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1/26 www.rohm.com 2010.03 - rev.a ? 2010 rohm co., ltd. all rights reserved. led drivers for lcd backlights white backlight led driver for medium to large lcd panels (switching regulator type) BD6581GU description BD6581GU is white led driver ic with pwm step-up dc/dc converter that can boost ma x 42.5v and current driver that can drive max 25ma. the wide and precision brightne ss can be controlled by external pwm pulse. BD6581GU has very accurate current drivers, and it has few current errors between each strings. so, it will be helpful to reduce brightness spots on the lcd. small package type is suited for saving space. features 1) high efficiency pwm step-up dc/dc converter (fsw=1mhz), max efficiency 93% 2) high accuracy & good matching ( 1.5%) current drivers 6ch 3) drive up to 12 in series, 6 strings in parallel =72 white leds ( white led vf=3.5vmax) 4) wide input voltage range (2.7v ~ 22v) 5) rich safety functions ? over-voltage protection (ovp) ? over current limit ? external sbd open detect ? thermal shutdown 6) small & thin package (vcsp85h2) 2.6 2.6 0.85mm absolute maximum ratings all middle size lcd equipments backlight of notebook pc, portable dvd player, car navigation systems, etc. parameter symbol ratings unit condition maximum applied voltage 1 vmax1 7 v test, vreg, sensp, sensn, sw, rstb, pwmpow, pwmdrv, failsel, iseth, isetl maximum applied voltage 2 vmax2 25 v led1, led2, led3, led4, led5, led6, vbat maximum applied voltage 3 vmax3 50.5 v vdet power dissipation 1 pd1 1100 mw *1 operating temperature range topr -30 ~ +85 - storage temperature range tstg -55 ~ +150 - (*1) this value is the measurement val ue that was mounted on the pcb by rohm. temperature deleting: 8.8mw/ from ta>25 recommended operating range (ta=-30 ~ +85 ) parameter symbol limits unit condition min. typ. max. power supply voltage vbat 2.7 12.0 22.0 v no.10040eat13
technical note 2/26 www.rohm.com 2010.03 - rev.a ? 2010 rohm co., ltd. all rights reserved. BD6581GU electrical characteristic(unl ess otherwise specified, vbat=12v, rstb=2.5v, ta = +25 ) parameter symbol limits unit condition min. typ. max. [failsel,pwmdrv terminal] en threshold voltage (low) vthl 0 - 0.2 v en threshold voltage (high) 1 vthh1 1.4 - 5.0 v vbat>5.0v en threshold voltage (high) 2 vthh2 1.4 - vbat v vbat<5.0v en terminal input current iin - 8.3 14.0 a input=2.5v [pwmpow terminal] low input voltage range pwml 0 - 0.2 v high input voltage range1 pwmh1 1.4 - 5.0 v vbat>5.0v high input voltage range2 pwmh2 1.4 - vbat v vbat<5.0v pwm pull down resistor pwmr 300 500 700 k ? [rstb terminal] low input voltage range rstbl 0 - 0.2 v high input voltage range1 rstbh1 2.25 2.5 5.0 v vbat>5.0v high input voltage range2 rstbh2 2.25 2.5 vbat v vbat<5.0v current consumption irstb - 89 134 a rstb=2.5v, led1-6=3v [regulator] vreg voltage vreg 4.0 5.0 6.0 v no load under voltage lock out uvlo 2.05 2.25 2.65 v [switching regulator] quiescent current 1 iq1 - 0.6 3.4 a rstb=0v, vbat=12v quiescent current 2 iq2 - 4.6 10 a rstb=0v, vbat=22v current consumption idd - 3.4 5.1 ma vdet=0v,iseth=24k ? led control voltage vled 0.4 0.5 0.6 v over current limit voltage ocp 70 100 130 mv *1 sbd open protect sop - - 0.1 v detect voltage of vdet pin switching frequency fsw 0.8 1.0 1.2 mhz duty cycle limit duty 92.5 95.0 99.0 % led1-6=0.3v over voltage limit ovl 43.0 44.7 46.4 v led1-6=0.3v [current driver] led maximum current ilmax - - 25 ma led current accuracy ilaccu - - 3 % iled=16ma led current matching ilmat - - 1.5 % each led current/average (led1- 6) iled=16ma iset voltage iset 0.5 0.6 0.7 v led current limiter ilocp 35 60 90 ma current limit value at iset resistance 4.7k ? setting led1, 2, 3, 4, 5, 6=0.5v led terminal over voltage protect ledovp 10.0 11.5 13.0 v rstb=pwmdrv=2.5v (*1) this parameter is tested with dc measurement.
technical note 3/26 www.rohm.com 2010.03 - rev.a ? 2010 rohm co., ltd. all rights reserved. BD6581GU 2.2 2.22 2.24 2.26 2.28 2.3 -60 25 110 ta [ o c] vbat [v] reference data 0 2 4 6 8 10 12 14 16 18 20 0 10203040506070809010 0 duty (%) led current (ma) fig.1 current consumption vs vbat fig.2 quiescent current vs vbat fig.3 oscillation frequency vs vbat fig.4 uvlo vs temperature fig.6 efficiency vs pwmdrv-hi duty iseth=24k ? , pwm=200hz 0 2 4 6 8 10 12 14 16 18 20 0 10203040506070809010 0 duty (%) led current (ma) 0.0 0.1 0.2 0.3 0.4 0.5 0.6 0.7 0.8 0.9 1.0 00.511.522.533.544.55 duty (%) led current(ma) fig.7 led current vs pwmdrv-hi duty pwm = 200hz fig.8 led current vs pwmdrv-hi duty ( expansion) pwm = 200hz 12v 16v 6v 12v 16v 6v 0 2 4 6 8 10 12 14 16 18 20 0 10203040506070809010 0 duty (%) led current(ma) 0.0 0.1 0.2 0.3 0.4 0.5 0.6 0.7 0.8 0.9 1.0 00.511.522.533.544.55 duty (%) led current(ma) fig.10 led current vs pwmpow-hi duty tpwm = 200hz fig.11 led current vs pwmpow-hi duty ( expansion) pwm = 200hz fig.9 led current vs pwmdrv-hi duty pwm = 200hz, 1khz,10khz fig.12 led current vs pwmpow-hi duty pwm = 200hz, 1khz,10khz 0 2 4 6 8 10 12 14 16 18 20 0 102030405060708090100 duty (%) led current(ma) 200hz 1khz 10khz 200hz 1khz 10khz 12v 16v 6v 12v 16v 6v 0 1 2 3 4 5 6 7 8 2 4 6 8 10 12 14 16 18 20 22 vbat[v] ist[ a] 25 -60 125 0.8 0.85 0.9 0.95 1 1.05 1.1 1.15 1.2 2 7 12 17 22 vbat [v] frequency [mhz] -60 125 o c 25 0 0.5 1 1.5 2 2.5 3 3.5 4 4.5 0 2 4 6 8 1012141618202224 vbat [v] iin [ma] -30 25 85 ta=-50,+25,+125 ta=-50,+25,+125 ta=-50,+25,+125 ta=-50,+25,+125 fig.5 efficiency vs pwmpow-hi duty iseth=24k ? , pwm=200hz 125 60% 65% 70% 75% 80% 85% 90% 95% 100% 0 102030405060708090100 duty [%] efficiency [] 6v 12v 16v 60% 65% 70% 75% 80% 85% 90% 95% 100% 0 102030405060708090100 duty [%] efficiency [] 6v 12v 16v
technical note 4/26 www.rohm.com 2010.03 - rev.a ? 2010 rohm co., ltd. all rights reserved. BD6581GU fig.21 line transient (22v to 10v) fig.18 vout response power control pwm (pwmpow) fig.22 vout@ovp (led open) vout icc led curren t fig.13 led current matching vs pwmdrv-hi duty pwm = 200hz fig.14 led current matching vs pwmdrv-hi duty (expansion) pwm = 200hz fig.16 led current matching vs pwmpow-hi duty pwm = 200hz fig.17 led current matching vs pwmpow-hi duty (expansion) pwm = 200hz fig.15 vout response driver control pwm (pwmdrv) pwmdrv vout 10ma/div 350mv -3.0 -2.0 -1.0 0.0 1.0 2.0 3.0 0% 20% 40% 60% 80% 100% pwm hi duty (%) current matching (%) -3.0 -2.0 -1.0 0.0 1.0 2.0 3.0 0% 2% 4% 6% 8% 10% pwm hi duty (%) current matching (%) max matching = max led current/average current min matching = min led current/average current max matching = max led current/average current min matching = min led current/average current pwmpo w vout led current 180mv -3.0 -2.0 -1.0 0.0 1.0 2.0 3.0 0% 20% 40% 60% 80% 100% pwm hi duty (%) current matching (%) -3.0 -2.0 -1.0 0.0 1.0 2.0 3.0 0% 2% 4% 6% 8% 10% pwm hi duty (%) current matching (%) 10ma/div max matching = max led current/average current min matching = min led current/average current max matching = max led current/average current min matching = min led current/average current fig.19 led current vs temperature pwmdrv=h, iseth=30k ? (16ma setting) fig.20 line transient (10v to 22v) 15.70 15.75 15.80 15.85 15.90 15.95 16.00 16.05 16.10 16.15 16.20 16.25 16.30 -60 -40 -20 0 20 40 60 80 100 120 temp [oc] ledcurrent [ma] 2.7v 5v 7v 12v 22v [ ] vbat vout led current 400 s no peak 14ms vbat vout led curren t no peak
technical note 5/26 www.rohm.com 2010.03 - rev.a ? 2010 rohm co., ltd. all rights reserved. BD6581GU package outline bd6581 numbe r lot no.
