View BD8119FM-ME2_2004789.PDF datasheet online --- IC-ON-LINE

Datasheet File OCR Text:

1/20 www.rohm.com 2010.08 - rev. a ? 2010 rohm co., ltd. all rights reserved. power management ic series fo r automotive body control white backlight led driver for medium to large lcd panels (switching regulator type) bd8119fm-m description bd8119fm-m is a white led driver with the capability of withstanding high input voltage (36v max). this driver has 4ch constant-c urrent drivers integrated in 1-chip, which each channel can draw up to 150ma max, so that high brightness led driving can be realized. furthermore, a current-mode buck-boost dc/dc controller is al so integrated to achieve stable operation against unstable car-battery voltage input and also to remove the constr aint of the number of leds in series connection. the brightness can be controlled by either pwm or vdac techniques. features 1) input voltage range is 5.0 to 30 v 2) integrated buck-boost cu rrent-mode dc/dc controller 3) four integrated led current driver channels (150ma max. each channel) 4) pwm light modulation (minimum pulse width 25s) 5) built-in protection functions (uvlo, ovp, tsd, ocp, scp) 6) abnormal status detection function (open/ short) 7) hsop-m28 package applications backlight for car navigation, dashboard panels, etc. ( recommended component of toshiba matsushita display technology co.,ltd. ) absolute maximum ratings (ta=25 ) parameter symbol ratings unit power supply voltage v cc 36 v boot voltage v boot 41 v sw,cs,outh voltage v sw, v cs, v outh 36 v boot-sw voltage v boot-sw 7 v led output voltage v led1 4 36 v vreg, ovp, outl, fail1, fail2, leden1, leden2, iset, vdac, pwm, ss, comp, rt, sync, en voltage v vreg, v ovp, v outl, v fail1, v fail2, v leden1, v leden2, v iset, v vdac, v pwm, v ss, v comp, v rt, v sync, v en -0.3 7 < v cc v power consumption pd 2.20 1 w operating temperature range topr -40 +95 storage temperature range tstg -55 +150 led maximum output current i led 150 2 3 ma 1 ic mounted on glass epoxy board measuring 70mm70mm 1.6mm, power dissipated at a rate of 17.6mw/ at temperatures above 25 . 2 dispersion figures for led maximum output current and v f are correlated. please refer to data on separate sheet. 3 amount of current per channel. operating conditions (ta=25 ) parameter symbol ratings unit power supply voltage v cc 5.0 30 v oscillating frequency range f osc 250 550 khz external synchronization frequency range 4 5 f sync fosc 550 khz external synchronization pulse duty range f sduty 4060 % 4 connect sync to gnd or open when not using external frequency synchronization. 5 do not switch between internal and external synchronization when an external synchronization signal is input to the device. no.10039eat07
technical note 2/20 www.rohm.com 2010.08 - rev. a ? 2010 rohm co., ltd. all rights reserved. bd8119fm-m electrical characteristics (unless otherwise specified, v cc =12v ta=25 ) parameter symbol limits unit conditions min typ max. circuit current i cc - 7 14 ma en=hi, sync=hi, rt=open pwm=low, iset=open, c in =10f standby current i st - 4 8 a en=low [vreg block (vreg)] reference voltage v reg 4.5 5 5.5 v i reg =-5ma, c reg =2.2f [outh block] outh high-side on resistance r onhh 1.0 3 4.5 i on =-10ma outh low-side on resistance r onhl 0.5 2 3.0 i on =10ma over-current protection operating voltage v olimit v cc -0.66 v cc -0.6 v cc -0.54 v [outl block] outh high-side on resistance r onlh 1.0 3 4.5 i on =-10ma outh low -side on resistance r onll 0.5 2 3.0 i on =10ma [sw block] sw low -side on resistance r on_sw 1.0 2.0 4.0 i on_sw =10ma [error amplifie block] led voltage v led 0.9 1.0 1.1 v comp sink current i compsink 15 25 35 a v led =2v, vcomp=1v comp source current i compsource -35 -25 -15 a v led =0v, vcomp=1v [oscillator block] oscillating frequency f osc 250 300 350 khz r t =100k [ovp block] over-voltage detection reference voltage v ovp 1.9 2.0 2.1 v v ovp =sweep up ovp hysteresis width v ohys 0.45 0.55 0.65 v v ovp =sweep down scp latch off delay time t scp 70 100 130 ms r t =100k [uvlo block ] uvlo voltage v uvlo 4.0 4.3 4.6 v v cc : sweep down uvlo hysteresis width v uhys 50 150 150 mv v cc : sweep up this product is not designed for use in radioactive environments.
