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universal step-down pwm control for high brightness led lighting control HT7L4091 revision: v1.00 date: ??? i? ??? ? 011 ???i? ??? ? 011 www.datasheet.co.kr datasheet pdf - http://www..net/
rev. 1.00 ? ???i? ??? ? 011 rev. 1.00 3 ???i? ??? ? 011 HT7L4091 universal step-down pwm control for high brightness led lighting control table of contents eates latons eneal eston n ssnent n eston bsolte a atns eoene eatn anes lo aa letal caatests nton al eston led cu??ent cont?o? ................................................................................................................. ? p?og?ammab? e off time ........................................................................................................... ? cu??ent sense .......................................................................................................................... 9 leading-edge b?anking ............................................................................................................ 9 f?equency jitte? function ......................................................................................................... 9 in?ut su???y cu??ent ................................................................................................................ 9 sta?t-u? cu??ent and ?uxi?ia?y powe? sou?ce ........................................................................ 10 linea? dimming ...................................................................................................................... 10 pwm dimming ....................................................................................................................... 10 led o?en and sho?t ci?cuit p?otection ................................................................................. 10 enhanced sho?t ci?cuit p?otection ......................................................................................... 11 ????ication desc?i?tion .............................................................................................. 1? in?ut bu?k ca?acito? C c1 ...................................................................................................... 1? switching f?equency and duty cyc?e .................................................................................... 13 tu ? n-off time .......................................................................................................................... 13 off-time resisto ? C r t ........................................................................................................... 14 inducto? design ...................................................................................................................... 14 cu??ent sense resisto? C r cs ............................................................................................... 14 in?ut su???y cu??ent ............................................................................................................. 15 in?ut limit resisto? (r in ) ........................................................................................................ 15 out?ut ca?acito? C c o ........................................................................................................... 15 ty?ica? pe?fo?mance cha?acte?istics ........................................................................ 16 effciency vs. power supply circuit C working frequency .................................................... 16 effciency for resistor only power and single input voltage ................................................. 17 effciency using resistor only power and 85~265 v ?c in?ut ................................................. 1? ty?ica? ????ication ci?cuit ......................................................................................... 19 othe? ????ication ci?cuit ............................................................................................ ?0 no in?ut bu?k ca?acito? ci?cuit ............................................................................................. ?0 high effciency circuit ............................................................................................................ ?0 bjt powe ? su???y ????ication ci?cuit .................................................................................... ?1 www.datasheet.co.kr datasheet pdf - http://www..net/