technical note 6/26 www.rohm.com 2010.03 - rev.a ? 2010 rohm co., ltd. all rights reserved. BD6581GU block diagram, i/o equivalent circuit diagram pin assignment table pin name in/out pin number function terminal equivalent circuit diagram a1 vdet in detect input for sbd open and ovp c a2 n.c. - no connect pin f a3 sw out switching tr drive terminal g a4 sensp in + side current sense terminal g a5 sensn in - side current sense terminal a b1 n.c. - no connect pin f b3 test in test input (pull down 100k ? to gnd) g b4 iseth in resistor connection for ,led current setting at pwmdrv=h a b5 gnd - gnd b c1 vbat in battery input c c2 pwmpow in pwm input pin for power on/off e c3 vreg out regulator output / internal power-supply d c4 isetl in resistor connection for ,led current setting at pwmdrv=l a c5 pwmdrv in pwm input pin for power on/off only driver e d1 rstb in reset pin l :reset h :reset cancel e d2 gnd - gnd b d3 failsel in latch selectable pin of protect function e d4 gnd - gnd b d5 led1 in current sink for led1 c e1 led6 in current sink for led6 c e2 led5 in current sink for led5 c e3 led4 in current sink for led4 c e4 led3 in current sink for led3 c e5 led2 in current sink for led2 c fig.23 block diagram gnd vbat vreg pin a vbat pin b gnd pin c gnd vbat pin d gnd vbat pin e 5.5v clump pin f gnd vbat pin g vreg fig.24 i/o equivalent circuit diagram current sence s q r - + - + over voltage protect sbd open protect vin detector reg internal power suplly vdet sw uvlo rstb 300k ? current driver + - - - led1 led2 led3 erramp + + - osc control sence 100k ? pwmcomp test pwmpow sensp sensn led4 - 1m ? 100k ? led terminal over voltage protect 500k ? vbat vreg failsel pwmdrv - - led5 led6 + - pwmdrv=h on iset l resistor driver pwmdrv=l on iseth isetl iset h resistor driver 300k ? tsd 300k ? gnd gnd gnd gnd led terminal detect
technical note 7/26 www.rohm.com 2010.03 - rev.a ? 2010 rohm co., ltd. all rights reserved. BD6581GU application example fig.25 10 series x 6parallel hi current 20ma setting fig.26 10 series x 4parallel hi current 20ma setting current driver pwm application current driver pwm application * please select the capacitor which the little bias fluctuation. fig.27 10 series x 6parallel led current 20ma setting fig.28 non-used inside reg or operating under 5v application power control pwm application * please select the capacitor which the little bias fluctuation. terminal processing test pin = connect to gnd n.c. = nothing specified in particular. open is recommended. vreg = when ic is driving from the outside of 2. 7~5.5v, short vbat and vreg, and put the voltage to vreg failsel, pwmdrv = connect to gnd in case of fixing at l level. connect to vreg of ic or the power supply of more than 1.4v in case of fixing at h level . led1-6 = when each led driver are not used, connect to gnd of ic gnd = each gnd is connecting inside ic, but, connect to gnd of all board rstb = rstb is used as a power supply of internal circuit. so, you mustn?t input rstb voltage with pull up resistor of several k ? . and, please care about the relation between vbat and rstb enough. 10 f batter y vdet sw led1 led2 led3 4.7 h 10led x 6parallel sensp sensn led4 each 20ma 100m ? rtr020n05 2.2 f * rstb pwmpow pwmdrv power on/off 200hz pwm vbat led5 led6 failsel gnd 24k ? test gnd iseth vreg 1 f isetl gnd gnd 10 f batter y vdet sw led1 led2 led3 4.7 h 10led x 4aprallel sensp sensn led4 each 20ma 150m ? rtr020n05 2.2 f * rstb pwmpow pwmdrv power on/off 200hz pwm vbat led5 led6 fai lsel gnd 24k ? test gnd iseth vreg 1 f isetl gnd gnd 10 f batter y vdet sw led1 led2 led3 4.7 h 10led x 6parallel sensp sensn led4 each 20ma 100m ? rtr020n05 2.2 f * rstb pwmpow pwmdrv power on/off 200hz pwm vbat led5 led6 fai lsel gnd 24k ? test gnd iseth vreg 1 f isetl gnd gnd 10 f batter y vdet sw led1 led2 led3 4.7 h 10led x 6parallel sensp sensn led4 each 20ma 100m ? rtr020n05 2.2 f * rstb pwmpow pwmdrv power on/off 200hz pwm vbat led5 led6 failsel vreg 1 f 2.7v to 5.5v gnd 24k ? test gnd iseth isetl gnd gnd
technical note 8/26 www.rohm.com 2010.03 - rev.a ? 2010 rohm co., ltd. all rights reserved. BD6581GU description of functions 1) pwm current mode dc/dc converter while BD6581GU is power on, the lowest voltage of led1, 2, 3, 4, 5, 6 is detected, pwm dut y is decided to be 0.5v and output voltage is kept invariably. as for the inputs of the pwm comparator as the feature of the pwm cu rrent mode, one is overlapped with error components from the error amplifier, and the other is overlapped with a current sense signal that controls the inductor current into slope waveform to prevent s ub harmonic oscillation. this out put controls external nch tr via the rs latch. in the period where external nch tr gate is on, energy is accumula ted in the external inductor, and in the period where external nch tr gate is off, energy is transferred to the output capacitor via external sbd. BD6581GU has many safety functions, and their dete ction signals stop switching operation at once. 2) soft start BD6581GU has soft start function. the soft start function prevents large coil current. rush current at turning on is prevented by the soft start function. after rstb is changed l ? h, when pwmpow is changed l ? h, soft start becomes effective for within 1ms and soft start doesn't become effective even if pwmpow is changed l ? h after that. and, when the h section of pwmpow is within 1ms, soft start becomes invalid when pwmpow is input to h more than three times. the invalid of the soft start can be canceled by making rstb ? l. 3) failsel pin when the error condition occurs, boost operating is stopped by the protection function, and t he error condition is avoided. on that occasion, the way to stop of bo ost operating by the protection function can be selected with failsel pin. details are as shown in fig.29, 30. after power on, when the protection function is operating under about 1ms have passed, the stop state of the boost operating can be held through failsel is h, t he stop state can reset through rstb is l. and, boost operating is stopped when the protection function is operating through failsel is l, but when the protection function becomes un-detect, boost operating is started again. it never keeps holding the st op state of boost operating. object of protect function is as shown below. ? over-voltage protection ? external sbd open detect ? thermal shutdown ? led terminal over-voltage protection ? over current limit fig.29. failsel operating description fig.30. failsel=h light off control in pwm control by pwmdrv can?t use this function. when it is off over 10ms on pwm control by pwmpow usi ng this function, it may be stopped the boost operating as over current p rotection work at off on pwmpow=l. about 1ms un-operating range failsel rstb protection function normal operating off un-detection detection normal o p eratin g boost stop off normal ?l? un-detectio boost operating rstb pwmdrv pwmpow invalid output voltage coil current failsel function < when it is off on rstb> rstb pwmdrv coil current failsel function invalid valid < when it is off on pwmpow> output voltage pwmpow about 1ms un-operating range failsel rstb protection function detection boost operating normal operating off boost stop ?h? off normal operating un-detection un-detection
