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rev. 1.30 1 june 26, 2015 rev. 1.00 pb june 26, 2015 HT7L4811 non-isolation buck led lighting driver with active pfc features ? tiny package sot23-6 ? non-isolation buck topology ? low bom cost ? wide ac input range C from 85v ac to 265v ac ? high power factor of >0.9 without additional circuitry ? accurate constant current (< 3%) ? low start-up current which reduces power dissipation ? full protection functions for enhanced safety ? gate driver output voltage clamp ? vcc over voltage protection (vcc ovp) ? vcc under-voltage lockout with hysteresis (vcc uvlo) ? output led string over current protection ? output led string short protection ? output led string open protection ? on-chip over temperature protection (otp) applications ? general illumination ? e26/27, t5/t8 led lamp ? other led lighting applications general description the HT7L4811 is a non-isolation buck pwm controller for led lighting applications. the device has a fully integrated pfc c ircuit whi ch operat es i n a bounda ry conduction mode (bcm) to achieve high power factor values. w ith good control over external mosfet s, the device can easily meet exacting led current and high power factor requirements. the ht7l481 1 provides several protection functions, which include vcc under v oltage lockout (uvlo), over current prot ection (ocp), out put l ed string open protection, output led string short protection, vcc over v oltage protection (ovp) and leading-edge bl anking (l eb) for c urrent se nsing. additionally and to ensure system reliability , the device i ncludes a fu lly i ntegrated t hermal p rotection function. t o prot ect t he e xternal powe r mosfet from being damaged by a supply over voltage, the device drv pin voltage is clamped to about 17v. the high level of functional integra tion minimises the external component count giving major advantages in terms of cost and circuit board area. the device is supplied in a sot23-6 package.
rev. 1.30 2 june 26, 2015 HT7L4811 block diagram 0.2v cs comp zcd starter min off time drv ea pwm generator ocp zcd comparator uvlo vcc reference & bias zcd ovp otp logic control driver leb gnd vcc ovp pin assignment comp cs zcd drv gnd top view sot23-6 vcc l4811 pin description pin no. symbol description 1 vcc power supply pin 2 gnd ground pin 3 drv gate drive output for driving external power mosfets 4 zcd zero-current detect pin 5 cs current sense pin. a resistor is connected to sense the mosfet current. 6 comp loop compensation pin. a capacitor is placed between comp and gnd.
rev. 1.30 3 june 26, 2015 HT7L4811 electrical characteristics v cc =18v, ta=25c symbol parameter test condition min typ max unit power supply (vcc pin) vcc on uvlo on 18 v vcc off uvlo off 10 v vcc hys uvlo hysteresis 7 v v ovp vcc ovp trip point 26 29 32 v i start start-up current before turn-on, @ v cc = uvlo on - 1v 10 20 a i q quiescent current no switching 0.6 1 ma i cc operating current @ 70khz, co=1nf 1.8 2.5 ma error amplifer v fb feedback reference voltage t a = 25c 194 200 206 mv current sense comparator t leb leading edge blanking time 400 ns v cl current limit threshold 1.3 v v ocp over current trip point 0.9 v over current release point 0.2 v zero current detector v zcdh upper clamp voltage i zcd = 300a 3 v v zcdl lower clamp voltage i zcd = -2.5ma -0.2 v v zcda positive-going edge 1.5 v v zcdt negative-going edge 1 v i ovp ovp current on zcd pin 270 300 330 a t b_ovp blanking time for ovp detection 1 s starter t start start timer period 40 s t off minimum off time 4 s over t emperature protection otp over temperature trip point 150 c absolute