rev. 1.00 ? ???i? ??? ? 011 rev. 1.00 3 ???i? ??? ? 011 HT7L4091 universal step-down pwm control for high brightness led lighting control package information ................................................................................................... 23 ?-? in sop (150mi?) out?ine dimensions ................................................................................ ?3 ree? dimensions .................................................................................................................... ?4 ca??ie? ta? e dimensions ........................................................................................................ ?5 www.datasheet.co.kr datasheet pdf - http://www..net/
rev. 1.00 4 ???i? ??? ? 011 rev. 1.00 5 ???i? ??? ? 011 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 voltage lockout function - 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 high 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 operating currents provides flexible power requirements for high efficiency or low cost applications. the switch frequency off-time can 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 in the device is a pwm dimming input which can accept an external control signal with 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 jitter function which helps to reduce emi power supply emissions. from damage should the leds be short circuited. . the device requires a minimum number of external standard compo nents and is available in an 8-pin nsop package for small area pcb applications. www.datasheet.co.kr datasheet pdf - http://www..net/
rev. 1.00 4 ???i? ??? ? 011 rev. 1.00 5 ???i? ??? ? 011 HT7L4091 universal step-down pwm control for high brightness led lighting control 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 in?ut vo?tage ?in cs i led st?ing cu??ent sense in?ut gnd powe? g?ound gdr o gate d?ive? fo? the exte?na? mosfet pdm i pwm dimming ?in ??so functions as enab?e in?ut ?in. vdd o positive powe? su???y 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 linea? dimming ?in set the current sense threshold as long as the voltage on this pin is less than 250mv (ty?.). rt i osci??ato? cont?o? ?in ? ?esisto? is connected between the rt and the gnd ? ins to set the off-time. absolute maximum ratings output current peak ...................................................................................................................... 1a storage temperature range ...................................................................................... -65c +150c junction temperature range ..................................................................................... -40c +150c cs, p dm , ld ,rt, to gnd ................................................................................. -0.3v to (v dd +0.3v) power dissipation at ta25 c .................................................................................................. 0.6w thermal resistance, sop-8 conditions beyond those listed in the specifcation is not implied and prolonged exposure to extreme www.datasheet.co.kr datasheet pdf - http://www..net/
rev. 1.00 6 ???i? ??? ? 011 rev. 1.00 7 ???i? ??? ? 011 HT7L4091 universal step-down pwm control for high brightness led lighting control recommended operating ranges input supply voltage ................................................................................... uvlo(h)+0.1v ~ v clamp operating temperature range ..................................................................................... -40c ~ +85c 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 impedance power source greater than the vclamp voltage specifed in the electrical characteristics section. 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 www.datasheet.co.kr datasheet pdf - http://www..net/
rev. 1.00 6 ???i? ??? ? 011 rev. 1.00 7 ???i? ??? ? 011 HT7L4091 universal step-down pwm control for high brightness led lighting control electrical characteristics (v in =17v, ta=25c, unless otherwise specifed) symbol description test condition min. typ. max. unit i nput v indc in?ut dc su???y vo?tage 11 v c?am? v i in in?ut o?e?ation cu??ent v indc 17v, r t = 410k gdr ?in foating 0.6 1 m? i inst sta?tu? in?ut cu??ent v indc < 15v, r t = 410k 15 30 a v c?am? v in clamp voltage i in =10m? ??.4 ? 5 ?7.6 v i nternal r egulator v dd inte?na??y ?egu?ated vo?tage v indc =12v~2 6 v 4.5 5 5.5 v v dd? ?ine line regulation of v dd v indc =12v~2 6 v, i dd = 0m? 0 100 mv v dd? ?oad load regulation of v dd v indc =17v, i dd = 0ma ~ 3m? 0 100 mv v uvlo (h) v indc unde? vo?tage ?ockout high th?esho?d v indc ?ising 15 16 17 v v uvlo (l) v indc unde? vo?tage ?ockout ?ow th?esho?d v indc fa??ing 9 10 11 v v en (l) in?ut ?ow vo?tage fo? pdm ?in v indc =12v~2 6 v 0.? v v en (h) in?ut high vo?tage fo? pdm ?in v indc =12v~2 6 v ?.0 v r en pdm ?in pu??