technical note 9/26 www.rohm.com 2010.03 - rev.a ? 2010 rohm co., ltd. all rights reserved. BD6581GU 4) external sbd open detect and over voltage protection BD6581GU has over boost protection by external sbd open and over voltage protection. it detects vdet voltage and is stopped output tr in abnormal condition. details are as shown below. ? external sbd open detect in the case of external sbd is not connec ted to ic, the coil or external tr may be destructed. therefore, at such an error as vout becoming 0.1v or below, the under detector shown in the figure wo rks, and turns off the output tr, and prevents the coil and the ic from being destructed. and the ic changes from activation into non-activa tion, and current does not flow to the coil (0ma). ? over voltage protection at such an error of output open as the output dc/dc and th e led is not connected to ic, the dc/dc will boost too much and the vdet terminal exceed the absolute maximum ratings, and may destruct the ic. therefore, when vdet becomes sensing voltage or higher, the over voltage limit works, and turns off the output tr, and the pressure up made stop. at this moment, the ic changes from activation into non-acti vation, and the output voltage goes down slowly. and, when the output voltage becomes the hyst eresis of the over voltage limit or below, the output voltage pressure up to sensing voltage once again and unless the application error is recovered, this operation is repeated. 5) thermal shut down BD6581GU has thermal shut down function. the thermal shut down works at 175 ? c or higher, and the ic changes from activation into non-activation. because non-activation is different from rstb=l, it doesn?t? be reset insi de ic. moreover, even if thermal shut down function works, soft start, failsel, selection the number of led lines of the current driver and starting current setting at pwmdrv=l related rstb are hold. 6) over current limit over current flows the current detection resistor that is connected to switch ing transistor source and between gnd, sensp pin voltage turns more than detection voltage, over current protection is operating and it is prevented from flowing more than detection current by reducing on duty of switching tr without stopping boost. as over current detector of BD6581GU is detected peak current, current more than over current setting value does not flow. and, over current value can decide freely by changing over current detection voltage. detection resistor =over current detecti on voltage / over current setting value typ value of over current detection voltage is 100mv, mi n = 70mv and max = 130mv and after the current value which was necessary for the normal operation was decided, detection re sistor is derived by using min value of over current detection value. for example, detection resistor when necessary current value was set at 1a is given as shown below. detection resistor =70mv / 1a = 70m ? max current dispersion of this detection resistor value is max current = 130mv / 70m ? = 1.86a as over current detector of BD6581GU is detected the peak current, it have to esti mate peak current to flow to the coil by operating condition. in case of, supply voltage of coil = vin inductance value of coil = l switching frequency = fsw min=0.8mhz, typ=1mhz, max=1.2mhz output voltage = vout total led current = iout average current of coil = iave peak current of coil = ipeak ef ficiency = eff (please set up having margin, it refers to data on p.3.) on time of switching transistor = ton ipeak = (vin / l) x (1 / fsw) x (1-(vin / vout)) iave=(vout x iout / vin) / eff ton=(iave x (1-vin/vout) x (1/fsw) x (l/vin) x 2) 1/2 each current is calculated. as peak current varies according to whether there is the direct current superposed, the next is decided. (1-vin/vout) x (1/fsw) < ton peak current = ipeak /2 + iave (1-vin/vout) x (1/fsw) > ton peak current = ipeak (example 1) in case of, vin=6.5v, l=4.7h, fsw=1m hz, vout=39v, iout=80ma, efficiency=85% ipeak = (6.5v / 4.7h) x (1 / 1mhz) x (1-(6.5v / 39v)) =1.08a iave = (39v x 80ma / 6.0v) / 85% = 0.61a ton = (0.61a x (1-6.0v / 39v) x (1 / 1mhz) x ( 4.7h /6.0v) x 2) 1/2 = 0.90s (1-vin/vout) x (1 /fsw)=0.85s < ton peak current = 1.08a/2+0.61a = 1.15a
technical note 10/26 www.rohm.com 2010.03 - rev.a ? 2010 rohm co., ltd. all rights reserved. BD6581GU (example 2) in case of, vin=12.0v, l=4.7h, fsw=1m hz, vout=39v, iout=80ma, efficiency=85% ipeak = (12.0v / 4.7h) x (1 / 1mhz) x (1-(12v / 39v)) =1.77a iave = (39v x 80ma / 12.0v) / 85% = 0.31a ton = (0.31a x (1-12 v / 39v) x (1 / 1mhz) x ( 4.7h /12 v) x 2) 1/2 = 0.41s (1-vin/vout) x (1 /fsw)=0.69s > ton peak current = 12v/4.7h x 0.41s = 1.05a *when too large current is set, output overshoot is caus ed, be careful enough because it is led to break down of the ic in case of the worst. operating of the application deficiency 1) when 1 led or 1parallel open during the operating in case of failsel=l, the led parallel which became o pen isn't lighting, but other led parallel is lighting. at that time, output boosts up to the over voltage protection voltage 44.7v so th at led terminal may be 0v or it boost to the output voltage that led terminal voltage becomes led terminal over voltage protection 11.5v or it becomes the output voltage restricted by t he over current limit. in case of failsel=h, boost stops when led becomes open and all led turns off the lights. 2) when led short-circuited in the plural in case of failsel=l, all led is turned on unless led terminal voltage is led terminal over voltage protection of more than 11.5v. when it was more than 11.5v only the line which s hort-circuited is turned on normally and led current of other lines fall or turn off the lights. in case of failsel=h, boost stops at more than 11.5v and all led turns off the lights. 3) when schottky diode came off regardless of failsel, all led isn't turned on. also, ic and a switching transistor aren't destroyed because boost operating stops by the schottky diod e coming off protected function. 4)when over current detection resistor came off regardless of failsel, all led isn't turned on. because the resistance of 100k ? is between sensp and sensn terminal, over current protection works instantly and led current can't be flow. control signal input timing in case you input control signs, such as rstb, pwmpow, and pw mdrv, in the condition that the standup of supply voltage (vbat) is not completed, be careful of the following point. input each control signal after vbat exceeds 2.7v. please do not input each control sign until vbat exceeds hi voltage of rstb, pwmpow, and pwmdrv. when you input rstb during the standup of vba t and hi voltage is inputted into pwmpow, please give the standup time to stable voltage as min.100s 2.7v of vbat. there is no timing limitation at each input signal of rstb, pwmpow and pwmdrv. if each control sign changes into a condition lower than vbat in (1) and (2), it goes via the esd custody diode by the side of vbat of each terminal. a power supply is supplied to vbat and there is a possibility of ma lfunctioning. moreover, when the entrance current to the terminal exceeds 50ma, it has possibility to damage the lsi. in order to avoid this condition, as shown in the above figure, please insert about 220ohm in a signal line, and apply current qua lification. please confirm an internal pull down resistor in the block diagr am and electrical property of p.5. vbat rstb vreg min. 100 s 2.7v dc/dc vout pwmpow pwmdrv 5v 5v figure.32 voltage with a control sign higher than vbat example corresponding to application of conditions figure.31 control signal timing ?r gnd vbat pin rin 0v 5v 220?
