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rev. 1.20 1 march 12, 2013 rev. 1.00 pb march 12, 2013 ht7l4091 universal step-down pwm control for high brightness led lighting control features ? input supply ac voltage range: 100v~240v ? ultra low power-on start-up current < 30a ? integrated 25v zener diode internally connected to vin pin ? 5v ldo output voltage with 6ma driving current for external components ? frequency jitter function for enhanced emi performance ? effciency > 85% ? under v oltage lockout function C uvlo ? current mode operation with cycle-by-cycle current limiting ? over temperature protection function ? high-current fet drive output ? linear and pwm dimming function ? enhanced short circuit protection function applications ? ac/dc and dc/dc power control for high power led lighting ? rgb back lighting led driver ? flat panel displays back lighting ? general purpose constant current source ? signage and decorative led lighting ? battery chargers general description the ht7l4091 device provides a low-cost solution for active current mode pwm controls of h igh intensity led drive systems supplied by either ac or dc line power lines. the device operates in constant off-time mode which is suitable for buck led drivers. the low start-up and operat ing currents provides fexible power requirements for high effciency or low cost a pplications. t he swi tch fre quency of f-time c an be programmed using an external resistor . the peak current mode control achieves good output current regulation without requiring loop compensations for a wide range of input voltages. included i n t he d evice i s a pw m d imming i nput which ca n ac cept an exte rnal control si gnal wit h a duty ratio from 0 to 100%. the output current can be programmed from 0 to 250ma by applying an external control voltage on the linear dimming control input. the device includes a frequency jit ter function which helps to reduce emi power supply emissions. also contained is an enhanced led short circuit protection feature t o prot ect t he i nternal c ircuitry from da mage should the leds be short circuited. the device requires a minimum number of external standard compone nts and is available in an 8-pin sop package for small area pcb applications. ordering information part number function description ht7l4091 frequency jitter function enabled, v uvlo(h) =16v (typ.) ht7l4091-1 frequency jitter function disabled, v uvlo(l) =8v (typ.)
rev. 1.20 2 march 12, 2013 ht7l4091 block diagram ldo blank otp r s q pwmd 0.25v cs pdm vin gdr gnd 25v vdd rt 0.5v qb r s q qb ld 100k osc (jitter) power on reset uvlo on pin assignment vin cs gnd gdr rt ld vdd pdm ht7l4091 8 sop-a 1 2 3 4 8 7 6 5 pin description pin name i/o description vin i input voltage pin cs i led string current sense input gnd power ground gdr o gate driver for the external mosfet pdm i pwm dimming pin also functions as enable input pin. vdd o positive power supply used for the internal circuits except the gate driver circuit. a 0.1f capacitor must be connected between the vdd and the gnd pins. ld i linear dimming pin set the current sense threshold as long as the voltage on this pin is less than 250mv (typ.). rt i oscillator control pin a resistor is connected between the rt and the gnd pins to set the off-time.
rev. 1.20 3 march 12, 2013 ht7l4091 absolute maximum ratings output current peak ............................................... 1a storage t emperature range ............... -65c ~ +150c junction t emperature range .............. -40c ~ +150c cs, p dm , ld ,rt, to gnd .......... -0.3v to (v dd +0.3v) power dissipation at t a<25c ............................. 0.6w thermal resistance, sop-8 ja ..................... 150c/w esd v oltage protection, human body model ...... 6kv esd v oltage protection, machine model ............ 400v note: these are stress ratings only . stresses exceeding the range specifed under absolute maximum ratings may cause substantial damage to the device. functional operation of this device at other conditions beyond those l isted i n t he sp ecifcation i s n ot i mplied a nd p rolonged e xposure t o e xtreme c onditions m ay a ffect device reliability. recommended operating ranges input supply v oltage .................. v uvlo(h) +0.1v~v clamp operating t emperature range ........... -40c ~ +105c note 1: absolute maximum ratings indicate limits beyond which damage to the device may occur . operating ratings indicate conditions for which the device is intended to be functional, but do not guarantee specifc performance limits. the guaranteed specifcations apply only for the test conditions listed. note 2: the