c g n d l d 9 7 0 4 r o u t ( 4 ) ( 2 ) ( 1 ) ( 3 ) l a y o u t g u i d e ( 4 ) ? ( 3 ) ? ( 2 ) ? ( 1 ) t h e n e g a t i v e s p i k e e x c e e d s - 2 . 0 v i n 2 0 0 n s c o n t i n u e d t h i s s p i k e v o l t a g e i s l o w e r t h a n v c o m p 8 / 4 a f t e r l e b p e r i o d .
ld9704r 03/15 /201 7 13 leadtrend technology co rporation www.leadtrend.com.tw ld9704r - d s - 00 match 201 7 package information dip - 6 dimension in millimeters dimen sions in inches symbol min max min max a 9.017 10.160 0.355 0.400 b 6.100 6.600 0.240 0.260 c 3.300 4.320 0.130 0.170 d 0.356 0.584 0.014 0.023 e 1.143 1.778 0.045 0.070 f 2.480 2.600 0.098 0.102 h 3.170 3.600 0.125 0.142 i 2.921 3.810 0.115 0.150 j 7.366 7.874 0.290 0.310 k 0.246 0.305 0.010 0.012 l 0.381 0.540 0.015 0.021 m 7.493 8.255 0.295 0.325 p 2.920 3.100 0.115 0.122 s 6.273 6.427 0.247 0.253 i mportant notice leadtrend technolo gy inc. reserves the right to make changes or corrections to its products at any time without notice. customers should verify the datasheets are current and complete before placing order. s
ld9704r 03/15 /201 7 14 leadtrend technology co rporation www.leadtrend.com.tw ld9704r - d s - 00 match 201 7 r e vision history rev . d a te change notice 00 03/15 /201 7 original specification .

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