technical note 11/26 www.rohm.com 2010.03 - rev.a ? 2010 rohm co., ltd. all rights reserved. BD6581GU how to select the number of led lines of the current driver when the number of led lines of the curren t driver is reduced, the un-select can be set the matter that the unnecessary led1 ~ 6 terminal is connected to gnd. when it uses with 4 lines and so on, it can correspond to it by connecting 2 unnecessary lines to gnd. rstb is used as a power supply of this decision circuit. the se lect of the terminal is judged, it has no relation to the logic of pwmpow and pwmdrv and it isn't judged an unnecessary led line even if it is connected to gnd when it is judged a necessary terminal once. this information can be reset by setting rstb at 0v. start control and select led current driver BD6581GU can control the ic system by rstb, and ic can power off compulsory by setting 0.2v or below. also, it powers on pwmpow is at more than 1.4v and rstb is at more than 2.25v. when rstb=pwmpow=h, iseth current is selected at pwmdrv=h and isetl current is selected at pwmdrv=l. the starting current in pwmdrv=l sets off second time rise of pwmdrv and it becomes 0ma setting after that. after rstb sets l once, the starting current can be flowed again by changing it to h. rstb pwmpow pwmdrv ic led current 1 0 0 off off 1 1 0 on starting current decided with isetl 1 0 1 off off 1 1 1 on current decided with iseth 0 0, 1 0, 1 off off attendance point of the restriction resistance input to rstb when the restriction resistance is input to rstb, it is necessary to consider the input current of rstb. the input current of rstb changes that depending on the power-supply voltage and the temperature reference to fig.33. because the temperature characte ristic of the input current is shown in fi g.33, please choose resistance for which the voltage of the terminal can be guaranteed to 2.1v or more. and, it has the margin in the decision of resistance, and please confirm and make sure it is no problem in a real application. the decision example of restriction resistance 1. when use the current driver of 6 parallel 2.9v(to rstb power-supply) - restriction resistance value 124a(100 input current) 2.1v restriction resistance value (2.9-2.1)/124 a=6.45k ? 2. when use the current driver of 3 parallel 2.9v(to rstb power-supply) - restriction resistance value430 a(100 input current) 2.1v restriction resistance value (2.9-2.1)/430 a=1.86k ? fig .33 fig .34 rstb terminal voltage-rstb inflow current (at the time of the current driver six lines use) in addition, the selection number of parallel number of the curr ent driver is changed, the powe r-supply current of rstb will be increased.because the maximum value of t he consumption current at the rstb=2.1v is indicated in the following table 1, be careful enough when you calculate the restriction resistance. table. the use parallel number of current driver at rstb=2.1v , 100 vs. rstb input current parallel numbers used for current driver rstb input current 6 0.12ma 5 0.23ma 4 0.33ma 3 0.43ma 2 0.53ma 1 0.63ma 0 0.74ma limit resistor rstb terminal BD6581GU rstb inflow current power supply for rstb 50 100 150 200 250 2.1 2.4 2.7 3 3.3 3.6 rstb[v ] rstb input current[ua] -30 +25 +80 +100
technical note 12/26 www.rohm.com 2010.03 - rev.a ? 2010 rohm co., ltd. all rights reserved. BD6581GU start to use pwmpow terminal for the pwm control, pwm operating after rstb and pwmdrv is changing l h, input pwm to pwmpow terminal. there is no constraint in turn of rstb and pwmdrv. and, because it corresponds to pwm drive of shorter on time than soft start time (1ms), when pwmpow is input h more than three times, the soft start is in validated and it enable to correspond the high -speed drive. until rstb is set l, invalidation of the soft start isn't canceled. in case of lighting light off lighting, when it turns off the lights with pwm=l and it starts without soft start when it sets pwm modulated light again. but the peak current of the coil changes owing to discharge of output capacitor, it may flow to the over current limit value, a s follows fig.35. because soft start can be used when it turns of f the lights with rstb=l, the peak current of the coil can be suppressed, as follows fig.36 and this process of light off is recommended. fig.35 light off control of pwmpow pin at pwm control on pwm=l fig.36 light off control of pwmpow pin at pwm control on rstb=l rstb pwmdrv pwmpow output voltage current coil rstb pwmdrv pwmpow output voltage current coil
technical note 13/26 www.rohm.com 2010.03 - rev.a ? 2010 rohm co., ltd. all rights reserved. BD6581GU l h l h l h l on off on of f rstb pwmpow pwmdrv output volta g e led pin current driver o f starting current rstb pwmpow pwmdrv output voltage current coil rstb pwmpow pwmdrv output voltage current coil start to use pwmdrv terminal for the pwm control, pwm operating after rstb and pwmpow is changing l h, input pwm to pwmdrv terminal. there is no constraint in turn of rstb and pwmpow. after rstb and pwmpow is changing l h as follows fig.37, when it is not input pwm to pwmdrv pin but input l, boost of dc/dc is unstable state because current driver doesn?t pass current. the starting current is pulled from each led terminal and pressu re up operating is stabilized to escape from this state. also, the starting current can be set up by the re sistance value connected to the isetl terminal. after starting, as the starting current in pwm brightness control become useless, the starting current is set up 0ma at the second rise time of pwmdrv aut omatically as follows fig.37. in case of lighting light off lighting, when it turns off the lights with pw m=l and it starts without soft start because of soft start period was end when it sets pwm modulated light again. but the peak current of the coil changes owing to discharge of output capacitor, it may flow to the over current limit value, a s follows fig.38. because soft start can be used when it turns of f the lights with rstb=l, the peak current of the coil can be suppressed, as follows fig.39 and this process of light off is recommended. fig. 37 off timing of starting current at pwmdrv=l fig.38 light off control of pwmdrv pin at pwm control on pwm=l fig.39 light off control of pwmdrv pin at pwm control on rstb=l