technical note 3/20 www.rohm.com 2010.08 - rev. a ? 2010 rohm co., ltd. all rights reserved. bd8119fm-m electrical characteristics ? continued (unless otherwise specified, vcc=12v ta=25 ) parameter symbol limits unit conditions min typ max. [led output block] led current relative dispersion width i led1 -3 - +3 % i led =50ma, i led1 =(i led i led_avg -1) 100 led current absolute dispersion width i led2 -5 - +5 % i led =50ma, i led2 =(i led 50ma-1) 100 iset voltage v iset 1.96 2.0 2.04 v riset 1=120k pwm minimum pulse width tmin 25 - - s f pwm =150hz, i led =50ma pwm maximum duty dmax - - 100 % f pwm =150hz, i led =50ma pwm frequency f pwm - - 20 khz duty=50%, i led =50ma vdac gain g vdac - 25 - ma/v v dac =0 2v, r iset =120k i led =vdac r iset gain open detection voltage v open 0.2 0.3 0.4 v v led = sweep down led short detection voltage v short 4.4 4.7 5.0 v v ovp = sweep up led short latch off delay time t short 70 100 130 ms rt=100k pwm latch off delay time t pwm 70 100 130 ms rt=100k [logic inputs (en, sync, pwm, leden1, leden2)] input high voltage v inh 2.1 - 5.5 v input low voltage v inl gnd - 0.8 v input current 1 i in 20 35 50 a v in =5v (sync, pwm, leden1, leden2) input current 2 i en 15 25 35 a v en =5v (en) [fail output (open drain) ] fail low voltage v ol - 0.1 0.2 v i ol =0.1ma this product is not designed for use in radioactive environments.
technical note 4/20 www.rohm.com 2010.08 - rev. a ? 2010 rohm co., ltd. all rights reserved. bd8119fm-m reference data (unless otherwise specified, ta=25 ) 0 2 4 6 8 10 012345 en voltage:ven [v] output voltage:vreg [v] 0.54 0.56 0.58 0.60 0.62 0.64 0.66 -40 -15 10 35 60 85 temperature:ta [ ] output voltage:vcc-vcs [v] 0 2 4 6 8 10 012345 pwm voltage:ven [v] outputcurrent :iled [ma] v cc =12v 45 47 49 51 53 55 -40 -15 10 35 60 85 temperature:ta [ ] outputcurrent :iled [ma] 0 1 2 3 4 5 0 0.02 0.04 0.06 0.08 0.1 vdac voltage:vdac[v] outputcurrent :iled [ma] 0 10 20 30 40 50 00.511.52 vdac voltage:vdac[v] outputcurrent :iled [ma] v cc = 12v 200 240 280 320 360 400 -40 -15 10 35 60 85 temperature:ta [ ] switching frequency:fosc [khz] 45 47 49 51 53 55 0.5 1.5 2.5 3.5 4.5 led voltage:vled[v] outputcurrent :iled [ma] 4.5 4.7 4.9 5.1 5.3 5.5 -40 -15 10 35 60 85 temperature:ta [ ] output voltage:vreg [v] fig.11 en threshold voltage fig.6 vdac gain fig.5 vdac gain fig.10 overcurrent detecting voltage temperature characteristic fig.1 vreg temperature characteristic fig.2 osc temperature characteristic fig.3 iled depend on vled fig.4 iled temperature characteristic v cc = 12v v cc =12v v cc =12v fig.7 efficiency (depend on input voltage) fig.8 efficiency (depend on output voltage) fig.9 circuit current (switching off) 25 40 55 70 85 100 25 150 275 400 525 output current [ma] efficiency [%] 25 40 55 70 85 100 25 150 275 400 525 output current [ma] efficiency [%] 0.0 2.0 4.0 6.0 8.0 10.0 0 6 12 18 24 30 36 supply voltage:vcc [v] output carrent:icc [ma] v cc =5v v cc =30v v cc =12v v cc =4v v cc =15v v cc =30v v cc =12v fig.12 pwm threshold voltage
technical note 5/20 www.rohm.com 2010.08 - rev. a ? 2010 rohm co., ltd. all rights reserved. bd8119fm-m block diagram fig.13 pin layout pin function table fig.14 pin symbol function 1 comp error amplifier output 2 ss soft start time-setting capacitance input 3 vcc input power supply 4 en enable input 5 rt oscillation frequency-setting resistance input 6 sync external synchronization signal input 7 gnd small-signal gnd 8 pwm pwm light modulation input 9 fail1 failure signal output 10 fail2 led open/short detection signal output 11 leden1 led output enable pin 1 12 leden2 led output enable pin 2 13 led1 led output 1 14 led2 led output 2 15 led3 led output 3 16 led4 led output 4 17 ovp over-voltage detection input 18 vdac dc variable light modulation input 19 iset led output current-setting resistance input 20 pgnd led output gnd 21 - n.c. 22 outl low-side external mosfet gate drive out put 23 dgnd low-side internal mosfet source out put 24 sw high-side external mosfet source pin 25 outh high-side external mosfet gate drive out pin 26 cs dc/dc current sense pin 27 boot high-side mosfet power supply pin 28 vreg internal reference voltage output comp 1 2 3 4 5 6 7 8 9 10 11 12 13 14 28 27 26 25 24 23 22 21 20 19 18 17 16 15 ss vcc en r t sync gnd pwm fail1 fail2 leden1 leden2 led2 led1 vreg boot cs outh sw dgnd outl n.c. pgnd iset vdac ovp led3 led4 dgnd rt comp err amp vin vreg vcc en rt ovp osc ss control logic uvlo tsd ss pwm led1 led2 led3 current driver iset pgnd pwm c in r pc c pc c ss cs r iset fail1 vreg vdac gnd iset led4 boot outh sw fail2 leden1 leden2 c out sync r pc crt ccomp vreg ovp timer latch pwm ocp drv ctl slope ocp ovp open short detect timer latch short det open det outl