power supply pin should not be driven by a dc, low impe dance power source greater than the v clamp voltage specifed in the electrical characteristics section. electrical characteristics (v in =17v, ta=25c, unless otherwise specifed) symbol description test condition min. typ. max. unit input v indc input dc supply voltage 8.5 v clamp v i in input operation current v indc 17v, r t =410k w gdr pin foating 0.6 1 ma i inst startup input current v indc <15v, r t =410k w 15 30 a v clamp v in clamp voltage i in =10ma 22.4 25 27.6 v internal regulator v dd internally regulated voltage v indc =12v~26v 4.5 5 5.5 v v dd, line line regulation of v dd v indc =12v~26 v, i dd =0ma 0 100 mv v dd, load load regulation of v dd v indc =17v, i dd =0ma~3ma 0 100 mv v uvlo(h) v indc under voltage lockout high threshold v indc rising for ht7l491 15 16 17 v v indc rising for ht7l491-1 7.5 8.0 8.5 v v uvlo(l) v indc under voltage lockout low threshold v indc falling for ht7l491 9 10 11 v v indc falling for ht7l491-1 6.7 7.2 7.7 v v en(l) input low voltage for pdm pin v indc =12v~26v 0.8 v v en(h) input high voltage for pdm pin v indc =12v~26v 2.0 v r en pdm pin pull-low resistor 50 100 150 k w v cs(th) current sense trip threshold voltage 0.24 0.248 0.255 v
rev. 1.20 4 march 12, 2013 ht7l4091 function al description the ht7l4091 is a universal ac/dc constant current led driver designed for peak current mode control. the d evice p rovides b oth l ed l inear a nd pw m dimming c urrent funct ions. t he hi gh i nput vol tage from a rectified 85v to 260v ac power is clamped to under 25v by an external circuit and an internal zener diode. the device also contai ns an input under - voltage-lockout (uvlo) circuit. when the voltage supplied on the vin pin exceeds the uvlo high threshold, the gate driver is enabled. if the input voltage falls below the uvlo low threshold, the gate driver is turned off. led current control the ht7l4091 device is a constant of f-time peak current mode controller . w ith reference to the application circuit, the led peak current is programmed by an external current sense resistor (r cs ) connected betwe en the cs and the ground pins. the cs p in i s c onnected t o a n on-inverting t erminal o f an internal comparator of which an internal 250mv reference is tied to the inverting terminal. the led peak current through the r cs resistor will generate a voltage which is applied on the comparator non- inverting terminal and compare with the internal 250mv reference voltage. if the voltage on the cs pin is less than the internal reference voltage 250mv , the led gate driving circuitry will be turned on. while the voltage on the cs pin is lar ger than the internal reference v oltage, t he l ed g ate d riving c ircuitry will be turned of f for a constant t off time. after the t off t ime, t he g ate d riving c ircuitry wi ll b e t urn o n if t he v oltage o n t he c s p in i s l ess t han t he i nternal reference voltage. good line regulation is a feature of constant of f-time operation and the led current is independent of the input voltage. since the inductor current ripple is dependent on the led string voltage, the led string voltage variation will result in led current variation. this is typically not a problem since the led voltage variation for a given load is fairly small. r cs can be calculated using the following equation: led peak cs iripple)/( . i . r ? + == 211 250 250 where ipeak is the maximum led current, ripple is the peak to peak led current, and i led is the average l ed c urrent. r ipple c an b e c ontrolled b y the inductor. 0 l vt iripple i out off ripple led == refer to induc tor design for t he inductor calculation. refer to programmable of f t ime for t off calculation. symbol description test condition min. typ. max. unit t delay delay from cs trip to gdr v cs =v cs_th +50mv 110 ns v ld linear dimming pin voltage range 0 v cs_th v t blank blanking interval 200 300 400 ns t off off time r t =410k w 14.7 16.4 18.1 v v ol gate output low level v indc =17v, io=-20ma 0.3 v v oh gate output high level v indc =17v, io=20ma 12 v t rise gate output rise time c gate =500pf 120 ns t fall gate output fall time c gate =500pf 50 ns t otp thermal shutdown temperature 140 7 otp thermal shutdown temperature hysteresis 25 i jitter switch frequency jitter ratio 4 % t jp jitter period f sw = 60khz 4 ms v cs-short short circuit protection voltage 0.45 0.5 0.55 v note 3: specifications are production tested at ta=room temperature. specifications over the -40c to 85c operating temperature range are assured by design, characterization and correlation with statistical quality controls (sqc).
