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product structure silicon monolithic integrated circuit ? this product has no designed protec tion against radioactive rays 1/34 datashee t 4.dec.2013 rev.003 ? 2013 rohm co., ltd. all rights reserved. tsz22111 k 15k 001 www.rohm.com tsz02201-0g3g0c600010-1-2 4ch white led driver with buck-boost and built-in fet (32 led maximum) BD81A04AMUV-M bd81a04aefv-m general description BD81A04AMUV-M/efv-m is a white led driver with the capability of withstanding high input voltage (40v max). this driver has 4ch constant-current drivers integrat ed in 1-chip, where each channel can draw up to 120ma (max), which is also suitable for high illumination led drive. furthermore, a buck-boost current mode dc/dc controller is also integrat ed to achieve stable operation during power voltage fluctuation. light modulation (dimming function) is possible by pwm input. the nch mosfet for power surge is also integrated in the ch ip, thereby saving spaces of board sets. features ? integrated buck-boost curr ent mode dc/dc controller ? integrated 4ch current driver for led drive ? pwm light modulation (dimming)-supported ? external switching frequency synchronization ? built-in protection function (uvlo, ovp, ocp, scp) ? led abnormality detection function (open/short) ? integrated v out discharge function (buck-boost structure limitation) ? aec-q100 qualified application audio display, small and medium type lcd panels for automotive use. key specifications ? operating input voltage range ? output led current accuracy ? dc/dc oscillation frequency ? operating temperature range ? led maximum output current 4.5 to 35 v 3.0%@50ma 200 to 2200khz -40 to +125 120ma/ch package w(typ) x d(typ) x h(max) application circuit diagram r rt comp v in vcc en rt ovp ss pwm led 1 led 2 iset pgnd c in r pc c pc c ss cs r iset fail 1 vreg boot sw fail 2 leden 1 c out sync led 3 led 4 outl dgnd vdisc outh leden 2 shdeten gnd ( dgnd ) ( dgnd ) ( gnd ) ( gnd ) (gnd ) ( gnd ) (gnd ) ( gnd ) (gnd ) ( dgnd ) ( gnd ) ( dgnd ) ( pgnd ) BD81A04AMUV-M / bd81a04aefv-m figure 1. buck-boost application circuit vout vqfn28sv5050 BD81A04AMUV-M 5.00mm x 5.00mm x 1.00mm htssop-b28 bd81a04aefv-m 9.70mm x 6.40mm x 1.00mm
2/34 datasheet datasheet BD81A04AMUV-M bd81a04aefv-m tsz02201-0g3g0c600010-1-2 ? 2013 rohm co., ltd. all rights reserved. 4.dec.2013 rev.003 www.rohm.com tsz22111 ~ 15~ 001 pin configuration pin description vqfn28sv5050 (top view) htssop-b28 (top view) block diagram vqfn28 sv5050 htssop -b28 terminal pin name function 1 11 leden1 led output pin enable terminal 1 2 12 leden2 led output pin enable terminal 2 3 13 led1 led output terminal 1 4 14 led2 led output terminal 2 5 15 led3 led output terminal 3 6 16 led4 led output terminal 4 7 17 ovp over-voltage detection terminal 8 18 iset led output current setting terminal 9 19 pgnd led output gnd terminal 10 20 outl low side fet drain terminal 11 21 dgnd dc/dc output gnd terminal 12 22 vdisc output voltage discharge terminal 13 23 sw high side fet source terminal 14 24 outh high side fet gate terminal 15 25 boot high side fet drive r power supply terminal 16 26 vreg internal constant voltage 17 27 en enable terminal 18 28 cs dc/dc current sense terminal 19 1 vcc input power supply terminal 20 2 ss ?soft start? capacitor connection 21 3 comp err amp output 22 4 rt oscillation frequency-setting resistance input 23 5 sync external synchronization signal input terminal 24 6 shdeten short detection enable signal 25 7 gnd small signal gnd terminal 26 8 pwm pwm light modulation input terminal 27 9 fail1 ?failure? signal output terminal 28 10 fail2 led open/shor t detection output signal - - thermal ? pad back side thermal pad (please connect to gnd) comp err amp vreg vcc en rt ovp osc ss control logic uvlo tsd ss pwm led1 led2 current driver iset pgnd pwm cs fail1 vreg iset boot sw fail2 leden1 sync vreg ovp timer latch pwm ocp drv ctl slope ocp ovp open short detect timer latch short det open det led3 led4 outl dgnd outh leden2 shdeten gnd vdisc figure 3. internal block ? figure 2. pin placement ?