technical note 6/20 www.rohm.com 2010.08 - rev. a ? 2010 rohm co., ltd. all rights reserved. bd8119fm-m 5v voltage reference (vreg) 5v (typ.) is generated from the v cc input voltage when the enable pin is set high. this voltage is used to power internal circuitry, as well as the voltage source for dev ice pins that need to be fixed to a logical high. uvlo protection is integrated into t he vreg pin. the voltage regulation circ uitry operates uninterrupted for output voltages higher than 4.5 v (typ.), but if output voltage drops to 4.3 v (typ.) or lower, uvlo engages and turns the ic off. connect a capacitor (creg = 2.2f typ.) to the vreg terminal for phase compensation. operation may become unstable if creg is not connected. constant-current led drivers if less than four constant-current drivers are used, unused channels should be sw itched off via the leden pin configuration. the truth table for these pins is shown below. if a driver output is enabled but not used (i.e. left open), the ic?s open circuit-detection circuitry will operate. please keep the unused pins open. the leden terminals are pulled down internally in the ic, so if left open, the ic will recognize them as logic lo. however, they should be connected directly to vreg or fixed to a logic hi when in use. led en led 1 2 1 2 3 4 l l on on on on h l on on on off l h on on off off h h on off off off ? output current setting led current is computed via the following equation: i led = min [ vdac , viset (=2.0v)] / rset x gain [a] (min[vdac , 2.0v] = the smaller value of either vd ac or viset; gain = set by internal circuitry.) in applications where an external signal is used for output current control, a control voltage in the range of 0.1 to 2.0 v can be connected on the vdac pin to control according to the abov e equation. if an external control signal is not used, connect the vdac pin to vreg (do not l eave the pin open as this may cause the ic to malfunction). also, do not switch individual channels on or off via the leden pin while operating in pwm mode. the following diagram illustrates the relation between iled and gain. in pwm intensity control mode, the on/off state of each current driver is controlled directly by the input signal on the pwm pin; thus, the duty ratio of the in put signal on the pwm pin equals the duty ratio of the led current. when not controlling intensity via pwm, fix the pwm terminal to a high vo ltage (100%). output light in tensity is greatest at 100% input. iled vs gain 2950 3000 3050 3100 3150 3200 3250 3300 3350 0 20 40 60 80 100 120 140 160 iled[ma] gain iled[ma] gain 10 3215 20 3080 30 3030 40 2995 50 3000 60 3020 70 3040 80 3070 90 3105 100 3140 110 3175 120 3210 130 3245 140 3280 150 3330 pwm iled(50ma/div) pwm iled pwm=150hz duty=50% pwm=150hz duty=0.38%
technical note 7/20 www.rohm.com 2010.08 - rev. a ? 2010 rohm co., ltd. all rights reserved. bd8119fm-m buck-boost dc/dc controller ? number of leds in series connection output voltage of the dcdc converter is co ntrolled such that the forward voltage ov er each of the le ds on the output is set to 1.0v (typ.). dcdc operation is performed only when the led output is operating. w hen two or more led outputs are operating simultaneously, the led volta ge output is held at 1.0v (typ.) per led over the column of leds with the highest vf value. the voltages of other led outputs are increased only in relation to the fluctuation of voltage over this column. consideration should be given to the change in powe r dissipation due to variations in vf of the leds. please determine the allowable maximum vf variance of the total le ds in series by using the description as shown below: vf variation allowable voltage 3.7v(typ.) = short detecti ng voltage 4.7v(typ.) - led control voltage 1.0v(typ.) the number of leds that can be connected in series is limited due to the open- circuit protection circuit, which engages at 85% of the set ovp voltage. therefore, the maximum output voltage of the under normal operation becomes 30.6 v (= 36 v x 0.85 , where ( 30.6 v ? 1.0 v) / vf > n [maximum number of leds in series]). ? over-voltage protection circuit (ovp) the output of the dcdc converter should be connected to t he ovp pin via a voltage divider. in determining an appropriate trigger voltage of for ovp function, consider the total number of leds in series and the maximum variation in vf. also, bear in mind that over-current protection (ocp) is triggered at 0.85 x ovp trigger voltage. if the ovp function engages, it will not release unless the dcdc voltage drops to 72. 