-?ow ?esisto? 50 100 150 k v cs (th) cu??ent sense t?i? th?esho?d vo?tage 0.?4 0.?4? 0.?55 v t de?ay de?ay f?om cs t?i? to gdr v cs =v cs _ th + 50mv 110 ns v ld linea? dimming ?in vo?tage ?ange 0 v cs _ th v t b?ank b?anking inte?va? ?00 300 400 ns t off off time r t =410 k 14.7 16.4 1 ?.1 s v ol g? te out?ut low leve? v indc = 17v, io = -?0m? 0.3 v v oh g? te out?ut high leve? v indc = 17v, io = ?0m? 1? v t ?ise gate out?ut ?ise time c g? te = 500?f 1?0 ns t fa?? gate out?ut fa?? time c g? te = 500?f 50 ns t otp the?ma? shutdown tem?e?atu?e 140 ?t otp the?ma? shutdown tem?e?atu?e hyste?esis ?5 ?f jitte? switch f?equency jitte? ?atio 4 % t jp jitte? pe?iod f sw = 60khz 4 ms v cs-sho?t 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 o?e? ating tem?e?atu?e ? ange a?e assu? ed by design? cha?acte? ization and co??e? ation with statistica? qua?ity cont?o?s (sqc). www.datasheet.co.kr datasheet pdf - http://www..net/
rev. 1.00 ? ???i? ??? ? 011 rev. 1.00 9 ???i? ??? ? 011 HT7L4091 universal step-down pwm control for high brightness led lighting control function al description the HT7L4091 is a universal ac/dc constant current led driver designed for peak current mode control. the device provides both led linear and pwm dimming current functions. the high input voltage from a rectifed 85v to 260v ac power is clamped to under 25v by an external circuit and an internal zener diode. the device also contains 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 off-time peak current mode controller. with reference to the application circuit, the led peak current is programmed by an external current sense resistor (r cs ) connected between the cs and the ground pins. the cs pin is connected to a non-inverting terminal of 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 larger than the internal reference voltage, the led gate driving circuitry will be turned off for a constant t off time. after the t off time, the gate driving circuitry will be turn on if the voltage on the cs pin is less than the internal reference voltage. good line regulation is a feature of constant off-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: ( ) = = + ? cs ?eak led 0.?5 0.?5 r 1 i 1 ri???e i ? where ipeak is the maximum led current, ripple is the peak to peak led current, and i led is the average led current. ripple can be controlled by the inductor. off out led ripple tv i ripple=i l = refer to inductor design for the inductor calculation. refer to programmable off time for t off calculation. programmable off time the device operates in a constant off-time mode. a resistor connected between the rt pin and the ground pin generates a constant current source which is used to charge an internal capacitor and determine the off-time. increasing the resistance reduces the amplitude of the current source and increases the off-time. the relationship between the resistor r t and the off-time is given by the following formula: t off = c t r t c t =36pf~44pf, c t _ typ =40pf. for a given toff and duty cycle, the switching frequency (f s ) can be decided. the duty cycle is determined by the input and output voltages. www.datasheet.co.kr datasheet pdf - http://www..net/
rev. 1.00 ? ???i? ??? ? 011 rev. 1.00 9 ???i? ??? ? 011 HT7L4091 universal step-down pwm control for high brightness led lighting control current sense the current sense input is connected to the non-inverting inputs of two comparators. the inverting terminal of one comparator is tied to an internal 250mv reference whereas the other comparator inverting terminal is connected to the ld pin. the outputs of both these comparators are fed into an or gate and the output of the or gate is fed into 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 off. 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. to avoid premature termination of the switching pulse, a t blank leading-edge blank time is generated during the mosfet switch turn-on to prevent false triggering of the current sense comparator. during this blanking period, the current-limit comparator is disabled and the gate driving circuitry will not be switched off. in certain rare situations, the internal blanking time might not be long enough to flter 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. i nput supply current the input supply current is determined by the input operati ng current and the current drawn by the external mosfet gate driver. this means that the input supply current depends upon the switching frequency and the external mosfet gate charge. i insp = i in + q gate f s , where i insp is the input supply current taken from the vin pin, f s is the switching frequency q gate is the gate charge 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 www.datasheet.co.kr datasheet pdf - http://www..net/