3/34 datasheet datasheet BD81A04AMUV-M bd81a04aefv-m tsz02201-0g3g0c600010-1-2 ? 2013 rohm co., ltd. all rights reserved. 4.dec.2013 rev.003 www.rohm.com tsz22111 ~ 15~ 001 absolute maximum ratings (ta=25c) item code rating unit power supply voltage v cc 40 v boot, outh pin voltage v boot , v outh 45 v sw, cs, outl pin voltage v sw , v cs , v outl 40 v boot-sw pin voltage v boot-sw 7 v led1 to 4, vdisc pin voltage v led1,2,3,4 , v vdisc 40 v vreg, ovp, fail1, fail2, leden1, leden2 iset, pwm, ss, comp, rt, sync, en, shdeten pin voltage v vreg , v ovp , v fail1 , v fail2 , v leden1 , v leden2 , v iset , v pwm , v ss , v comp , v rt , v sync , v en , v shdeten -0.3 to +7 < v cc v power dissipation (vqfn28sv5050) pd(muv) 4.56 (note 1) w power dissipation (htssop-b28) pd(efv) 4.70 (note 2) w operating temp range topr -40 to +125 c storage temp range tstg -55 to +150 c led maximum output current i led 120 (note 3) ma junction temperature tjmax 150 c note 1 mounted on a 4-layer 70mm70mm1.6mm glass epoxy pcb and gold foil area 70mm70mm. decrease by 36.5mw/ for ta above 25 . note 2 mounted on a 4-layer 70mm70mm1.6mm glass epoxy pcb and al l layers heat radiation gold foil 5505mm2. decrease by 37.6mw / for ta above 25 . note 3 current level/ch caution: operating the ic over the absolute maximum ratings ma y damage the ic. in addi tion, it is impossibl e to predict all des tructive situations such as short-circuit modes, open circuit modes, etc. therefore, it is important to consider circuit protection measures, like adding a fuse, in case the ic is operated in a special mode exceeding the absolute maximum ratings recommended operating conditions (ta=25c) item code rating unit power supply voltage v cc 4.5 to 35 v dc/dc oscillation frequency range fosc 200 to 2200 khz external synchronization frequency range (note 4) (note 5) f sync fosc to 2200 khz external synchronization pulse duty range f sduty 40 to 60 % note 4 if not using an external synchronization frequency, please make the sync open and/or connect to gnd. note 5 if using an external synchronization frequency, please do not conduct the operation such as switching to internal oscil lation frequency in the middle of the process.
4/34 datasheet datasheet BD81A04AMUV-M bd81a04aefv-m tsz02201-0g3g0c600010-1-2 ? 2013 rohm co., ltd. all rights reserved. 4.dec.2013 rev.003 www.rohm.com tsz22111 ~ 15~ 001 electrical characteristics (v cc =12v, ta = tj = -40c to +125c *unless otherwise specified) parameter symbol limits unit conditions min normal max circuit current i cc - - 10 ma en=high, sync=high, rt=open pwm=low, iset=open,c in =10 f standby current i st - - 10 a en=low, vdisc=open [vreg] reference voltage v reg 4.5 5.0 5.5 v i reg =-5ma, c reg =2.2 f [outh] outh high side on-resistance r onhh 1.9 3.5 6.2 ? i on =-10ma, ta=25c 1.5 3.5 7.0 ? i on =-10ma, ta=-40c to +125c outh low side on-resistance r onhl 1.0 2.5 5.0 ? i on =10ma, ta=25c 0.8 2.5 5.5 ? i on =10ma, ta=-40c to +125c ocp detection voltage v olimit v cc -0.66 v cc -0.6 v cc -0.54 v [outl] outl high side on-resistance r onl 0.44 0.8 1.15 ? i on =10ma, ta=25c 0.20 0.8 2.10 ? i on =10ma, ta=-40c to +125c [sw] sw low side on-resistance r on_sw 5.0 10.0 15.0 ? i on =10ma, ta=25c 4.0 10.0 25.0 ? i on =10ma, ta=-40c to +125c [error amp] led control voltage v led 0.9 1.0 1.1 v comp sink current i compsink 20 80 160 a v led =2v, v comp =1v comp source current i compsource -160 -80 -20 a v led =0v, v comp =1v [oscillator] oscillation frequency 1 fosc1 285 300 315 khz r t =27k ? oscillation frequency 2 fosc2 1800 2000 2200 khz r t =3.9k ? [ovp] ovp detection voltage v ovp1 1.9 2.0 2.1 v v ovp =sweep up ovp hysteresis width v ovphys1 0.45 0.55 0.65 v v ovp =sweep down pre-boost detection voltage v ovp2 0.9 1.0 1.1 v v ovp =sweep up pre-boost hysteresis width v ovphys2 0.33 0.43 0.53 v v ovp =sweep down