maximum ratings 9 vsso rowdh 9 wr 9 ,sw rowdh wr 6 sl 9 wr 9 2wsw rowdh dw 203 sl 9 wr 9 0dlpp fuuhw dw sl p vrufh p vln 0dlpp rshudwl mfwlr whpshudwuh 6wrudh whpshudwuh udh wr recommended operating ranges 9 vsso rowdh 9 wr 9 2shudwl mfwlr whpshudwuh wr 1rwh 7hv h duh v wuhvv udwlv ro 6 wuhvvhv hfhhgl wh udh v shflhg ghu evrowh 0 dlpp 5dwlv pd fdvh vevwdwldo gdpdh wr wh ghlfh )fwlrdo rshudwlr ri wlv ghlfh dw rwhu frglwlrv ehrg wrvh o lvwhg l w h vs hflfdwlr l v rw l psolhg d g s urorhg h srvuh w r h wuhph f rglwlrv p d d iihfw ghlfh uholdelolw
rev. 1.30 4 june 26, 2015 HT7L4811 symbol parameter test condition min typ max unit gate driver t r rising t ime c load =1nf, 10%~90% 85 ns t f falling time c load =1nf, 10%~90% 50 ns i source source current 220 ma i sink sink current 250 ma v g_clamp gate clamp voltage @ v cc = 25v 16 19.5 v typical performance characteristics 4 6 8 10 12 14 16 -40 -20 0 20 40 60 80 100 120 temperature ( ) start up current (ua) figure 1. start-up current vs. temperature 1.6 1.65 1.7 1.75 1.8 1.85 1.9 1.95 2 -40 -20 0 20 40 60 80 100 120 temperature ( ) operating current (ma) figure 2. operation current vs. temperature 17 17.4 17.8 18.2 18.6 19 -40 -20 0 20 40 60 80 100 120 temperature ( ) uvlo_on(v) figure 3. uvlo_on vs. temperature
rev. 1.30 5 june 26, 2015 HT7L4811 9 9.4 9.8 10.2 10.6 11 -40 -20 0 20 40 60 80 100 120 temperature ( ) uvlo_off(v) figure 4. uvlo_off vs. temperature 198 198.5 199 199.5 200 200.5 201 -40 -20 0 20 40 60 80 100 120 temperature ( ) vfb (mv) figure 5. vfb vs. temperature 160.00 160.50 161.00 161.50 162.00 162.50 163.00 9s 10s 11s 12s 13s ac input (vac) iout (ma) 90vac 100vac 115vac 135vac 180vac 220vac 240vac 265vac figure 6. iout vs. led(s) regulation in e27 bulb
rev. 1.30 6 june 26, 2015 HT7L4811 160.00 160.50 161.00 161.50 162.00 162.50 163.00 90 100 115 135 180 220 240 265 ac input (vac) iout (ma) 9s (162ma) 10s (162ma) 11s (162ma) 12s (162ma) 13s (162ma) figure 7. iout vs. wide ac voltage in e27(8w, 13s / 162ma) bulb 80.0% 81.0% 82.0% 83.0% 84.0% 85.0% 86.0% 87.0% 88.0% 89.0% 90 100 115 135 180 220 240 265 ac input (vac) efficiency 9s (162ma) 10s (162ma) 11s (162ma) 12s (162ma) 13s (162ma) figure 8. effciency vs. wide ac voltage in e27(8w, 13s / 162ma) bulb 0.800 0.820 0.840 0.860 0.880 0.900 0.920 0.940 0.960 0.980 1.000 90 100 115 135 180 220 240 265 ac input (vac) power factor (pf) 9s (162ma) 10s (162ma) 11s (162ma) 12s (162ma) 13s (162ma) figure 9. power factor (pf) vs. wide ac voltage in e27(8w, 13s / 162ma) bulb 410 411 412 413 414 415 416 417 418 419 420 led 10s led 11s led 12s led 13s led 14s led(s) iout(ma) 90vac 100vac 115vac 135vac 180vac 220vac 240vac 265vac figure 10. iout vs. led(s) regulation in t8 tube
rev. 1.30 7 june 26, 2015 HT7L4811 410 411 412 413 414 415 416 417 418 419 420 90 100 115 135 180 220 240 265 ac input (vac) iout (ma) led 10s led 11s led 12s led 13s led 14s figure 11. iout vs. wide ac voltage in t8 (18w, 12s / 425ma*) tube 80 81 82 83 84 85 86 87 88 89 90 100 115 135 180 220 240 265 ac input (vac) efficiency (%) 10s,414ma 11s,414ma 12s,414ma 13s,414ma 14s,414ma figure 12. effciency vs. wide ac voltage in t8(18w, 12s / 425ma) tube 0.840 0.860 0.880 0.900 0.920 0.940 0.960 0.980 1.000 90 100 115 135 180 220 240 265 ac input (vac) pf 10s,414ma 11s,414ma 12s,414ma 13s,414ma 14s,414ma figure 13. power factor (pf) vs. wide ac voltage in t8(18w, 12s / 425ma) tube