rev. 1.00 10 ???i? ??? ? 011 rev. 1.00 11 ???i? ??? ? 011 HT7L4091 universal step-down pwm control for high brightness led lighting control start-up current and auxiliary power source the power consumption of the HT7L4091 is one of the major effciency losses if i insp drops from the rectified ac source whose voltage is much higher than the voltage used by the device. for effciency improvements, a small 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) charge current and the current consumption of the HT7L4091 during start-up (i inst ). the c in charge 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: in uvlo( h ) start up inst start up cv ii t ? ? = + the current from auxiliary power source should be: aux insp start up ii i ? = ? the start-up current allows a start-up resistor with a high resistance and a low-power rating. the start-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: min,ac uvlo(h) inst start-up 2v v r i ?? = linear dimming the linear dimming pin is used to control the led 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. to adjust the external ld pin voltage from 0mv to 250mv can adjust the led current during operation. to 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 off while the gate driving circuits are turned on when the pwm signal is high. led open and short circuit protection there will be no abnormal behavior if the leds are open circuit. while some leds are shorted, the output voltage will be adjusted automatically for the condition. www.datasheet.co.kr datasheet pdf - http://www..net/
rev. 1.00 10 ???i? ??? ? 011 rev. 1.00 11 ???i? ??? ? 011 HT7L4091 universal step-down pwm control for high brightness led lighting control enhanced short circuit protection when most leds are shorted in the application circuit, the current regulation may lose control resulting in the current increasing to an extremely high level. when the current is more than twice of the set ipeak, resulting from externally shorted leds, the device will shut down gate driving operations. the operation state is shown in the accompanying fgure. when the circuit is operating normally, v cs can be limited to v cs-th , while some leds are shorted, 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 larger 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 b?ank t off v cs -th v cs - sho?t normal slight short serious short shut down v cs g dr cs vin gnd rt v dd ld p dm r lim d 1 l 1 r cs c lim c vdd c in www.datasheet.co.kr datasheet pdf - http://www..net/
rev. 1.00 1? ???i? ??? ? 011 rev. 1.00 13 ???i? ??? ? 011 HT7L4091 universal step-down pwm control for high brightness led lighting control application description this section shows how to design a buck circuit led application using a simple example. for other application conditions, such as high effciency solutions, refer to the HT7L4091 application notes for more details. for example: ac input voltage: v ?c_ty? =110vrms; v ?c_min =95vrms; v ?c_max =125vrms; f ?c =60hz ta ?get wo?king condition: f pwm > 40khz output voltage: led string led voltage =8(3~3.3)=24v~26.4v, typical 25.2 ? ve?age out?ut led cu??ent: i led = 400m? expected effciency: =90% re fer to the typical application circuit. input bulk capacitor C c1 the input bulk capacitor determines the ripple amplitude of input voltage after rectification. a large capacitance generates a smaller input voltage ripple amplitude. the frst 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 large 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. ? v ?c_min (1-v dc?i???e %)0.?= ? 95(1-30%) 0.8=75.2v>26.4v(maximum output voltage) above formula means 30% input voltage ripple is approved that exceed output voltage. finally, a useful rule can fnd the valley voltage of the input voltage. using the fgure below, it is necessary to calculate the charge time and discharge time of the input bulk capacitor. t cha?ge t discha?ge t v in ?.333ms 1 1 ? 0hz v the waveform of input voltage in the c1 charge period: cp ac 1 t 8.333ms 2f u u 1 cp in cha?ge v sin (1 ) t v t= 1 ? 90 ? whe?e in v v d = v dc?i???e % www.datasheet.co.kr datasheet pdf - http://www..net/