5% of the ovp trigger voltag e. for example, if rovp1 (output voltage side), rovp2 (gnd side), and dcdc voltage vout are conditions for ovp, then: vout ( rovp1 + rovp2 ) / rovp2 x 2.0 v. ovp will engage when vout > 32 v if rovp1 = 330 k ? and rovp2 = 22 k ? . ? buck-boost dc/dc converter oscillation frequency (fosc) the regulator?s internal triangular wave oscillation frequency can be set via a resistor connected to the rt pin (pin 26). this resistor determines the charge/discharge current to the in ternal capacitor, thereby changing the oscillating frequency. refer to the following theore tical formula when setting rt: fosc = x [khz] 30 x 10 6 (v/a/s) is a constant (16.6%) determined by the internal circuitry, and is a correction factor that varies in relation to rt: { rt: = 50k ? : 0.98, 60k ? : 0.985, 70k? : 0.99, 80k ? : 0.994, 90k ? : 0.996, 100k ? : 1.0, 50k ? : 1.01, 200k ? : 1.02, 300k ? : 1.03, 400k ? : 1.04, 500k ? : 1.045 } a resistor in the range of 62.6k ? 523k ? is recommended. settings that deviate from the frequency range shown below may cause switching to stop, and proper operation cannot be guaranteed. fig.15 rt versus switching frequency ? external dc/dc converter oscillating frequency synchronization (fsync) do not switch from external to internal oscillation of the dc/dc converter if an external sync hronization signal is present on the sync pin. when the signal on the sync terminal is swit ched from high to low, a delay of about 30 s (typ.) occurs before the internal oscillation circuitry starts to operate (only the rising edge of t he input clock signal on the sync terminal is recognized). moreover, if external input frequenc y is less than the internal oscillation frequency, the internal oscillator will engage after the above-mentioned 30 s (typ .) delay; thus, do not input a synchronization signal with a frequency less than the internal oscillation frequency. 50k 150k 250k 350k 450k 550k 0 100 200 300 400 500 600 700 800 rt [k] ? [khz] 30 10 6 rt [ ] frequency
technical note 8/20 www.rohm.com 2010.08 - rev. a ? 2010 rohm co., ltd. all rights reserved. bd8119fm-m ? soft start function the soft-start (ss) limits the current and slows the rise-tim e of the output voltage during the start-up, and hence leads to prevention of the overshoot of the output voltage and the inrush current. ? self-diagnostic functions the operating status of the built -in protection circuitry is propagated to fai l1 and fail2 pins (open-drain outputs). fail1 becomes low when uvlo, tsd, ovp, or scp protection is engaged, whereas fail2 becomes low when open or short led is detected. ? operation of the protection circuitry ? under-voltage lock out (uvlo) the uvlo shuts down all the circuits other than reg when vcc ? 4.3v (typ). ? thermal shut down (tsd) the tsd shuts down all the circuits other than reg when the tj reaches 175 (typ), and releases when the tj becomes below 150 (typ). ? over current protection (ocp) the ocp detects the current through the power-fet by moni toring the voltage of the high-side resistor, and activates when the cs voltage becomes less than vcc-0.6v (typ). when the ocp is activated, the external capacitor of the ss pin becomes dischar ged and the switching operation of the dcdc turns off. ? over voltage protection (ovp) the output voltage of the dcdc is detected with the ovp-pin voltage, and the protection activates when the ovp-pin voltage becomes greater than 2.0v (typ). when the ovp is activated, the external capacitor of the ss pin becomes dischar ged and the switching operation of the dcdc turns off. ? short circuit protection (scp) when the led-pin voltage becomes less than 0.3v (typ), the inte rnal counter starts operating and latches off the circuit approximately after 100ms (when fosc = 300k hz). if the led-pin voltage becomes over 0.3v before 100ms, then the counter resets. when the led anode (i.e. dcdc output voltage) is shorted to ground, then the led current becomes off and the led-pin voltage becomes low. furthermore, the led current also becom es off when the led cathode is shorted to ground. hence in summary, the scp works with both cases of the led anode and the cathode being shorted. ? led open detection when the led-pin voltage ? 0.3v (typ) as well as ovp-pin voltage ? 1.7v (typ) simultaneously, the device detects as led open and latches off that particular channel. uvlo tsd ovp ocp s r q scp en=low uvlo/tsd fail1 en=low uvlo/tsd fail2 mask counter open short s r q