rev. 1.30 8 june 26, 2015 HT7L4811 0 5 10 15 20 25 90 100 115 135 180 220 240 264 ac input (vac) thd(%) e27 8w (13s, 162ma) t8 18w (12s, 425ma) figure 14. e27/t8 thd vs. wide ac voltage note: * 425ma is typical current limit. actual led current will be variable due to sense resistor tolerance. typical application circuit 90vac ~ 265vac led+ led - drv gnd vcc zcd cs comp HT7L4811 application information the ht7l481 1 is a universal ac/dc led driver designed for led lighting applications. the device can achieve high power factor values without resorting to additional circuits and can also generate high accuracy led drive currents with very few external components. separate grounds are provided; one is a foating ground for the h t7l4811 w hile the other one is the earth. users should be aware that the two grounds cannot be directly connected together to avoid ic damage and system malfunction. start-up current a very low start-up current, ist art, allows the users to se lect a l arger va lue of st art-up re sistor whi ch reduces power dissipation. vcc under voltage lockout C uvlo the device includes a uvlo feature which has 8 v hysteresis. the pwm controller turns on when vcc is higher than 18v and turns of f when vcc is lower than 10v . the h ysteresis characteristics guarantee that the device can be powered by an input capacitor during start-up. when the output voltage increases to a certain value after start -up , vcc will be char ged by an output through an auxiliary winding or a zener diode. v z =v led - v cc .
rev. 1.30 9 june 26, 2015 HT7L4811 boundary conduction mode C bcm the power mosfet is turned on by inductor current zero-crossing detection. the current zero-crossing can be detected by a zcd voltage. when the inductor current i s a t t he z ero c rossing poi nt, t he vol tage on the zcd pin will drop rapidly . the ht7l481 1 then de tects t he fa lling e dge a nd t urns on t he powe r mosfet. t he bounda ry c onduction m ode provi des low t urn-on swi tching l osses a nd hi gh c onversion effciency. zero current detection C zcd the z cd vol tage i s de signed t o ope rate be tween 0v and 3v for normal operation. if the voltage on the zcd pin goes higher than 1.5v , the zcd comparator waits unt il the vol tage goes below 1v . when the inductor current is at the zero crossing point, the voltage on the zcd pin will drop rapidly . the device will then detect the 1v falling edge and turn on the power mosfet. the 0.5v hysteresis avoids any false triggering actions due to noise. constant current control the ht7l481 1 will sense the overall inductor current and form a closed-loop with an internal error amplifier to obtain high constant current accuracy . the cs voltage and the 0.2v reference voltage are the inputs of a gm amplifier whose output is integrated via an external comp capacitor . the on time of the mosfet is controlled by the comp voltage to adjust the output current. leb on cs C leading-edge blanking each time the external power mo sfet is sw itched on, a t urn-on spi ke wi ll i nevitably occ ur at t he se nse resistor. t o avoid faulty triggering, a 400ns leading- edge blank time is generated. as this function is provided conventional rc filtering is therefore unnecessary. during this blanking period, the current- limit comparator is disabled and can therefore not switch off the gate driver. gate driver clamp the dr v pi n i s c onnected t o t he ga te of e xternal mosfet to control its on/off function. t o protect the external pow er mos fet from being over - stressed, the gate driver output is clamped to 17v. ovp on vcc C over voltage protection in order to prevent pwm controller damage, the device includes an ovp function on vcc. should the vc c v oltage b e h igher t han t he ovp t hreshold voltage of 29v , the pwm controller will stop operating immediately . when the vcc voltage decreases be low t he uvl o of f