technical note 14/26 www.rohm.com 2010.03 - rev.a ? 2010 rohm co., ltd. all rights reserved. BD6581GU brightness control there are two dimming method is available, first method is analog dimming that apply analog voltage to iset terminal, and second method is pwm control via digital dimming of pwmpow or pwmdrv. because each method has the different merit, please choose a suitable method for the application of use. two techniques can be used as digital dimming by the pwm cont rol one is pwm control of curr ent driver, the other is pwm control of power control. as these two characteristics are shown in the below, sele cts to pwm control process comply with application. ? efficiency emphasis in the low brightness whic h has an influence with the battery life 2) power control pwm control ? led current dispersion emphasis in the pwm brightness control 1) current driver pwm control (reference) pwm regulation process efficiency of led current 0.5ma (pwm duty=2.5%) pwm frequency 200hz limit dispersion capability of low duty current driver 70% 0.2% power control 93% 0.5% 1) current driver pwm control is controlled by provid ing pwm signal to pwmdrv, as it is shown fig.25. the current set up with iseth is chosen as the hi section of pwmdrv and the current is off as t he lo section. therefore, the average led current is increasing in proportion to duty cycl e of pwmdrv signal. this me thod that it lets internal circuit and dc/dc to work, because it becomes to switch the driver, the current tole rance is a few when the pwm brightness is adjusted, it makes it po ssible to brightness control until 50s (min1% at 200hz). and, don't use for the brightness control, because effect of iseth, isetl changeover is big under 50s on time and under 50s off time. typical pwm frequency is 100hz~10khz. when rstb sets h l, so the starting current may be effective, after rstb sets l h, it becomes pwm of the starting current and pwm of iseth setting current to pwm two times. pwmdrv led current coil current ic?s active current on off on off on off on fig.40 2) power control pwm control is controlled by providing pwm si gnal to pwmpow, as it is shown fig.27. the current setting set up with pwmdrv logic is chosen as the hi section and the current is off as the lo secti on. therefore, the average led current is increasing in proportion to duty cycle of pwmp ow signal. this method is, because ic can be power-off at off-time, the consumption current can be suppress, and the high efficiency can be available, so it makes it possible to brightness control until 50s (min1% at 2 00hz). and, don't use for the brightness control, because effect of power on/off time changeover is big under 50s on time and under 50s off time. typical pwm frequency is 100hz~1khz. also, pwm can' t control rstb and pwmpow at the same time. after rstb sets h, control pwm only pwmpow. pwmpow led current coil current ic?s active current on off on off on off on off fig.41
technical note 15/26 www.rohm.com 2010.03 - rev.a ? 2010 rohm co., ltd. all rights reserved. BD6581GU led current setting range led current can set up normal and starting setting current. led current can set up normal current by resistance value (r iseth) connecting to iseth voltage and led current can set starting current by resistance value (risetl) connecting to isetl voltage. setting of each led current is given as shown below. normal current = 20ma(24k ? /riseth) starting consta nt current = 0.6/riset l also, normal current setting range is 10ma~25ma, starti ng current setting range is off setting or 1a~100a. led current can set off setting by open setting isetl pin. led current becomes a leak current max 1a at off setting. iseth normal current setting example isetl starting current setting example riseth led current risetl led current 24k ? (e24) 20ma 6.2k ? (e24) 97a 25.5 k ? (e96) 18.8ma 10k ? (e6) 60a 27 k ? (e12) 17.8ma 47k ? (e6) 13a 28k ? (e96) 17.1ma 100 k ? (e6) 6a 30k ? (e24) 16.0ma 560 k ? (e12) 1.1a 33k ? (e6) 14.5ma connect to vreg pin 0ma the separations of the ic power supply and coil power supply this ic can work in separating the power source in both ic powe r supply and coil power supply. with this application, it can obtain that decrease of ic power consumption, and the applied voltage exceeds ic rating 22v. that application is shown in below figure 42. the higher voltage so urce is applied to the power source of coil that is connecte d from an adapter etc. next, the ic power s upply is connected with a different coil po wer supply. under the conditions for inputt ing from 2.7v to 5.5v into ic vbat, please follow the recommend des ign in figure 38. it connects vbat terminal and vreg terminal together at ic outside. when the coil power supply is applied, it is no any problem ev en though ic power supply is the state of 0v. although ic power supply is set to 0v, pull-down resistance is arranged for the power off which cuts off the leak route from coil power supply in ic inside, the leak route is cut off. and, there is no power on-off sequence of coil power su pply and ic power supply. fig.42 application at the time of power supply isolation 10 f batter y vdet sw led1 led2 led3 4.7 h 10led x 6 sensp sensn led4 20ma each 100m ? rtr020n05 2.2 f rstb pwmdrv pwmpow power on/off 200hz pwm vbat led5 led6 fai lsel vreg 1 f 2.7v to 5.5v gnd 24k ? test gnd iseth isetl gnd gnd 7v to 28v coil power supply ic power supply
technical note 16/26 www.rohm.com 2010.03 - rev.a ? 2010 rohm co., ltd. all rights reserved. BD6581GU the coil selection the dc/dc is designed by more than 4.7h. when l value sets to a lower value, it is po ssibility that the specific sub-harmonic oscillation of current mode dc / dc will be happened.please do not let l value to 3.3h or below. and, l value increases, the phase margin of dc / dc becomes to zero. please enlarge the output capacitor value when you increase l value. example) 4.7h = output capacitor 2.2f/50v 1pcs 6.8h = output capacitor 2.2f/50v 2pcs 10h = output capacitor 2.2f/50v 3pcs this value is just examples, please made sure the final judgment is under an enough evaluation. layout in order to make the most of the performance of this ic, its la yout pattern is very important. characteristics such as efficien cy and ripple and the likes change greatly with layout patterns, which please note carefully. rstb test iseth vbat gnd pwmpow vreg isetl pwmdrv gnd failsel gnd led1 led5 led4 led3 led2 led6 vdet sw sensp sensn 12345 a b c d e rese t pwm to gnd to cathode of led c ba t c in c out c reg l r sense riset to anode of each led sbd t r fig. 43 layout connect the input bypath capacitor cin(10f) near est to coil l, as shown in the upper diagram. wire the power supply line by the low resistance from cin to vbat pin. thereby, the input vo ltage ripple of the ic can be reduced. connect smoothing capacitor creg of the regulator nearest to between vreg and gnd pin, as shown in the upper diagram. connect schottky barrier diode sbd of the r egulator nearest to between coil l and switching transistor tr. and connect output capacitor cout nearest to between cin and g nd pin. thereby, the output vo ltage ripple of the ic can be reduced. connect switching transistor tr nearest to sw pin. wire co il l and switching transistor tr, current sensing resistor r sense by the low resistance. wiring to the sensp pin isn't tr side, but connect it from r sense side. over current value may become low when wiring from tr side. connect r sense of gnd side isolated to sens pin. don?t wire between r sense and snesn pin wiring from r sense pin to gnd pin. and r sense gnd line must be wired directly to gnd pin of output capacitor. it has the possibility that restricts the current drive performance by the influence of the noise when other gnd is connected to this gnd. connect led current setting resistor riset nearest to iset pin. there is possibility to oscill ate when capacity is added to iset terminal, so pay attention that capacity isn't added. and, riset of gnd side must be wired directly to gnd pin. when those pins are not connect ed directly near the chip, influence is given to the performance of BD6581GU, and may limit the current drive performance. as for the wi re to the inductor, make its resistance component small so as to reduce electric power consumption and increase the entire efficiency.