rev. 1.20 5 march 12, 2013 ht7l4091 programmable off time the de vice op erates i n a c onstant of f-time m ode. a resistor connected between the r t pin and the ground pin generates a constant current source which is used to char ge an inter nal capacitor and determine the of f- time. increasing the resistance reduces the amplitude of t he c urrent sour ce a nd i ncreases t he of f-time. t he relationship b etween t he r esistor r t a nd t he o ff-time is given by the following formula: t off = c t r t c t =36pf~44pf, c t _ typ =40pf. for a gi ven t off a nd dut y c ycle, t he swi tching frequency (f s ) can be decided. the duty cycle is determined by the input and output voltages. current sense the current sens e input is connected to the non- inverting inputs of two comparators. the inverting terminal of one c omparator i s t ied t o a n i nternal 250mv reference whereas the other comparator inverting terminal is connected to the ld pin. the outputs of both thes e comparators are fed into an or g ate a nd t he o utput o f t he or g ate i s f ed i nto the reset pin of a fip-fop. if a fip-fop reset event is triggered by the or gate output a signal occurs where the external mosfet gate driving circuitry will be turned of f. therefore, the comparator which has the lower voltage at the inverting terminal determines when the gate driving output is turned off. leading-edge blanking each time the power mosfet is switched on, a turn-on transient spike will occur on the cs pin. t o avoid premature termination of the switching pulse, a t blank lead ing-edge blank time is generated during the mosfet switch turn-on to prevent false triggering of the current sense comparator . during this blanking period, t he c urrent-limit c omparator i s di sabled a nd the gate driving circuitry will not be switched off. in certain rare situations, the internal blanking time might not be long enough to filter out the turn-on spike. in such situations, it will be necessary to add an external rc flter between the external sense resistor (r cs ) and the cs pin. frequency jitter function the device also includes a frequency jitter function. the frequency has a variation range of +4% to -4% within four milliseconds. the frequency jitter function helps reduce power supply line emi emissions with minimum line flters. input supply current the input supply current is determined by the input operati ng current and the current drawn by the external mo sfet gate driver . this means that the input suppl y c urrent de pends upon t he swi tching frequency and the external mosfet gate charge. i insp = i in + q gate f s in addition, where i insp is the input supply current taken from the vin pin, f s is the switching frequency q gate is the gate char ge of the external mosfet and i in is the input operation current. the application circuit should provide enough i insp to ensure the application can work properly start-up current and auxiliary power source the po wer c onsumption of t he ht 7l4091 i s on e of the major ef ficiency losses if i insp drops from the rectified ac source whose voltage is much higher than the volta ge use d by the device . for ef ficiency improvements, a s mall start-up current from the rectifed ac source is used to start up the ht7l4091 and i insp can be provided from the auxiliary power source, for example: auxiliary winding. the start-up current should take into consideration the c in (v in capacitor) char ge current and the current consumption of t he ht 7l4091 du ring st art-up (i inst ). the c in char ge current shall consider how fast (t start-up ) the application is required to start operation. the start-up current can be calculated using the follow equation: upstart huvlo in inst upstart t vc ii ? ? += )( the current from auxiliary power source should be: i aux =i insp -i start-up the s tart-up current allow s a s tart-up res istor w ith a high res istance and a low -power rating. the s tart-up resistor (r inst ) is used to supply the start-up power for the device from the rectifed ac source. r inst can be calculated using the following equation: upstart huvlo ac inst i vv r ? ? ? = )( min, 2