technical note 9/20 www.rohm.com 2010.08 - rev. a ? 2010 rohm co., ltd. all rights reserved. bd8119fm-m ? led short detection when the led-pin voltage ? 4.7v (typ) as well as ovp-pin voltage ? 1.6v (typ) simultaneously the internal counter starts operating, and approximately after 100ms (when fo sc = 300khz) the only detected channel (as led short) latches off. with the pwm brightness cont rol, the detecting operatio n is processed only when pwm-pin = high. if the condition of the detection operat ion is released before 100ms (when fosc = 300khz), then the internal counter resets. the counter frequency is the dcdc switching frequency determined by the rt. the latch proceeds at the count of 32770. protection detecting condition operation after detect [detect] [release] uvlo vreg<4.3v vreg>4.5v all blocks shut down tsd tj>175 tj<150 all blocks (but except reg) shut down ovp vovp>2.0v vovp<1.45v ss discharged ocp vcsQ vcc-0.6v vcs>vcc-0.6v ss discharged scp vled<0.3v (100ms delay when fosc=300khz) en or uvlo counter starts and then latches off all blocks (but except reg) led open vled<0.3v & vovp>1.7v en or uvlo the only detected channel latches off led short vled>4.7v & vovp<1.6v (100ms delay when fosc=300khz) en or uvlo the only detected channel latches off (after the counter sets)
technical note 10/20 www.rohm.com 2010.08 - rev. a ? 2010 rohm co., ltd. all rights reserved. bd8119fm-m protection sequence case for led2 in open-mode when vled2 0.3v and vovp 1.7v simultaneously, then led2 becomes off and fail2 becomes low case for led3 in short-mode when vled3 4.7v and vovp 1.6v simultaneously, then led3 becomes off after 100ms approx case for led4 in short to gnd -1 dcdc output voltage increases, and then ss dichages and fail1 becomes low -2 detects vled4<0.3v and shuts down after 100ms approx 1 turn on the en after the vcc is on 2 sync and pwm inputs are allowed to be on beforethe vcc is on 3 aprox 100ms of delay when fosc = 300khz vcc en uvlo vdac sync pwm ss iled1 iled2 iled3 iled4 vled1 vled2 vled3 vled4 vovp fail1 fail2 4.5v 1.0 <0.3 >4.7 100ms 3 0.3v 100ms 3 2.0v 1.7v 1 2 2 1 4 vreg
technical note 11/20 www.rohm.com 2010.08 - rev. a ? 2010 rohm co., ltd. all rights reserved. bd8119fm-m procedure for external components selection follow the steps as shown below for selecting the external components 1. work out il_max from the operating conditions. 2. select the value of rsc such that iocp > il_max 3. select the value of l such that 0.05/s < vout / l < 0.3v/ s 4. select coil, schottky diodes, mosfet and rcs which meet with the ratings 5. select the output capacitor which meets with the ripple voltage requirements 6. select the input capacitor 7. work on with the compensation circuit 8. work on with the over-voltage protection (ovp) setting 9. work on with the soft-start setting 10. verify experimentally feedback the value of l
technical note 12/20 www.rohm.com 2010.08 - rev. a ? 2010 rohm co., ltd. all rights reserved. bd8119fm-m 1. computation of the input peak current and il_max calculation of the maximu m output voltage (vout_max) to calculate the vout_max, it is necessary to take into acco unt of the vf variation and the number of led connection in series. vout_max = (vf + vf) n + 1.0v vf: vf variation n: number of led connection in series calculation of the output current iout iout = iled 1.05 m number of led connection in parallel calculation of the input peak current il_max il_max = il_avg + 1/2 il il_avg = (vin + vout) iout / (n vin) il= n: efficiency fosc: switching frequency ? the worst case scenario for vin is when it is at the mi nimum, and thus the minimum value should be applied in the equation. ? the l value of 10f ? 47f is recommended. the current-mode type of dc/dc conversion is adopted for bd8119fm-m, which is optimized with the use of t he recommended l value in the design st age. this recommendation is based upon the efficiency as well as the stability. the l values outside this recommended range may cause irregular switching waveform and hence deteriorate stable operation. ? n (efficiency) is approximately 80% external application circuit 2. the setting of over-current protection choose rcs with the use of the equat ion vocp_min (=0.54v) / rcs > il_max when investigating the margin, it is worth noting that the l value may vary by approximately 30%. 3. the selection of the l in order to achieve stable operation of the current-mode dc/dc converter, we recommend selecting the l value in the range indicated below: 0.05 [v/s] < < 0.3 [v/s] the smaller allows stability improvement but slows down the response time. 4. selection of coil l, diode d1 and d2, mosfet m1 and m2, and rcs current rating voltage rating heat loss coil l > il_max D diode d1 > iocp > vin_max diode d2 > iocp > vout mosfet m1 > iocp > vin_max mosfet m2 > iocp > vout rcs D D > iocp 2 rcs allow some margin, such as the tolerance of the external components, when selecting. in order to achieve fast switching, choose the mosfets with the smaller gate-capacitance. v in l 1 fosc vout v in +vout v in rcs d1 l d2 m2 m1 co vout i l cs vout rcs l vout rcs l