technical note 17/26 www.rohm.com 2010.03 - rev.a ? 2010 rohm co., ltd. all rights reserved. BD6581GU selection of external parts recommended external parts are as shown below. when to use other parts than these, sele ct the following equivalent parts. ? coil value manufacturer product number size dc current (ma) dcr (? ) vertical horizontal height (max) 4.7 h toko a915ay-4r7m 5.2 5.2 3.0 1870 0.045 4.7 h toko b1015as-4r7m 8.4 8.3 4.0 3300 0.038 4.7 h toko a1101as-4r7m 4.1 4.1 1.2 1400 0.115 4.7 h tdk ltf5022t-4r7n2r0 5.0 5.2 2.2 2000 0.073 4.7 h tdk vlp6810t-4r7m1r6 6.3 6.8 1.0 1600 0.167 10 h tdk vlp6810t-100m1r1 6.3 6.8 1.0 1100 0.350 ? capacitor value pressure manufacturer product number size tc cap to l vertical horizontal height [ supply voltage capacitor ] 10 f 25v murata grm31cb31e106k 3.2 1.6 1.6 0.2 b +/-10% 10 f 10v murata grm219r61a106k 2.0 1.25 0.85 0.15 x5r +/-10% 4.7 f 25v murata grm319r61e475k 3.2 1.6 0.85 0.1 x5r +/-10% 4.7 f 25v murata grm21br61e475k 2.0 1.25 1.25 0.1 x5r +/-10% [ smoothing capacitor for built-in regulator ] 1 f 10v murata grm188b10j105k 1.6 0.8 0.8 0.1 b +/-10% [ output capacitor ] 1 f 50v murata grm31mb31h105k 3.2 1.6 1.15 0.1 b +/-10% 1 f 50v murata grm21bb31h105k 2.0 1.25 1.25 0.1 b +/-10% 2.2 f 50v murata grm31cb31h225k 3.2 1.6 1.6 0.2 b +/-10% 0.33 f 50v murata grm219b31h334k 2.0 1.25 0.85 0.1 b +/-10% ? resistor value tolerance manufacturer product number size vertical horizontal height [ resistor for led current decision ] 30k ? 0.5% rohm mcr006yzpd303 0.6 0.3 0.23 [ resistor for over current decision ] 100m ? 1% rohm mcr10ezhfsr100 2.0 1.25 0.55 ?sbd pressure manufacturer product number size vertical horizontal height 60v rohm rb160m-60 3.5 1.6 0.8 ? mos fet nch pressure manufacturer product number size current ability driving voltage vertical horizontal height 45v rohm rtr020n05 2. 8 2.9 1.0 2a 2.5v 60v rohm rss065n06 6.0 5.0 1.75 6.5a 4.0v the coil is the part that is mo st influential to efficiency. select the coil wh ose direct current resist or (dcr) and current - inductance characteristic is excellent. BD6581GU is design ed for the inductance value of 4.7h. doesn?t use the inductance value less than 2.2 h. select a capacitor of ceramic type with excellent frequency and temperature characteristics. further, select capacitor to be used with sma ll direct current resistance, and pay sufficient attention to th e layout pattern shown in p.15.
technical note 18/26 www.rohm.com 2010.03 - rev.a ? 2010 rohm co., ltd. all rights reserved. BD6581GU attention point of board layout in board pattern design, the wiring of power supply line shou ld be low impedance, and put the bypass capacitor if necessary. especially the wiring impedance must be lower around the dc/dc converter. about heat loss in heat design, operate the dc/dc conv erter in the following condition. (the following temperature is a guarantee te mperature, so consider the margin.) 1. periphery temperature ta must be less than 85 o c. 2. the loss of ic must be less than dissipation pd.
technical note 19/26 www.rohm.com 2010.03 - rev.a ? 2010 rohm co., ltd. all rights reserved. BD6581GU notes for use (1) absolute ma ximum ratings an excess in the absolute maximum ratings, such as supply voltage, temperature range of operating conditions, etc., can break down devices, thus making impossible to identify break ing mode such as a short circuit or an open circuit. if any special mode exceeding the absolute maximum ratings is assu med, consideration should be given to take physical safety measures including the use of fuses, etc. (2) operating conditions these conditions represent a range within which characte ristics can be provided approximately as expected. the electrical characteristics are guaranteed under the conditions of each parameter. (3) reverse connection of power supply connector the reverse connection of power supply connector can break down ics. take protective measures against the breakdown due to the reverse connection, such as mount ing an external diode between the power supply and the ic?s power supply terminal. (4) power supply line design pcb pattern to provide low impedance for the wiring between the power supply and t he gnd lines. in this regard, for the digital block power supply and the analog block po wer supply, even though these power supplies has the same level of potential, separate the power supply pattern for the digital block from that for the analog block, thus suppressing the diffraction of digital noises to the analog block power supply resulting from impedance common to the wiring patterns. for the gnd line, give consideration to design the patterns in a similar manner. furthermore, for all power supply terminals to ics, mount a capacitor between the power s upply and the gnd terminal. at the same time, in order to use an electrolytic capacitor, thoroughly check to be sure the characteristics of the capacitor t o be used present no problem including the occurrence of capacity dropout at a low temperature, thus determining the constant. (5) gnd voltage make setting of the potential of the gnd terminal so that it will be maintained at the minimum in any operating state. furthermore, check to be sure no terminals are at a potential lower than the gnd voltage includi ng an actual electric transient . (6) short circuit between terminals and erroneous mounting in order to mount ics on a set pcb, pay thorough attention to the direction and offs et of the ics. e rroneous mounting can break down the ics. furthermore, if a short circuit occurs due to foreign matters entering between terminals or between the terminal and the power supply or t he gnd terminal, the ics can break down. (7) operation in strong electromagnetic field be noted that using ics in the strong elec tromagnetic field can malfunction them. (8) inspection with set pcb on the inspection with the set pcb, if a capacitor is connected to a low-impedanc e ic terminal, the ic can suffer stress. therefore, be sure to discharge from the set pcb by each proc ess. furthermore, in order to mount or dismount the set pcb to/from the jig for the inspection process, be sure to tu rn off the power supply and then mount the set pcb to the jig. after the completion of the inspection, be sure to turn off the power supply and then dismount it from the jig. in addition, for protection against static el ectricity, establish a ground for the assembly process and pay thorough attention to the transportation and the stor age of the set pcb. (9) input terminals in terms of the construction of ic, paras itic elements are inevitably formed in re lation to potential. the operation of the parasitic element can cause interference wi th circuit operation, thus resulting in a malfunction and then breakdown of the input terminal. therefore, pay thorough attention not to handle t he input terminals, such as to apply to the input terminals a voltage lower than the gnd respectively, so that any parasitic element will operate. furthermore, do not apply a voltage to the input terminals when no power supply voltage is applied to the ic. in addition, even if the power supply voltage is applied, apply to the input terminals a volt age lower than the power supply voltag e or within the guaranteed value of electrical characteristics. (10) ground wiring pattern if small-signal gnd and large-current gnd are provided, it will be recommended to separ ate the large-current gnd pattern from the small-signal gnd pattern and establish a si ngle ground at the reference point of the set pcb so that resistance to the wiring pattern and voltage fluctuations due to a large current will cause no fluctuations in voltages of the small-signal gnd. pay attention not to cause fluctuations in the gnd wiring pattern of external parts as well. (11) external capacitor in order to use a ceramic capacitor as the external capaci tor, determine the constant wi th consideration given to a degradation in the nominal capacitance due to dc bias and changes in the capacitance du e to temperature, etc. (12) thermal shutdown circuit (tsd) when junction temperatures become 175c (typ) or higher, the thermal shutdown circuit operates and turns a switch off. the thermal shutdown circuit, which is aimed at isolating the lsi from thermal runaway as much as possible, is not aimed at the protection or guarantee of the lsi. therefore, do not c ontinuously use the lsi with this circuit operating or use the lsi assuming its operation. (13) thermal design perform thermal design in which there are adequate margins by taking into account the permissible dissipation (pd) in actual states of use. (14) selection of coil select the low dcr inductors to decr ease power loss for dc/dc converter.