5/34 datasheet datasheet BD81A04AMUV-M bd81a04aefv-m tsz02201-0g3g0c600010-1-2 ? 2013 rohm co., ltd. all rights reserved. 4.dec.2013 rev.003 www.rohm.com tsz22111 ~ 15~ 001 electrical characteristics (v cc =12v, ta = tj = -40c to +125c *unless otherwise specified.) - continued parameter symbol limits unit conditions min normal max [uvlo] uvlo detection voltage v uvlo 3.2 3.5 3.8 v v cc : sweep down uvlo hysteresis width v uhys 250 500 750 mv v cc : sweep up, vreg>3.5v [led output] led current relative dispersion i led1 -3 - +3 % i led =50ma, ta=25c ? i led1 =(i led /i led_avg -1)100 -5 - +5 % i led =50ma, ta=-40c to +125c ? i led1 =(i led /i led_avg -1)100 led current absolute dispersion i led2 -3 - +3 % i led =50ma, ta=25c ? i led2 =(i led /50ma-1)100 -5 - +5 % i led =50ma, ta=-40c to +125c ? i led2 =(i led /50ma-1)100 iset voltage v iset 0.9 1.0 1.1 v r iset =100k ? pwm minimum pulse width t min 20 - - s f pwm =150hz, i led =100ma pwm maximum duty d max - - 100 % f pwm =150hz, i led =50ma pwm frequency f pwm - - 20 khz duty=2%, i led =50ma [protection circuit] led open detection voltage v open 0.2 0.3 0.4 v v led = sweep down led short detection voltage v short 4.2 4.5 4.8 v v led = sweep up led short detection latch off delay time t short 70 100 130 ms r rt =27k ? pwm latch off delay time t pwm 70 100 130 ms r rt =27k ? scp latch off delay time t scp 70 100 130 ms r rt =27k ? [logic input] input high voltage v inh 2.1 - v reg v input low voltage v inl gnd - 0.8 v input current i in 15 50 100 a v in =5v(en,sync,pwm,leden1, leden2) [fail output (open drain)] fail low voltage v ol - 0.1 0.2 v i ol =0.1 6/34 datasheet datasheet BD81A04AMUV-M bd81a04aefv-m tsz02201-0g3g0c600010-1-2 ? 2013 rohm co., ltd. all rights reserved. 4.dec.2013 rev.003 www.rohm.com tsz22111 ~ 15~ 001 typical performance curves 1000 1500 2000 2500 3000 -60 -20 20 60 100 140 temperature ta[ ] swiching frequency fosc[khz] 200 250 300 350 400 -60 -20 20 60 100 140 temperature ta[ ] swiching frequency fosc[khz] figure 5. output voltage vs temperature figure 6. switching frequency vs temperature (@300khz) 0 2 4 6 8 010203040 supply voltage vcc[v] output current icc [ma ] vcc=4.5 to 35v en=4v pwm=0v ta = 2 5 ? vcc=12v en=4v rt=27k
figure 4. circuit current vs supply voltage ? figure 7. switching frequency vs temperature (@2000khz) vcc=12v en=4v rt=3.9k
circuit current :i cc [ma] ? supply voltage : v cc [v] ? 3.5 4.0 4.5 5.0 5.5 -60 -20 20 60 100 140 tempurature ta[ ] output voltage vreg[v] vcc=12v,35v vcc=4.5v
7/34 datasheet datasheet BD81A04AMUV-M bd81a04aefv-m tsz02201-0g3g0c600010-1-2 ? 2013 rohm co., ltd. all rights reserved. 4.dec.2013 rev.003 www.rohm.com tsz22111 ~ 15~ 001 typical performance curves - continued 48 49 50 51 52 -60 -20 20 60 100 140 temperature ta[ ] output current iled[ma] 60 65 70 75 80 85 90 95 100 80 130 180 230 output current iled[ma] efficiency [%] 48 49 50 51 52 012345 supply voltage vled[v] output current iled[ma] figure 8. output current vs supply voltage figure 9. output current vs temperature figure 10. efficiency vs output current (buck-boost application) vcc=12v en=4v vled 1 2v pwm 1vreg vcc=12v,en=4v vled=sweep ta = 2 5 ? 60 65 70 75 80 85 90 95 100 80 130 180 230 output current iled[ma] efficiency [%] figure 11. efficiency vs output current (boost application) vcc=12v en=4v pwm=v reg ta = 2 5 ? 7-led series, 4ch mode vcc=12v en=4v pwm=vreg ta = 2 5 ? 4-led series, 4ch mode supply voltage : v led [v] ? out p ut current :i led [ ma ] ? output current : i led [ma] ? output current : i led [ma] ? efficienc y :[%] ? efficienc y : [ % ] ?