technical note 13/20 www.rohm.com 2010.08 - rev. a ? 2010 rohm co., ltd. all rights reserved. bd8119fm-m 5. selection of the output capacitor select the output capacitor cout based on th e requirement of the ripple voltage vpp. vpp = + il_min resr choose cout that allows the vpp to settl e within the requirement. allow some margin also, such as the tolerance of the external components. 6. selection of the input capacitor a capacitor at the input is also required as the peak current flows between the input and t he output in dc/dc conversion. we recommend an input capacitor greater than 10f with the esr smaller than 100m ? . the input capacitor outside of our recommendation may cause large ripple voltage at the input and hence le ad to malfunction. 7. phase compensation guidelines in general, the negative feedback loop is stable when the following condition is met: ? overall gain of 1 (0db) with a phase lag of less than 150o (i.e., a phase margin of 30o or more) however, as the dc/dc converter constantly samples the switching frequency, the gain-bandwidth (gbw) product of the entire series should be set to 1/10 the switching frequency of the system. therefore, the overall stability characteristics of the app lication are as follows: ? overall gain of 1 (0db) with a phase lag of less than 150o (i.e., a phase margin of 30o or more) ? gbw (frequency at gain 0db) of 1/10 the switching frequency thus, to improve response within the gbw product lim its, the switching frequency must be increased. the key for achieving stability is to place fz near to the gbw. phase-lead fz = [hz] phase-lag fp1 = [hz] good stability would be obtained when the fz is set between 1khz 10khz. in buck-boost applications, right-hand-plane (rhp) zero exists . this zero has no gain but a pole characteristic in terms of phase. as this zero would cause instability when it is in the control loop, so it is necessary to bring this zero before the gbw. frhp= [hz] i load : maximum load current it is important to keep in mind that t hese are very loose guidelines, and adjustments may have to be made to ensure stability in the actual circuitry. it is also important to note that stability characteristics can change greatly depending on factors such as substrate layout and load conditions. ther efore, when designing for mass-production, stability should be thoroughly investigated and confirme d in the actual physical design. 1 fosc 1 2 cpcrpc fb a comp v out rpc led cpc 1 2 rlcout 2 i load l vout+vin/(vout+vin) vout vout+v in iout cout
technical note 14/20 www.rohm.com 2010.08 - rev. a ? 2010 rohm co., ltd. all rights reserved. bd8119fm-m 8. setting of the over-voltage protection we recommend setting the over-voltage protection vovp 1.2v to 1.5v greater than vout which is adjusted by the number of leds in series connection. less than 1.2v may cause unexpected detection of the led open and short during the pwm brightness control. fo r the vovp greater than 1.5v, the led short detection may become invalid. 9. setting of the soft-start the soft-start allows minimization of the coil current as we ll as the overshoot of the out put voltage at the start-up. for the capacitance we recommend in the range of 0.001 ? 0.1f. for the capacitance less than 0.001f may cause overshoot of the output voltage. for the capacitance greater than 0.1f may cause massive reverse current through the parasitic elements of the ic and damage the whole device. in case it is necessary to use the capacitance greater than 0.1f, ensure to have a reverse current protection diode at the vcc or a bypa ss diode placed between the ss-pin and the vcc. soft-start time tss tss = cssx0.7v / 5a [s] css: the capacitance at the ss-pin 10 verification of the operation by taking measurements the overall characteristic may change by load current, input voltage, output voltage, i nductance, load capacitance, switching frequency, and the pcb layout. we strongly recommend verifying your design by taking the actual measurements. 2.0v/1.45v 1.7v/1.6v ovp vo rovp2 rovp1