rev. 1.20 6 march 12, 2013 ht7l4091 linear dimming the l inear di mming pi n i s use d t o c ontrol t he l ed current. the vdd pin voltage can be connected to the ld pin to obtain a voltage corresponding to the desired voltage across r cs . the ld pin can adjust the current level to reduce the illumination intensity of the leds. t o adjust the external ld pin voltage from 0mv t o 250m v c an a djust t he l ed c urrent duri ng operation. t o use the internal 250mv as the reference voltage, the ld pin can be connected to vdd. pwm dimming an external enable input named pdm is provided and can be utilized for pwm dimming of the led string. when the external pwm signal is zero, the gate driving circuitry is turned of f while the gate driving circuits are turned on when the pwm signal is high. led open and short circuit protection there wi ll be no a bnormal be havior i f t he l eds are open circuit. while some leds are shorted, the output voltage w ill be adjus ted automatically for the condition. enhanced short circuit protection when most leds are shorted in the application circuit, the current regulation may lose control resulting i n t he c urrent i ncreasing t o a n e xtremely high leve l. when the current is more than twice of the set ipeak, resultin g from externally shorted leds, the device will shut down gate driving operations. the operation state is shown in the accom panying fgure. w hen t he circuit is operating normally, v cs can be l imited t o v cs-th , whi le som e l eds a re short ed, the led current is still limited and the output voltage is adjusted to meet the current requirement. if the circuit encounters a serious short, the voltage increase of (current) in t blank would be lar ger than the decrease in t off , v cs will exceed v cs-th and reach v cs-short . the ht7l4091 will then shut down the gate driver until uvlo resets the ht7l4091. t blank v cs-short normal slight short serious short shut down v cs-th v cs t off cs vin gndrt vdd ld pdm c in r lim d 1 l 1 r cs gdr c vdd c lim
rev. 1.20 7 march 12, 2013 ht7l4091 t charge t discharge t vin 8.333ms 1 120hz ? v the waveform of input voltage in the c1 charge period: ms f t ac cp 333.8 2 1 = = ? ? ? ? ? ? ? ? ? ? ? ? ? = ? 90 )1(sin 1 2 1 arg in cp ech v v t t , where % dcripple in v v v ? = ? t discharge =t cp C t charge ms ms ms t edich 2232.6 90 %)301(sin 1 2 333.8 333.8 1 arg = ? ? ? ? ? ? ? ? ? = ? application description this section shows how to design a buck circuit led application us ing a s imple example. f or other application conditions, such as high ef ficiency solutions, refer to the ht7l4091 application notes for more details. for example: ac input voltage: v ac_typ = 110vrms; v ac_min = 95vrms; v ac_max = 125vrms; f ac = 60hz target working condition: f pwm > 40khz output voltage: led string led voltage = 8(3~3.3) = 24v~26.4v, typical 25.2v average output led current: i led = 400ma (shfwhghiflhqf re fer to the typical application circuit. input bulk capacitor C c1 the input bulk capacitor determines the ripple amplitude of input voltage after rectifcation. a lar ge capacitance generates a smaller input voltage ripple amplitude. the first design criterion to meet is that the maximum led string voltage should be less than 80% of the minimum ac input voltage (v min,ac ). note that 80% is a rough estimate here. here the lar ge ripple amplitude has a wide frequency variation which leads to increase in circuit power losses. assume that the input voltage dc ripple (v dcripple %) is equal to 30% and then calculate the c1 value. vv v v dcripple ac_ 4.262.75 8.0%)301(952 8.0%) 1( 2 min >= ? = ?? (maximum output voltage) above f ormula m eans 3 0% i nput v oltage r ipple i s approved that exceed output voltage. finally, a useful rule can fnd the valley voltage of the input voltage. u sing the f gure below , it is neces sary to calcula te the char ge time and dischar ge time of the input bulk capacitor.