8/34 datasheet datasheet BD81A04AMUV-M bd81a04aefv-m tsz02201-0g3g0c600010-1-2 ? 2013 rohm co., ltd. all rights reserved. 4.dec.2013 rev.003 www.rohm.com tsz22111 ~ 15~ 001 80 90 100 110 120 -40 -25 -10 5 20 35 50 65 80 95 110 125 iled [ma] ta [ ? ] ta vs iled ? vout=50mv ? vout=100mv ? vout=200mv description of blocks 1. voltage reference (v reg ) 5v (typ) is generated from the v cc input voltage (when at en=high). this voltage (v reg ) is used as power supply of internal circuit and when fixing the pins outside of the ic at a high voltage, as well. the uvlo protection is integrated in v reg . the circuit starts to operate at v cc ? 4.0v (typ) and v reg =3.5v (typ) and stops when at v cc 3.5v (typ) or v reg 2.0v (typ). for release/cancellation condition and detection condition, please refer to table 2 on page 11. connect a capacitor (c reg =2.2 f)(typ) to vreg terminal for phase compensation. if the c reg is not connected, the oper ation of circuit will be notably unstable. 2. constant current driver table1. led control logic leden1 leden2 led1 led2 led3 led4 l l on on on on h l on on on off l h on on off off h h on off off off if less than four constant-current driv ers are used, please make the led1~4 te rminal ?open? while the output ?off? by leden1 and leden2 terminal. the truth table for these pins is shown above. if the unused cons tant-current driver output will be set open without the process of le den1,2 terminals, the ?open detection? will be activated. the leden1, 2 terminals is pulled down internally in the ic and it is low at ?open? co ndition. however, they should be connected to vreg terminal or fixed to a logic high when in use. (1) output current setting ????????? figure 12. i led vs r iset the output current i led can be obtained by the following equation: ? precaution during current setting ? if the output current i led is set to >100ma/ch, the stability of led current within specified operat ing temperature range will decrease. led current supply value will depend on the amount of ripple in output voltage (v out ). the figure below shows the temperature and the possible led current maximum value setting, please adjust the ripple voltage in such a way that the led current value setting will fall within the range as shown on the graph below. ( ? v out output ripple voltage) figure 13. temperature (ta) vs output led current (i led ) : () typ gain 5000 = [] [] ( ) gain k r v ma i iset led = 0 . 1
9/34 datasheet datasheet BD81A04AMUV-M bd81a04aefv-m tsz02201-0g3g0c600010-1-2 ? 2013 rohm co., ltd. all rights reserved. 4.dec.2013 rev.003 www.rohm.com tsz22111 ~ 15~ 001 (2) pwm intensity control figure 14. pwm=150hz, duty=0.02%, i led waveform figure 15. pwm=150hz, duty=50.0%, i led waveform the current driver on/off of pwm dimmer is controlled in pwm terminal. the duty ratio of pwm terminal becomes duty ratio of i led . if pwm terminal is not conducted 100%, please set the pwm terminal fixed at high. output light intensity is greatest at 100% input. 3. buck-boost dc/dc controller (1) number of led in series connection in this chip, the output voltage of the dc/ dc converter is controlled in such a way t hat the forward voltage over each of the led on the output is set 1.0v (typ). t he dc/dc operation is activated only when led output is operating. when two or more led are operating at the same time, the led voltage output is held at 1.0v (typ) per led over the column of led with the highest forward voltage. then t he voltages of other led output within same column will increased only in relation to the fluctuation of voltage. enough consideration should be given to the change in power dissipation due to vf variations of leds. please determine the allowable maximum vf variance of the total leds in series by using the description as shown below: vf variation tolerance voltage 3.5v (typ) = short detection voltage 4.5v (typ) led control voltage 1.0v (typ) in addition, the 81.5% of ovp voltage setting is the ?trigger? of ?open detection (falling)?. the maximum value of ovp terminal output voltage is calculated as follows. 