technical note 15/20 www.rohm.com 2010.08 - rev. a ? 2010 rohm co., ltd. all rights reserved. bd8119fm-m power dissipation calculation power dissipation can be calculated as follows: pc(n) = icc*vcc + 2*ciss*vreg*fsw*vcc+[vled*n+ vf*(n-1)]*iled i cc maximum circuit current v cc supply power voltage c iss external fet capacitance v sw sw gate voltage f sw se frequency v led led control voltage n led parallel numeral v f led v f fluctuation i led led output current sample calculation: pc(4) = 10ma 30v + 500pf 5v 300khz 30v + [1.0v 4 + vf 3] 100ma vf = 3.0v, pc (4) = 322.5mw + 1.3w = 1622.5mw fig.16 note 1: power dissipation calculated when mounted on 70mm x 70 mm x 1.6mm glass epoxy substrate (1-layer platform/copper thickne ss 18m) note 2: power dissipation changes with the copper foil density of the board. the area of the copper foil becomes the total area of the heat radiation fin and the foot pattern (connected directly wi th ic) of this ic. this value represents only observed values, not guaranteed values. pd=2200mw ( 968mw): substrate copper foil density 3% pd=3200mw (1408mw): substrate copper foil density 34% pd=3500mw (1540mw): substrate copper foil density 60% (value within parentheses represents power dissipation when ta=95c) note 3: please design so that ambient te mperature + self-generation of heat may become 150 or less because this ic is tj=150 . note 4: please note the heat design because there is a possibilit y that thermal resistance rises from the examination result o f the temperature cycle by 20% or less. 0 500 1000 1500 2000 2500 00.511.522.533.5 led?Svf[v] iled=5 0ma iled=1 00ma iled=1 50ma power dissipation pd [mw] led fluctuation vf [v] ambient temperature ta[] 4 power dissipation pd[] 2 1 0 150 125 100 75 50 25 3 (3) 3.50w (2) 3.20w (1) 2.20w (1) ja=56.8/w (substrate copper foil density 3%) (2) ja=39.1/w (substrate copper foil density34%) (3) ja=35.7/w (substrate copper foil density60%) 95
technical note 16/20 www.rohm.com 2010.08 - rev. a ? 2010 rohm co., ltd. all rights reserved. bd8119fm-m the coupling capacitors cvcc and creg should be mounted as close as possible to the ic?s pins. large currents may pass through dgnd and pgnd, so each should have its own low-impedance routing to the system ground. noise should be minimized as much as possible on pins vdac, iset,rt and comp. pwm, sync and led1-4 carry switching signals, so ensure during layout that surrounding traces are not affected by crosstalk. 1. comp 2. ss 3. vcc 4. en 5. rt 6. sync 7. gnd fin. fin 8. pwm 9. fail1 10. fail2 11. leden1 12. leden2 13. led1 14. led2 28. vreg 27. boot 26. cs 25. outh 24. sw 23. dgnd 22. outl fin. fin 21. fbr 20. pgnd 19. iset 18. vdac 17. ovp 16. led4 15. led3 vcc vcc cin1 cin2 cpc2 cpc1 rpc1 css en sw1 crt rrt sync cin3 pwm rfl1 rfl2 vreg fail1 fail2 vreg sw2 sw3 led1 led2 led4 led3 vdac rdac vreg ciset riset d1 l1 d g m2 s cout1 cout2 d2 rovp1 rovp2 cbt creg m1 s d g rcs5 vreg vout ccs rcs1 rcs2 rcs3
technical note 17/20 www.rohm.com 2010.08 - rev. a ? 2010 rohm co., ltd. all rights reserved. bd8119fm-m application board part list serial no. component name component value product name manufacturer 1 cin1 10f grm31cb31e106ka75b murata 2 cin2 3 cin3 4 cpc1 0.1f 5 cpc2 murata 6 rpc1 510 ? 7 css 0.1f grm188b31h104ka92 murata 8 rrt 100k ? mcr03 series rohm 9 crt 10 rfl1 100k ? mcr03 series rohm 11 rfl2 100k ? mcr03 series rohm 12 ccs 13 rcs1 620m ? mcr100jzhfsr620 rohm 14 rcs2 620m ? mcr100jzhfsr620 rohm 15 rcs3 16 rcs5 0 ? 17 creg 2.2f grm188b31a225ke33 murata 18 cbt 0.1f grm188b31h104ka92 murata 19 m1 rss070n05 rohm 20 m2 rss070n05 rohm 21 d1 rb050l-40 rohm 22 d2 rf201l2s rohm 23 l1 33h cdrh105r330 sumida 24 cout1 10f grm31cb31e106ka75b murata 25 cout2 10f grm31cb31e106ka75b murata 26 rovp1 30k ? mcr03 series rohm 27 rovp2 360k ? mcr03 series rohm 28 riset 120k ? mcr03 series rohm 29 ciset 30 rdac 0 ? ? the above values are fixed numbers for confi rmed operation with the following conditions: v cc = 12v, four parallel channels of five series-connected leds, and iled=50ma. ? optimal values of external components depend on the actual ap plication; these values should only be used as guidelines and should be adjusted to fit the operating c onditions of the act ual application. when performing open/short tests of the external components, the open condition of d1 or d2 may cause permanent damage to the driver and/or the external components. in or der to prevent this, we recommend having parallel connections for d1 and d2.