l evel, t he c ontroller will reset. led open protection C zcd ovp the led voltage is reflected on the zcd pin through a resistor rzcd. when the current on the resistor rzcd is higher than 300a, then zcd ovp protection will take place. here the pwm controller will stop operating immediately . when the v cc voltage decreases below the uvlo of f level, the controller will reset. v ovp-zcd can be set using the following equation : v ovp?zcd = v zcdh + i ovp r zcd t he v zcdh is the upper clamp voltage 3v on the zcd pin . t he i ovp represents the ovp current level on the zcd pin which is 300 a. t he r zcd stands for the resistor connected between the zcd pin and the led positive terminal. ocp C over current protection the ht 7l4811 i ncludes a n o ver c urrent p rotection function on the cs pin. an internal circuit detects the current level and when the current is lar ger than the o ver c urrent p rotection thres hold level , v ocp /r cs , the gate output will remain at a low level. led short protection C scp the output voltage drops when a number of leds in a st ring a re sho rted re sulting i n a vol tage drop a t vcc. onc e t he vcc drops be low 10v , t he de vice will stop operating. under such situations, the start-up operation will rechar ge the vcc pin through the start- up resistor and the device will enter the uvlo hiccup mode. thermal protection a t hermal p rotection f eature i s i ncluded t o p rotect the device from excessive heat damage. when the junction temperature exceeds a threshold of 150c, the thermal protection function will turn of f the dr v terminal immediately . when the vcc decreases below the uvlo off level, the controller will reset.
rev. 1.30 10 june 26, 2015 HT7L4811 package information note that the package information provided here is for consultation purposes only. as this information may be updated at regular intervals users are reminded to consult the holtek website for the latest version of the package/ carton information . additional supplementary information with regard to packaging is listed below. click on the relevant section to be transferred to the relevant website page. ? package information (include outline dimensions, product tape and reel specifcations) ? the operation instruction of packing materials ? carton information
rev. 1.30 11 june 26, 2015 HT7L4811 6-pin sot23-6 outline dimensions symbol dimensions in inch min. nom. max. a 0.057 a1 0.006 a2 0.035 0.045 0.051 b 0.012 0.020 c 0.003 0.009 d 0.114 bsc e 0.063 bsc e 0.037 bsc e1 0.075 bsc h 0.110 bsc l1 0.024 bsc 0 8 symbol dimensions in mm min. nom. max. a 1.45 a1 0.15 a2 0.90 1.15 1.30 b 0.30 0.50 c 0.08 0.22 d 2.90 bsc e 1.60 bsc e 0.95 bsc e1 1.90 bsc h 2.80 bsc l1 0.60 bsc 0 8
rev. 1.30 12 june 26, 2015 HT7L4811 copyright ? 2015 by holtek semiconductor inc. the information appearing in this data sheet is believed to be accurate at the time of publication. however, holtek assumes no responsibility arising from the use of the specifcations described. the applications mentioned herein are used solely for the purpose of illustration and holtek makes no warranty or representation that such applications will be suitable without further modification, nor recommends the use of its products for application that may present a risk to human life due to malfunction or otherwise. holtek's products are not authorized for use as critical components in life support devices or systems. holtek reserves the right to alter its products without prior notifcation. for the most up-to-date information, please visit our web site at http://www.holtek.com.tw.

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