rev. 1.20 8 march 12, 2013 ht7l4091 then, the minimu m capacitor value can be calculated as: ( ( ) ) ( ) ( ) f ms mav vv tivn c dc ac edisch led led 9.15 7.09529529.0 2232.6)4003.382( 2 ) 2( 1 2 2 2 _min 2 _min arg _max = ? ? ? ? ? ? ? = ? ? ? ? ? ? ? choose c1=22 f considering 20% capacitance variation, the worst case l ower v alue o f t he c apacitance i s 1 7.6 f, wh ich is much lar ger than 14.3 f. it can be calculated that the i nput dc ri pple i s 24.5 % wh en t he i nput buc k capacitor is 17.6 f. therefore, if the real capacitor value is less than the calculated value, the voltage ripple will exceed the m aximum ra nge of 30% whi ch i s t he spe cified assumption in the calculation. switching frequency and duty cycle frequency interference should be taken into account to minimise interference with other electrical appliances. here set the minim um switching frequency to a value of 4 0khz f or sa fety. i f e mi su ppression i s g ood, t he switching frequency can be decreas ed to 30kh z to obtain better effciency. since the ht7l4091 operates in constant off time, the switching frequency would be changed by the input and output voltage. the slowest switching frequency occurs when the duty cycle is at a maximum value. the maximum duty cycle can be calculated as, ( ) ( ) 2731.0 %5.241952 3.183.3 1 2 _min 1, _max min_ max_ max = ? + = ?? ? + ? == ripple ac df led dc o v v vvn v v d turn-off time s k f d t pwm off 173.18 40 2731.01 1 min_ max = ? = ? = off-time resistor C r t a resistor connect ed to the r t pin determines the of f- time which has a variation range from -10% to +10%. since the working frequency has a minimum tar get, the c t is considered to calculated the r t : ? = ? = k pf s rrct t tt off 03.413 44 173.18 choose 390k w and 13k w for r t are used the off time is: t off_typ = c t_typ r t = 40p 403k = 16.1 s t off_max = c t_max r t = 44p 403k = 17.7 s t off_min = c t_max r t = 36p 403k = 14.5 s the actual minimum frequency can be calculated as: t d k f off pwm 07.41 7.17 2731.01 1 max_ max min_ = ? = ? = f pwm_typ@vac_min = 45.2khz, f pwm_max@vac_min =50.1khz inductor design the r ipple c urrent i s se lected t o b e 30 % of t he nominal l ed c urrent. if t he l ed a verage c urrent iled is 400ma, the led string v oltage = n v led, max = 8 3.3v w here v led, max is the led maximum forward voltage, then the inductor can be calculated by the following formula. mh ma s ripple i vn t l led led off 894.3 3.0400 3.387.17 max_ = = = choose l=3.8 mh
rev. 1.20 9 march 12, 2013 ht7l4091 current sense resistor C r cs this current fows through the exte rnal sense resistor r cs and produces a ramp voltage on the cs pin. the comparators a re c onstantly c omparing t he c s p in voltage wi th bot h t he vol tage on t he l d pi n a nd t he internal 250mv reference voltage. once the blanking time has elapsed , the output of these comparators can then reset the fip fop. when one output of these two comparators switches high, the flip flop is reset and the gate driv e output switches low . the gate driv e output stays low until the sr flip flop is set by the oscillator. in a ssuming a 30% ripple in the inductor , the current sense resistor r cs can be obtained using the following formula: ? = + = ? + == 543.0 400)3.05.01( 25.0 211 250 250 ma iripple)/( . i . r ledavg peak cs choose rcs = 0.54 w input supply current assume that the input current drawn by the internal circuit from the vin pin is the sum of the current with a value of 1.0ma and the current drawn by the gate driver of the external mosfet (which in turn depends upon the switching frequency and the gate charge of the external f et). a ssume that the gate charge q gate is equal to 12nc. i insp = i in + q gate f pwm = 1ma + 12nc 50khz = 1.6ma in addition, where i insp is the input current taken from t he vin pi n, f pwm i s t he swi tching fre quency, q gate is the gate char ge of the external fet and i in is t he c urrent t aken by t he i nternal c ircuit. f pwm i s considered about the minimum input voltage and c t has a minimum value. input limit resistor (r in ) in this design, v ac_min = 95vrms, v uvlo(h)_max = 17v ? = ?? = ? ?? ? = k ma i v v v % r insp huvlo dcripple ac in 1.48 6.1 17%)301(952 ) 1( 2 max_)( min_ choose rin=60k w the input limit resistor consider the high input voltage from the rectifed clamp voltage of the internal zener diode and operating current. t wo 30 k w /1w resistors are used for rin. output capacitor C c o the capacitor, c o , flters the current through the leds thus l imiting t he pe ak c urrent of t he l ed st ring. increasing the inductor ripple current corresponds to dec reasing t he i nductor val ue a nd i nductor si ze. in order to reduce the inductor value and size and obtain a smaller led current ripple, the addition of a capacitor c o is a good way to do this. usually , a several f output capacitor is added in practical application circuits. adding c o connected across the led strings can reduce t he l ed c urrent ri pple a nd whi le i ncreasing the inductor current ripple variation can decrease the inductor value and size. to assume induct or current ripple is 80%, a smaller inductor value could be calculated. mh ma s ripple i vnt l led led off 460.1 8.0400 3.387.17 max _ = = = choose l=1.4mh and c o =1 f the actual values of c o and r cs may need to be adjusted to reduce the current ripple and obtain the target average led current. a 1 f capacitor and an r cs as shown in the above calculation are a good start point to obtain an acceptable result. since it takes some ef fort, it can reduce the inductor size/cost signifcantly.