rev. 1.00 1? ???i? ??? ? 011 rev. 1.00 13 ???i? ??? ? 011 HT7L4091 universal step-down pwm control for high brightness led lighting control t discha?ge =tcpC t cha?ge t discha?ge =?.333ms C 1 ?.333ms sin (1 30%) 1 ? 90 ? ? ?? ? ?? ?? = 6.??3?ms then, the minimum capacitor value can be calculated as: ( ) ( ) ledmax led discha?ge 1 ? ? ?cmin dcmin (2 n v i ) t c 2v v ?? ? ? ?? ?? = ( ) ( ) ?? (2 16 3.3v 200ma) 6.2232ms 0.9 ? ?5 ? ?5 0.7 ?? ? ?? ?? = 14.3uf choose c1=??uf rqlghlqjfdsdflwdqfhydldwlrqwkhzrwfdhorzhydoxhriwkhfdsdflwdqfhlx) zklfklpxfkodjhwkdqx)?wfdqehfdofxodwhgwkdwwkhlqsxw'lssohlzkhqwkh input buck capacitor is 17.6uf. therefore, if the real capacitor value is less than the calculated value, the voltage ripple will exceed wkhpdlppudqjhrizklfklvwkhvshflhgdvvpswlrqlqwkhfdofodwlrq switching frequency and duty cycle frequency interference should be taken into account to minimise interference with other electrical appliances. here set the minimum switching frequency to a value of 40khz for safety. if emi vssuhvvlrqlvjrrgwkhvzlwfklqjiuhthqffdqehghfuhdvhgwrn+wrrewdlqehwwhuhiflhqf 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, ?+ = = ? ? o_ max led_ max f?d1 max dc_ min ?c_ min ?i???e v nv v d v 2 v (1 v ) = + 3.3 ? 1.3 ? 95 (1-?4.5%) =0.?731 turn-off time ? = max off pwm_ min 1d t f = ? 1 0.?731 40k =1?.173us www.datasheet.co.kr datasheet pdf - http://www..net/
rev. 1.00 14 ???i? ??? ? 011 rev. 1.00 15 ???i? ??? ? 011 HT7L4091 universal step-down pwm control for high brightness led lighting control off-time resistor C r t a resistor connected to the rt pin determines the off-time which has a variation range from -10% to +10%. since the working frequency has a minimum target, the c t is considered to calculated the r t : t off = c t r t r t 1?.173us 44?f = 413.03k? choose 390k and 13k for r t a?e used the off time is: t off_ty ? = c t_ty? r t = 40? x 403k = 16.1us t off_max = c t_max r t = 44? x 403k = 17.7us t off_min = c t_max r t = 36? x 403k = 14.5us the actua? minimum f?equency can be ca?cu?ated as: max pwm_ min off_ max 1d 1 0.?731 f 41.17k t 17.7u f pwm_typ@vac_min = 44.3khz? f pwm_max@vac_min =50.1 khz inductor design the ripple current is selected to be 30% of the nominal led current. if the led average current iled is 400ma, the led string voltage = n v led, max = 8 3.3v where v led, max is the led maximum forward voltage, then the inductor can be calculated by the following formula. off led?max led t nv l i ri???e uu u = 3 . 0 400 15 . 3 8 7 . 17 ? ? ? ma us = 3.717mh choose l=3.? mh current sense resistor C r cs this current fows through the external sense resistor r cs and produces a ramp voltage on the cs pin. the comparators are constantly comparing the cs pin voltage with both the voltage on the ld pin and the 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 fip fop is reset and the gate driv e output switches low. the gate driv e output stays low until the sr fip fop 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: cs ?eak ledavg 0.?5 0.?5 r 1 i 1 ri???e i ? u = 0.?5 (1 0.5 0.3) 400m? u u = 0.543? choose r cs = 0.54? www.datasheet.co.kr datasheet pdf - http://www..net/
rev. 1.00 14 ???i? ??? ? 011 rev. 1.00 15 ???i? ??? ? 011 HT7L4091 universal step-down pwm control for high brightness led lighting control 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 fet). assume that the gate charge q gate is equal to 12nc. =+? insp in gate pwm i iq f = 1m? + 1?nc 50khz = 1.6m? , where i insp is the input current taken from the vin pin, f pwm is the switching frequency, q gate is the gate charge of the external fet and i in is the current taken by the internal circuit. f pwm is 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 ? ?? ? = ac_ min dcripple% uvlo(h)_max in insp 2 v (1 v ) v r i = ? 95 (1 30%) 17 1.6m? ? ? =62.4k choose rin=60k the input limit resistor consider the high input voltage from the rectified clamp voltage of the lqwhuqdo=hqhuglrghdqgrshudwlqjfuuhqw7zr.:uhvlvwruvduhvhgiru5lq output capacitor C c o the capacitor, c o owhuvwkhfuuhqwwkurjkwkh/(vwkvolplwlqjwkhshdnfuuhqwriwkh/( string. increasing the inductor ripple current corresponds to decreasing the inductor value and inductor size. in order to reduce the inductor value and size and obtain a smaller led current ripple, the addition of a capacitor c o lvdjrrgzdwrgrwklvvdoodvhhudo)rwswfdsdflwrulv added in practical application circuits. adding c o connected across the led strings can reduce the led current ripple and while increasing the inductor current ripple variation can decrease the inductor value and size. 7rdvvphlqgfwrufuuhqwulssohlvdvpdoohulqgfwrudohfrogehfdofodwhg = off led _ max led t nv l i ri???e = 17.7us ? 3.15 400m? 0.? =1.393mh choose l=1.4mh and c o =1uf 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 1uf 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 effort, it can reduce the inductor vlhfrvwvljqlfdqwo www.datasheet.co.kr datasheet pdf - http://www..net/