40v (dc/dc output maximum ra ting voltage) 0.815 = 32.6v following this, the number of led series is set in such a way the equation below can be met. (max number of led series) ? (2) over voltage protection circuit (ovp) the output of the dc/dc converte r should be connected to the ovp pin via vo ltage divider. in determining an appropriate trigger voltage for ovp function, consider the total number of leds in series and t he maximum variation in vf. also, bear in mind that led open detection is triggered at 0.815 x ovp trigger voltage. when ovp terminal voltage drops to 1.45v (typ) after ovp operation, the ovp will be released or cancelled. if r ovp1 (gnd side), r ovp2 (output voltage side) and output voltage v out , below is the equation: v out [v] R(r ovp1 [k ? ] + r ovp2 ) [k ? ] / r ovp1 [k ? ] x 2.0v ovp will engage when v out >32v if r ovp1 =22k ? and r ovp2 =330k ? . pwm(2v/div) i led (50ma/div) pwm(2v/div) i led (50ma/div) 500ns / div 1ms / div ( )[] > ? v v f 1 . 1 6 . 32 v
10/34 datasheet datasheet BD81A04AMUV-M bd81a04aefv-m tsz02201-0g3g0c600010-1-2 ? 2013 rohm co., ltd. all rights reserved. 4.dec.2013 rev.003 www.rohm.com tsz22111 ~ 15~ 001 100 1000 10000 110100 fosc [khz] rrt[k ] rrt vs fosc (3) buck-boost dc/dc converter oscillation frequency (fosc) figure 16. fosc vs r rt the regulator?s internal triangular wave oscillation frequency c an be set via a resistor connected to the rt pin (pin 4). this resistor determines the charge/discharge current to the internal capacitor, ther eby changing the oscillating frequency. please set the resistance of r rt using the data mentioned above and the logical equation mentioned below as reference. where: 8110 5 is the constant value in ic (+-5%) . is the adjustment factor (r t :. = 41k : 1.01, 27k : 1.00 , 18k : 0.99, 10 k : 0.98, 4.7k : 0.97, 3.9k : 0.96 ) a resistor in the range of 3 k to 41 k is recommended. settings that deviate from the frequency range shown above may cause switching to stop, and proper operation cannot be guaranteed. (4) external synchronization oscillation frequency (f sync ) the clock signal input to sync terminal can be performed from the outside therefore the internal oscillation frequency can be synchronized externally. do not switch from external to internal oscillation of the dc/dc converter if an ex ternal synchronization signal is present on the sync pin and the clock input to sync terminal is valid only in rising edge. as for the external input frequency, the input of the internal oscillation frequency 20% decided in rt terminal resistance is recommended. (5) soft start function (ss) the soft-start (ss) limits the cu rrent and slows the rise-time of the output voltage during t he start-up, and hence leads to prevention of the overshoot of the output voltage and the inrush current. if yo u don?t use soft-start function, please set ss terminal open. for the computation of ss ti me, please refer to the formula on page 19. [] [] ( ) = kr khzfosc rt 5 1081
11/34 datasheet datasheet BD81A04AMUV-M bd81a04aefv-m tsz02201-0g3g0c600010-1-2 ? 2013 rohm co., ltd. all rights reserved. 4.dec.2013 rev.003 www.rohm.com tsz22111 ~ 15~ 001 4. self-check function table 2. detection condition of each protecti on function and the operation during detection protection function detection condition operation during detection [detection ] [release/ cancellation] uvlo v cc <3.5v or v reg <2.0v v cc >4.0v and v reg >3.5v all blocks shuts down (except for vreg) tsd tj>175c tj<150c all blocks shuts down (except for vreg) ovp v ovp >2.0v v ovp <1.45v ss pin discharged ocp v cs Qv cc -0.6v v cs >v cc -0.6v ss pin discharged scp v led <0.3v or v ovp <0.57v (100ms delay @300khz) en or uvlo delay counter starts and then latches off all blocks (except for vreg) led open protection v led <0.3v & v ovp >1.8v en or uvlo only the detected channel latches off led short protection v led >4.5v (100ms delay @300khz) en or uvlo