technical note 20/26 www.rohm.com 2010.03 - rev.a ? 2010 rohm co., ltd. all rights reserved. BD6581GU application example ? led current setting controlled iseth resistor. 24k ? : 20ma 30k ? : 16ma 19.6k ? : 24.5ma 33k ? : 14.5ma ? brightness control please input pwm pulse from pwmpow or pwmdrv terminal. please refer electrical characteri stic p.3 and function (p.12). 15inch panel 10 f batter y vdet sw led1 led2 led3 4.7 h 10led x 6 parallel sensp sensn led4 each 20ma 47m ? rtr020n05 2.2 f * rstb pwmpow pwmdrv power on/off 100hz~10khz pwm vbat led5 led6 failsel gnd 24k ? test gnd iseth vreg 1 f isetl gnd gnd can be set up to each 10 ~25ma fig.44 10 series 6 parallel, led current 20ma setting current driver pwm application 13~14inch panel 10 f batter y vdet sw led1 led2 led3 4.7 h 8led x 6 parallel sensp sensn led4 each 20ma 51m ? rtr020n05 2.2 f * rstb pwmpow pwmdrv power on/off 100hz~1khz pwm vbat led5 led6 failsel gnd 24k ? test gnd iseth vreg 1 f isetl gnd gnd can be set up to each 10~25ma 10 f batter y vdet sw led1 led2 led3 4.7 h 8led x 6 parallel sensp sensn led4 each 20ma 51m ? rtr020n05 2.2 f * rstb pwmpow pwmdrv power on/off 100hz~10khz pwm vbat led5 led6 failsel gnd 24k ? test gnd iseth vreg 1 f isetl gnd gnd can be set up to each 10~25ma fig.45 8 series 6 parallel, led current 20ma setting fig.46 8 series 6 parallel, led current 20ma setting power control pwm application current driver pwm application (unit : mm)
technical note 21/26 www.rohm.com 2010.03 - rev.a ? 2010 rohm co., ltd. all rights reserved. BD6581GU ? led current setting controlled iseth resistor. 24k ? : 20ma 30k ? : 16ma 19.6k ? : 24.5ma 33k ? : 14.5ma ? brightness control please input pwm pulse from pwmpow or pwmdrv terminal. please refer electrical characteri stic p.3 and function (p.12). 10~12inch panel 10 f batter y vdet sw led1 led2 led3 4.7 h 7led x 6 parallel sensp sensn led4 each 16ma 56m ? rtr020n05 2.2 f * rstb pwmpow pwmdrv power on/off 100hz~10khz pwm vbat led5 led6 failsel gnd 30k ? test gnd iseth vreg 1 f isetl gnd gnd can be set up to each 10~25ma 10 f batter y vdet sw led1 led2 led3 4.7 h 10led x4 parallel sensp sensn led4 each 20ma 56m ? rtr020n05 2.2 f * rstb pwmpow pwmdrv power on/off 100hz~10khz pwm vbat led5 led6 failsel gnd 24k ? test gnd iseth vreg 1 f isetl gnd gnd can be set up to each 10~25ma fig.47 7 series ? 6 parallel, led current 16ma setting fig.48 10 series ? 4 parallel, led current 20ma setting current driver pwm application current driver pwm application 7inch panel 10 f batter y vdet sw led1 led2 led3 4.7 h 8led x 3 parallel sensp sensn led4 each 20m a 68m ? rtr020n05 2.2 f * rstb pwmpow pwmdrv power on/off 100hz~10khz pwm vbat led5 led6 failsel gnd 24k ? test gnd iseth vreg 1 f isetl gnd gnd can be set up to each 10~25ma 10 f batter y vdet sw led1 led2 led3 4.7 h 6led x 4 parallel sensp sensn led4 each 20ma 68m ? rtr020n05 2.2 f * rstb pwmpow pwmdrv power on/off 100hz~10khz pwm vbat led5 led6 failsel gnd 24k ? test gnd iseth vreg 1 f isetl gnd gnd can be set up to each 10~25ma fig.49 8 series ? 3 parallel, led current 20ma setting fig.50 6 series ? 4 parallel, led current 20ma setting current driver pwm application current driver pwm application
technical note 22/26 www.rohm.com 2010.03 - rev.a ? 2010 rohm co., ltd. all rights reserved. BD6581GU ? led current setting controlled iseth resistor. 24k ? : 20ma 30k ? : 16ma 19.6k ? : 24.5ma 33k ? : 14.5ma ? brightness control please input pwm pulse from pwmpow or pwmdrv terminal. please refer electrical characteri stic p.3 and function (p.12). 7inch panel 10 f batter y vdet sw led1 led2 led3 4.7 h 4led x 6 parallel sensp sensn led4 each 20m a 68m ? rtr020n05 2.2 f * rstb pwmpow pwmdrv power on/off 100hz~1khz pwm vbat led5 led6 failsel gnd 24k ? test gnd iseth vreg 1 f isetl gnd gnd can be set up to each 10~25ma 10 f batter y vdet sw led1 led2 led3 4.7 h 8led x 3 parallel sensp sensn led4 each 40ma 68m ? rtr020n05 2.2 f * rstb pwmpow pwmdrv power on/off 100hz~1khz pwm vbat led5 led6 failsel gnd 24k ? test gnd iseth vreg 1 f isetl gnd gnd can be set up to each 20~50ma fig.51 4 series ? 6 parallel, led current 20ma setting fig.52 8 series ? 3 parallel, led current 40ma setting power control pwm application power control pwm application 5inch panel 10 f batter y vdet sw led1 led2 led3 4.7 h 8led x 2 parallel sensp sensn led4 each 20ma 82m ? rtr020n05 2.2 f * rstb pwmpow pwmdrv power on/off 100hz~10khz pwm vbat led5 led6 failsel gnd 24k ? test gnd iseth vreg 1 f isetl gnd gnd can be set up to each 10~25ma 10 f batter y vdet sw led1 led2 led3 4.7 h 8led x 2 parallel sensp sensn led4 each 40ma 82m ? rtr020n05 2.2 f * rstb pwmpow pwmdrv power on/off 100hz~1khz pwm vbat led5 led6 failsel gnd 24k ? test gnd iseth vreg 1 f isetl gnd gnd can be set up to each 20~50ma fig.53 8 series ? 2 parallel, led current 20ma setting fig.54 8 series ? 2 parallel, led current 40ma setting current driver pwm application power control pwm application
technical note 23/26 www.rohm.com 2010.03 - rev.a ? 2010 rohm co., ltd. all rights reserved. BD6581GU ? led current setting controlled iseth resistor. 24k ? : 20ma 30k ? : 16ma 19.6k ? : 24.5ma 33k ? : 14.5ma ? brightness control please input pwm pulse from pwmpow or pwmdrv terminal. please refer electrical characteri stic p.3 and function (p.12). 5inch panel 10 f batter y vdet sw led1 led2 led3 4.7 h 4led x 4 parallel sensp sensn led4 each 20ma 82m ? rtr020n05 2.2 f * rstb pwmpow pwmdrv power on/off 100hz~10khz pwm vbat led5 led6 failsel gnd 24k ? test gnd iseth vreg 1 f isetl gnd gnd can be set up to each 10~25ma 10 f batter y vdet sw led1 led2 led3 4.7 h 8led x 2 parallel sensp sensn led4 each 60ma 82m ? rtr020n05 2.2 f * rstb pwmpow pwmdrv power on/off 100hz~10khz pwm vbat led5 led6 failsel gnd 24k ? test gnd iseth vreg 1 f isetl gnd gnd can be set up to each 30~75ma fig.55 4 series ? 4 parallel, led current 20ma setting fig.56 8 series ? 2 parallel, led current 60ma setting current driver pwm application current driver pwm application 10 f batter y vdet sw led1 led2 led3 4.7 h 3led x 5 parallel sensp sensn led4 each 20ma 82m ? rtr020n05 2.2 f * rstb pwmpow pwmdrv power on/off 100hz~1khz pwm vbat led5 led6 failsel gnd 24k ? test gnd iseth vreg 1 f isetl gnd gnd can be set up to each 10~25ma fig.57 3 series ? 5 parallel, led current 20ma setting power control pwm application