rev. 1.00 16 ???i? ??? ? 011 rev. 1.00 17 ???i? ??? ? 011 HT7L4091 universal step-down pwm control for high brightness led lighting control typical performance characteristics there are many different factors to infuence effciency of the application, such as the output power, working frequency, power supply circuit of the HT7L4091 and so on. the following are some measured results. effciency vs. power supply circuit C working frequency there are several different power supply circuits for the device. reference to the application circuit for some examples. the different circuits provide different advantages, such as high effciency or low cost. follow are some efficiency compare for different power supply circuits. the condition is vac=85vac~260vac, f pwm >= 50 khz (HT7L4091 working frequency), output=52vx0.2a=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 (HT7L4091 working frequency) to >=30 khz. 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 www.datasheet.co.kr datasheet pdf - http://www..net/
rev. 1.00 16 ???i? ??? ? 011 rev. 1.00 17 ???i? ??? ? 011 HT7L4091 universal step-down pwm control for high brightness led lighting control effciency for resistor only power and single input voltage the results of these curves are that each voltage corresponds to each input limit resistor. theseresults show how good the application is designed for a narrow voltage range using a resistor to power the 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 www.datasheet.co.kr datasheet pdf - http://www..net/
rev. 1.00 1? ???i? ??? ? 011 rev. 1.00 19 ???i? ??? ? 011 HT7L4091 universal step-down pwm control for high brightness led lighting control 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 effciency using resistor only power and 85~265 v ac input these result curves use the same input limit resistor with different voltages. these results show the performance only using a resistor to power 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 www.datasheet.co.kr datasheet pdf - http://www..net/
rev. 1.00 1? ???i? ??? ? 011 rev. 1.00 19 ???i? ??? ? 011 HT7L4091 universal step-down pwm control for high brightness led lighting control 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 typical application circuit l d1 mosfet v led c fi?te? c o g dr cs v in gnd rt ld v dd p dm r t c7 rcs r in ?c emi lc lc ca1 ca? c1 c in 0.1uf 400v 1uf/50v 0.1uf ??uf 400v c c r c essentia? com?onents used optional components unused optional components zin c t 5?f this typical application 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. www.datasheet.co.kr datasheet pdf - http://www..net/
rev. 1.00 ?0 ???i? ??? ? 011 rev. 1.00 ?1 ???i? ??? ? 011 HT7L4091 universal step-down pwm control for high brightness led lighting control other application circuit no input bulk capacitor circuit l d1 mosfet v led c fi?te? c o g dr cs v in gnd rt ld v dd p dm c7 rcs r in ?c emi lc lc ca1 ca? 0.1uf 0.1uf 400v c c r c essentia? com?onents used optional components unused optional components ra rb c in 1uf/50v r t c t 5?f 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 effects, 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. high effciency circuit t? d1 rs mosfet g dr cs gnd rt ld v dd p dm c7 rg rsb dg rc cc ra da v in r in ?c emi lc lc ca1 ca? v led c fi?te? c1 0.1uf 400v ??uf 400v essentia? com?onents used optional components unused optional components c in 1uf/50v zin r t c t 5?f the application circuit uses the auxiliary inductor to supply the device power to obtain better hiflhqf if frequency jittering is used to reduce emi interference effects, 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. www.datasheet.co.kr datasheet pdf - http://www..net/
rev. 1.00 ?0 ???i? ??? ? 011 rev. 1.00 ?1 ???i? ??? ? 011 HT7L4091 universal step-down pwm control for high brightness led lighting control 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 fi?te? g dr cs v in gnd rt ld v dd p dm c7 ?c emi lc lc ca1 ca? c1 0.1uf 400v 1uf 50v 0.1uf l d1 v led c o mosfet rcs c c r c r t c t 5?f ??uf 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. www.datasheet.co.kr datasheet pdf - http://www..net/