rev. 1.20 10 march 12, 2013 ht7l4091 typical performance characteristics there are many dif ferent factors to influence efficiency of the application, such as the output power, worki ng fre quency, powe r suppl y c ircuit of the ht7l4091 and so on. the following are some measured results. effciency vs. power supply circuit C working frequency there are several dif ferent power supply circuits for the device. reference to the application circuit for s ome examples . the dif ferent circuits provide different advantages, such as high ef ficiency or low cost. follow are some ef ficiency compare for dif ferent power supply circuits. the condition is v ac= 85v~260v, f pwm 50khz (working frequency), output=52v0.2a=10.4w. decreasing f pwm or increasing the output power can enhance the effciency. efficiency compare in different application circuits (freq,min=50khz) 78 80 82 84 86 88 90 92 80 130 180 230 280 vac (v) efficiency (%) auxiliary circuit typical circuit bjt circuit the following is an example to enhance the effciency by reducing the f pwm (working frequency) to 30khz. efficiency compare with different frequency in two application circuits 81 83 85 87 89 91 93 80 130 180 230 280 vac (v) efficiency (%) auxiliary circuit 50khz bjt circuit 50khz auxiliary circuit 30khz bjt circuit 30khz efficiency for resistor only power and single input voltage the re sults of t hese c urves a re t hat e ach vo ltage corresponds to each input limit resistor . theseresults show ho w go od t he a pplication i s de signed fo r a narrow v oltage r ange u sing a r esistor t o p ower t he device. the led string means how many leds are in one string. 16s means there are 16 leds in one string. the output (led) power is kept at 10w. input voltage vs. efficiency 65 70 75 80 85 90 95 80 130 180 230 280 vac(v) efficiency(%) 16s led 14s led 12s led 10s led 8s led led string vs. efficiency 65 70 75 80 85 90 95 6 8 10 12 14 16 18 led string efficiency(%) 260vac 85vac 110vac 170vac 220vac input voltage vs. led current 150 200 250 300 350 400 450 80 130 180 230 280 vac(v) led current(ma) 16s led 14s led 12s led 10s led 8s led led string vs. led current 150 200 250 300 350 400 450 6 8 10 12 14 16 18 led string led current(ma) 260vac 85vac 110vac 170vac 220vac
rev. 1.20 11 march 12, 2013 ht7l4091 efficiency using resistor only power and 85~265 v ac input these r esult c urves u se t he sa me i nput l imit r esistor with dif ferent voltages. these results show the performance only us ing a res istor to pow er up the device for a full range voltage input. for improved effciency with a full range voltage input, refer to the following application circuit. input voltage vs. efficiency 60 65 70 75 80 85 90 95 80 130 180 230 280 vac(v) efficiency(%) 10s led 8s led 12s led 16s led 14s led led string vs. efficiency 60 65 70 75 80 85 90 95 6 8 10 12 14 16 18 led string efficiency(%) 260vac 85vac 170vac 110vac 220vac input voltage vs. led current 160 210 260 310 360 410 460 80 130 180 230 280 vac(v) led current(ma) 16s led 14s led 12s led 10s led 8s led led string vs. led current 160 210 260 310 360 410 460 6 8 10 12 14 16 18 led string led current(ma) 260vac 85vac 170vac 110va 220vac
rev. 1.20 12 march 12, 2013 ht7l4091 typical application circuit l d1 mosfet v led c filter c o g dr cs vin gnd rt ld vdd p dm r t c7 rcs r in ac emi lc lc ca1 ca2 c1 c in 0.1uf 400v 1uf/50v 0.1uf 22uf 400v c c rc essential components used optional components unused optional components zin c t 5pf this typical appli cation circuit uses a fundamental buck converter circuit. adding a co capacitor can reduce the led current ripple or reduce the inductor size while adding the rc and cc components can reduce spikes on the cs pin. if frequency jittering is considered to reduce emi an optional 5pf ct may be used to stabilise the effect. other application circuit no input bulk capacitor circuit l d1 mosfet v led c filter co g dr cs v in gnd rt ld v dd p dm c7 rcs r in ac emi lc lc ca1 ca2 0.1uf 0.1uf 400v c c r c essential components used optional components unused optional components ra rb c in 1uf/50v r t c t 5pf the application circuit is a low cost implementation which can improve the pf used within the signal input voltage range. the auxiliary winding application circuit can be chosen when used for a universal input voltage. if frequency jittering is considered to reduce emi ef fects, an optional 5pf capacitor may be added for stabilisation purposes. refer to the application notes for more details. for more details refer to the application note.