technical note 24/26 www.rohm.com 2010.03 - rev.a ? 2010 rohm co., ltd. all rights reserved. BD6581GU ? led current setting controlled iseth resistor. 24k ? : 20ma 30k ? : 16ma 19.6k ? : 24.5ma 33k ? : 14.5ma ? brightness control please input pwm pulse from pwmpow or pwmdrv terminal. please refer electrical characteri stic p.3 and function (p.12). for the application of 22v and more for big current led 10 f batter y vdet sw led1 led2 led3 4.7 h 8led x 6 parallel sensp sensn led4 each 20ma 51m ? rtr020n05 2.2 f * rstb pwmpow pwmdrv power on/off 200h z pw m vbat led5 led6 failsel gnd 24k ? test gnd iseth vreg 1 f isetl gnd gnd 2.7~22v 1 f coil power supply 6~30v ic power supply can be set up to each 10~25ma 10 f batter y vdet sw led1 led2 led3 4.7 h 8led x 1 parallel sensp sensn led4 120ma 82m ? rtr020n05 2.2 f * rstb pwmpow pwmdrv power on/off 100hz~10khz pwm vbat led5 led6 failsel gnd 24k ? test gnd iseth vreg 1 f isetl gnd gnd can be set up to 60~150ma fig.58 fig.59 the separation of less than an ic power supply 5v and the coil power supply 10 f batter y vdet sw led1 led2 led3 4.7 h 10led x 6 parallel sensp sensn led4 each 20ma 51m ? rtr020n05 2.2 f * rstb pwmpow pwmdrv power on/off 200h z pw m vbat led5 led6 failsel gnd 24k ? test gnd iseth vreg 1 f isetl gnd gnd 2.7~5.5v 1 f can be set up to each 10~25ma coil power supply 6~30v ic power supply fig.60
technical note 25/26 www.rohm.com 2010.03 - rev.a ? 2010 rohm co., ltd. all rights reserved. BD6581GU control led current to charged d/a voltage. show application example and typ control. please decide final value after you ev aluated application, characteristic. 10 f batter y vdet sw led1 led2 led3 4.7 h 8led x 6 parallel sensp sensn led4 each 20ma 51m ? rtr020n05 2.2 f * rstb pwmpow pwmdrv power on/off vbat led5 led6 failsel gnd 470k ? test gnd iseth vreg 1 f isetl gnd gnd 24k ? d/a d/a led current 0.05v 19.4ma 0.2v 14.4ma 0.4v 7.7ma 0.5v 4.4ma 0.6v 1.0ma 0.7v 0ma led current = iset voltage 470k ? + iset voltage -d/ a 24k ? 800 typ led current = 0.6v 470k ? + 0.6v-d/a 24k ? 800 fig.61 analog style optical application
technical note 26/26 www.rohm.com 2010.03 - rev.a ? 2010 rohm co., ltd. all rights reserved. BD6581GU ordering part number b d 6 5 8 1 g u - e 2 part no. part no. package gu: vcsp85h2 packaging and forming specification e2: embossed tape and reel ? order quantity needs to be multiple of the minimum quantity. embossed carrier tape tape quantity direction of feed the direction is the 1pin of product is at the upper left when you hold reel on the left hand and you pull out the tape on the right hand 3000pcs e2 () direction of feed reel 1pin (unit : mm) vcsp85h2 (bu8920gu) s 0.08 s a b ba 0.05 1 2345 a b c d e ( 0.15)index post 1.0max 0.25 0.1 0.375 0.05 1pin mark 2.75 0.05 2.75 0.05 0.375 0.05 p=0.5 4 p=0.5 4 23- 0.30 0.05
r1010 a www.rohm.com ? 2010 rohm co., ltd. all rights reserved. notice rohm customer support system http://www.rohm.com/contact/ thank you for your accessing to rohm product informations. more detail product informations and catalogs are available, please contact us. notes no copying or reproduction of this document, in part or in whole, is permitted without the consent of rohm co.,ltd. the content specied herein is subject to change for improvement without notice. the content specied herein is for the purpose of introducing rohm's products (hereinafter "products"). if you wish to use any such product, please be sure to refer to the specications, which can be obtained from rohm upon request. examples of application circuits, circuit constants and any other information contained herein illustrate the standard usage and operations of the products. the peripheral conditions must be taken into account when designing circuits for mass production. great care was taken in ensuring the accuracy of the information specied in this document. however, should you incur any damage arising from any inaccuracy or misprint of such information, rohm shall bear no responsibility for such damage. the technical information specied herein is intended only to show the typical functions of and examples of application circuits for the products. rohm does not grant you, explicitly or implicitly, any license to use or exercise intellectual property or other rights held by rohm and other parties. rohm shall bear no responsibility whatsoever for any dispute arising from the use of such technical information. the products specied in this document are intended to be used with general-use electronic equipment or devices (such as audio visual equipment, ofce-automation equipment, commu- nication devices, electronic appliances and amusement devices). the products specied in this document are not designed to be radiation tolerant. while rohm always makes efforts to enhance the quality and reliability of its products, a product may fail or malfunction for a variety of reasons. please be sure to implement in your equipment using the products safety measures to guard against the possibility of physical injury, re or any other damage caused in the event of the failure of any product, such as derating, redunda ncy, re control and fail-safe designs. rohm shall bear no responsibility whatsoever for your use of any product outside of the prescribed scope or not in accordance with the instruction manual. the products are not designed or manufactured to be used with any equipment, device or system which requires an extremely high level of reliability the failure or malfunction of which may result in a direct threat to human life or create a risk of human injury (such as a medical instrument, transportation equipment, aerospac e machinery, nuclear-reactor controller, fuel- controller or other safety device). rohm shall bear no responsibility in any way for use of any of the products for the above special purposes. if a product is intended to be used for any such special purpose, please contact a rohm sales representative before purchasing. if you intend to export or ship overseas any product or technology specied herein that may be controlled under the foreign exchange and the foreign trade law, you will be required to obtain a license or permit under the law.

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