rev. 1.00 ?? ???i? ??? ? 011 rev. 1.00 ?3 ???i? ??? ? 011 HT7L4091 universal step-down pwm control for high brightness led lighting control bill of materials ac input voltage: v ?c_ty? =110vrms; v ?c_min =95vrms; v ?c_max =115vrms, f pwm 40khz output voltage: led string voltage =24~26.4v ? ve?age out?ut led cu??ent: i led = 400m? r+l+emi circuit (8s20p) components quantity value package part number r t 1 390k+ 13k smd 0?05 r cs 1 r300(0.3)+r240(0.24) smd 1?06 c 1 1 22uf/ 200v capxon radia? fk se?ies c flter 1 0.1uf/ 200v radi a? r in 1 30k/1w x 2 ?xi?l-0.6 c in 1 1uf / 50v smd 0?05 led 160 3~3.3v/30ma eve??ight p-lcc-? l?c-b4556?c- c-b4556?c- -b4556?c- ?c - ? cb ? mosfet 1 2a/600v niko-sem dp ?k p0?60?d c 7 1 0.1uf smd 0?05 d b?idge 1 1a/400v df-s df04s-t d 1 1 2a/600v smb stth2r06u u 1 1 HT7L4091 nsop? holtek l 1 3.?mh coi?c?aft 335d cm6676-?l www.datasheet.co.kr datasheet pdf - http://www..net/
rev. 1.00 ?? ???i? ??? ? 011 rev. 1.00 ?3 ???i? ??? ? 011 HT7L4091 universal step-down pwm control for high brightness led lighting control package information 8-pin sop (150mil) outline dimensions ms-012 symbol dimensions in inch min. nom. max. ? 0.??? D 0.?44 b 0.150 D 0.157 c 0.01? D 0.0?0 c 0.1?? 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. ? 5.79 D 6.?0 b 3.?1 D 3.99 c 0.30 D 0.51 c 4.7? D 5.00 d D D 1.75 e D 1.?7 D f 0.10 D 0.?5 g 0.41 D 1.?7 h 0.1? D 0.?5 0 D 8 www.datasheet.co.kr datasheet pdf - http://www..net/
rev. 1.00 ?4 ???i? ??? ? 011 rev. 1.00 ?5 ???i? ??? ? 011 HT7L4091 universal step-down pwm control for high brightness led lighting control reel dimensions sop 8n symbol description dimensions in mm ? ree? oute? diamete? 330.01.0 b ree? inne? diamete? 100.01.5 c s?ind?e ho?e diamete? 13.0 +0.5/-0.? d key s?it width ?.00.5 t1 s?ace between f?ange 1?.? +0.3/-0.? t? ree? thickness 1?.?0.? www.datasheet.co.kr datasheet pdf - http://www..net/
rev. 1.00 ?4 ???i? ??? ? 011 rev. 1.00 ?5 ???i? ??? ? 011 HT7L4091 universal step-down pwm control for high brightness led lighting control carrier tape dimensions

sop 8n symbol description dimensions in mm w ca??ie? ta? e width 1?.0 +0.3/-0.1 p cavity pitch ?.00.1 e pe?fo?ation position 1.750.1 f cavity to pe?fo?ation (width di?ection) 5.50.1 d pe?fo?ation diamete? 1.550.1 d1 cavity ho?e diamete? 1.50 +0.?5/-0.00 p0 pe?fo?ation pitch 4.00.1 p1 cavity to pe?fo?ation (length di?ection) ?.00.1 ?0 cavity length 6.40.1 b0 cavity width 5.?0.1 k0 cavity de?th ?.10.1 t ca??ie? ta?e thickness 0.300.05 c cove? ta? e width 9.30.1 www.datasheet.co.kr datasheet pdf - http://www..net/
rev. 1.00 ?6 ???i? ??? ? 011 rev. 1.00 pb ???i? ??? ? 011 HT7L4091 universal step-down pwm control for high brightness led lighting control holtek semiconductor inc. (headquarters) no.3? c?eation rd. ii? science pa?k? hsinchu? taiwan te ?: ??6-3-563-1999 fax: ?? 6-3-563-11?9 htt? ://www.ho?tek.com.tw holtek semiconductor inc. (taipei sales offce) 4f-?? no. 3-?? yuanqu st.? nankang softwa?e pa?k? tai? ei 115? taiwan te ?: ??6-?-?655-7070 fax: ??6-?-?655-7373 fax: ??6-?-?655-73?3 (inte?nationa? sa?es hot?ine) holtek semiconductor inc. (shenzhen sales offce) 5f, unit a, productivity building, no.5 gaoxin m 2nd road, nanshan district, shenzhen, china 518057 te ?: ?6-755-?616-990?? ?6-755-?616-930? fax: ?6-755-?616-97?? holtek semiconductor (usa), inc. (north america sales offce) 46729 fremont blvd., fremont, ca 94538, usa te ?: 1-510-?5?-9??0 fax: 1-510-?5?-9??5 htt? ://www.ho?tek.com co?y?ight ? 2011 by holtek semiconductor inc. the info?mation a??ea? ing in this data sheet is be? ieved to be accu? ate at the time of ?ub? ication. howeve ?? ho? tek assumes no ?es?onsibi? ity a?ising f ? om the use of the s? ecifications desc ? ibed. the a??? ications mentioned he ? ein a? e used so?e? y fo? the ?u?? ose of i??ust? ation and ho? tek makes no wa?? anty o? representation that such applications will be suitable without further modifcation, nor recommends the use of its ?? oducts fo? a??? ication that may ??esent a ? isk to human ? ife due to ma?function o? othe?wise. ho?tek's ??oducts a?e not autho? ized fo? use as c?itica? com?onents in ?ife su??o?t devices o? systems. ho?tek ?ese?ves the right to alter its products without prior notifcation. for the most up-to-date information, please visit our web site at htt? ://www.ho?tek.com.tw . www.datasheet.co.kr datasheet pdf - http://www..net/

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