rev. 1.20 13 march 12, 2013 ht7l4091 high effciency circuit tr d1 rs mosfet g dr cs gnd rt ld v dd p dm c7 rg r sb dg rc cc ra da v in r in ac emi lc lc ca1 ca2 v led c filter c1 0.1uf 400v 22uf 400v essential components used optional components unused optional components c in 1uf/50v zin r t c t 5pf the application circuit uses the auxiliary inductor to supply the device power to obtain better effciency. if frequency jittering is used to reduce emi interference ef fects, an optional 5pf capacitor may be used for stabilisation purposes. for more details, refer to the application note for auxiliary inductor applications. for more details refert to the application note. bjt power supply application circuit the application circuit uses a bjt to supply the device power to obtain better effciency. zin c in r in bjt c filter g dr cs v in gnd rt ld v dd p dm c7 ac emi lc lc ca1 ca2 c1 0.1uf 400v 1uf 50v 0.1uf l d1 v led c o mosfet r cs c c r c r t c t 5pf 22uf 400v if frequency jittering is considered to reduce emi an optional 5pf ct may be used to stabilise the effect. for more details refer to the application note.
rev. 1.20 14 march 12, 2013 ht7l4091 bill of materials ac input voltage: v ac_typ =110vrms; v ac_min =95vrms; v ac_max =115vrms, f pwm 40khz output voltage: led string voltage =24~26.4v average output led current: i led = 400ma r+l+emi circuit (8s20p) components quantity value package part number r t 1 390k w + 13k w smd 0805 r cs 1 r300(0.3 w )+r240(0.24 w ) smd 1206 c 1 1 22 f/ 200v capxon radial fk series c flter 1 0.1 f/ 200v radi al r in 1 30k w /1w x 2 axial-0.6 c in 1 1 f / 50v smd 0805 led 160 3~3.3v/30ma everlight p-lcc-2 l2c-b4556 ac2cb2 mosfet 1 2a/600v niko-sem dpak p0260ad c 7 1 0.1 f smd 0805 d bridge 1 1a/400v df-s df04s-t d 1 1 2a/600v smb stth2r06u u 1 1 ht7l4091 nsop8 holtek l 1 3.8mh coilcraft 335d cm6676-al
rev. 1.20 15 march 12, 2013 ht7l4091 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 information. additional supplementary informati on with regard to packaging is liste d below . click on the relevant section to be transferred to the relevant website page. ? further package information (include outline dimensions, product t ape and reel specifcations) ? packing meterials information ? carton information ? pb free products ? green packages products
rev. 1.20 16 march 12, 2013 ht7l4091 8-pin sop (150mil) outline dimensions ? ms-012 symbol dimensions in inch min. nom. max. a 0.228 D 0.244 b 0.150 D 0.157 c 0.012 D 0.020 c 0.188 D 0.197 d D D 0.069 e D 0.050 D f 0.004 D 0.010 g 0.016 D 0.050 h 0.007 D 0.010 0 D 8 symbol dimensions in mm min. nom. max. a 5.79 D 6.20 b 3.81 D 3.99 c 0.30 D 0.51 c 4.78 D 5.00 d D D 1.75 e D 1.27 D f 0.10 D 0.25 g 0.41 D 1.27 h 0.18 D 0.25 0 D 8
rev. 1.20 17 march 12, 2013 ht7l4091 copyright ? 2013 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 specifications 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 .

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