technical note 18/20 www.rohm.com 2010.08 - rev. a ? 2010 rohm co., ltd. all rights reserved. bd8119fm-m input/output equivalent circuits (terminal name follows pin number) 1. comp 2. ss 4. en 5. rt 6. sync, 8. pwm 9. fail1, 10. fail2 11. leden1, 12. leden2 13. led1, 14. led2, 15. led3, 16. led4 17. ovp 18. vdac 19. iset 22. outl 24. sw 25. outh 26. cs 27. boot 28. vreg 21. all values typical. cs 5k vcc n.c. n.c. = no connection (open) 1k ss vcc vreg rt vreg 167 10k 3.3v 150k sync pwm 1k fail1 fail2 2.5k 5k led1 4 500 vdac vcc vreg 500 iset vcc 12.5 vreg vreg 100k outl vreg vreg boot sw vreg vcc vreg 205k 100k 10k 3.3v 150k leden1 leden2 10k comp 2k 2k vreg vreg en 175k 135k 10k vcc sw vcc boot 100k outh boot sw sw sw 5k ovp 10k vcc
technical note 19/20 www.rohm.com 2010.08 - rev. a ? 2010 rohm co., ltd. all rights reserved. bd8119fm-m notes for use 1) absolute maximum ratings use of the ic in excess of absolute maximum ratings (such as the input voltage or operating temperature range) may result in damage to the ic. assumptions should not be made regarding the state of the ic (e.g., short mode or open mode) when such damage is suffered. if operational values are expec ted to exceed the maximum ratings for the device, consider adding protective circuitry (such as fuses) to eliminate the risk of damaging the ic. 2) gnd potential ensure that the gnd pin is held at the minimum potential in all operating conditions. 3) thermal design use a thermal design that allows for a sufficient margin fo r power dissipation (pd) under actual operating conditions. 4) inter-pin shorts and mounting errors use caution when orienting and positioning the ic for mounting on printed circuit boards. improper mounting may result in damage to the ic. shorts between output pins or between output pins and the power supply and gnd pins caused by poor soldering or foreign objects may result in damage to the ic. 5) operation in strong electromagnetic fields exercise caution when using the ic in t he presence of strong electromagnetic fiel ds as doing so may cause the ic to malfunction. 6) testing on application boards when testing the ic on an application board, connecting a capaci tor directly to a low-impedance pin may subject the ic to stress. always discharge capacitors completely after each pr ocess or step. the ic?s power supply should always be turned off completely before connecting or removing it from a jig or fixture during the ev aluation process. to prevent damage from static discharge, ground the ic during assembly and use similar precautions during transport and storage. 7) ground wiring patterns when using both small-signal and large- current gnd traces, the two ground trac es should be routed separately but connected to a single ground potential within the application in order to avoid variat ions in the small-signal ground caused by large currents. also ensure that the gnd traces of external components do not cause variations on gnd voltage. 8) ic input pins and parasitic elements this monolithic ic contains p+ isolation a nd p substrate layers between adjacent elem ents in order to keep them isolated. pn junctions are formed at the intersection of these p layers with the n layers of other elements, creating parasitic diodes and/or transistors. for example (refer to the figure below): example of ic structure ? when gnd > pin a and gnd > pin b, the pn junction operates as a parasitic diode ? when gnd > pin b, the pn junction o perates as a parasitic transistor parasitic diodes occur inevitably in the structure of the ic, a nd the operation of these parasiti c diodes can result in mutual interference among circuits, operational faults, or physical dama ge. accordingly, conditions that cause these diodes to operate, such as applying a voltage lower than the gnd voltage to an input pin (and thus to the p substrate) should be avoided. 9) over-current protection circuits an over-current protection circuit (designed according to the output current) is integrated into the ic to prevent damage in the event of load shorting. this protection circuit is effective in preventing damage due to sudden and unexpected overloads on the output. however, the ic should not be used in applications where operat ion of the ocp function is anticipated or assumed 10) thermal shutdown circuit (tsd) this ic also incorporates a built-in tsd circuit for the prot ection from thermal destruction. the ic should be used within the specified power dissipation range. ho wever, in the event that the ic contin ues to be operated in excess of its power dissipation limits, the rise in the chip's junction temperature t j will trigger the tsd circuit, shutting off all output power elements. the circuit automatically resets itself once the junction temperature t j drops down to normal operating temperatures. the tsd protection will only engage when the ic's absolute maximum ratings have been exceeded; therefore, application designs should never atte mpt to purposely make use of the tsd function. pin a parasitic elements n n n p + p + p p substrate gnd parasitic element resistance n n p + p + p p substrate gnd p a r as i t i c el e m e n ts pin b transistor (npn) c b e n gnd pin a parasitic element pin b other adjacent elements e b c gnd
technical note 20/20 www.rohm.com 2010.08 - rev. a ? 2010 rohm co., ltd. all rights reserved. bd8119fm-m ordering part number b d 8 1 1 9 f m - m e 2 part no. part no. package fm: hsop-m28 type 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 1500pcs e2 () direction of feed reel 1pin (unit : mm) hsop-m28 (max 18.85 include burr) 0.8 7.5 0.2 15 5.15 0.1 0.11 1.25 2.2 0.1 1 18.5 0.2 0.5 0.2 0.37 0.1 9.9 0.3 4 +6 ?4 28 1.2 0.15 14 0.27 +0.1 ?0.05 s 0.1 s
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.

▲Up To Search▲

Price & Availability of BD8119FM-ME2

	To Download BD8119FM-ME2 Datasheet File
If you can't view the Datasheet, Please click here to try to view without PDF Reader .