only the detected channel latches off (after the counter starts ) note1. the fail1 and fail2 output is reset when en=low ? high or uvlo detection ? release/ cancel en 1 low or uvlo detection are unfixed. figure 17. protection flag output block diagram the operating status of the built-in protection circuitry is propagated to fail1 and fail2 terminals (open-drain outputs). fail1 becomes low when tsd, ovp, ocp, or scp protec tion is engaged, whereas fail2 becomes low when open or short led is detected. if the fail terminal will not be used as flag output, please make the fail terminal open or connect it to gnd. but if the fail terminal will be used as a flag output, it is recommended to pull-up the fail1, 2 terminals to vreg terminal. (1) under-voltage lock out (uvlo) the uvlo shuts down all the circuits other than v reg when v cc <3.5v(typ) or v reg <2.0v(typ) (2) thermal shut down (tsd) the tsd shuts down all the circuits other than v reg when the tj reaches 175c ? (typ), and releases when the tj becomes below 150c ? (typ). (3) over-current protection (ocp) the ocp detects the current through the power-fet by monitoring the voltage of the high-side resistor, and activates when the cs voltage becomes less than v cc -0.6v (typ). when the ocp is activated, the external capacitor of the ss terminal becomes discharged and the switching operation of the dc/dc turns off. (4) over-voltage protection (ovp) the output voltage of dc/dc is detected from the ovp terminal voltage, and th e over-voltage protection will activate if the ovp terminal voltage becomes greater than 2.0v (typ). when ovp is activated, the external capacitor of the ss terminal becomes discharged and the switching operation of the dc/dc turns off. f a il1 f a il2 en=l o w o r u vl o en=low or uvlo fail1 fail2
12/34 datasheet datasheet BD81A04AMUV-M bd81a04aefv-m tsz02201-0g3g0c600010-1-2 ? 2013 rohm co., ltd. all rights reserved. 4.dec.2013 rev.003 www.rohm.com tsz22111 ~ 15~ 001 (5) short circuit protection (scp) when the led terminal voltage becomes less than 0.3v (typ), the internal counter starts operating and latches off the circuit approximately after 100ms (when fosc = 300khz). if the led terminal voltage becomes over 0.3v before 100ms, then the counter resets. when the led anode (i.e. dc/dc output voltage) is shorted to ground, then the led current becomes off and the led terminal voltage becomes low. furthermore, the led current also becomes 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. (6) led open detection when the led terminal voltage is below 0.3v (typ) as well as ovp terminal vo ltage >1.8v (typ) simultaneously, the device detects as led open and latches off that particular channel. (7) pwm low interval detection circuit after the en loading, the low interval of pwm input is coun ted by built-in counter. the cl ock frequency of counter is the fosc frequency, which is determined by r rt , and stops the operation of circuits other than vreg at 32768 count. for fosc=300khz, it becomes ?pwm low interval detection? after 100ms. (8) output voltage discharge circuit (vdisc terminal) restarting dc/dc must be operated after discharging v out . if using only pull-down resistance as setting ovp for discharging, it takes a lot time for discharging v out . therefore this product has functi onality of circuit for discharge. when v disc terminal is connected to output of dc/dc, the output can be discharged when dccd circuit become off (with en changing high to low or detection of protect). the discharge time t disc is expressed in the following equations. t disc [s] typ = c out [f] v out [v] / 0.33 t disc [s] max = c out [f] v out [v] / 0.192 where: t disc : dc/dc output discharge time c out : dc/dc output capacity v out : dc/dc output voltage in the discharge of residual charge, it will take some t disc time. for en re-loading, conduct after the time from off of dc/dc circuit to t disc (or higher) is opened. (9) led short detection circuit if the led terminal voltage becomes >4.5v (typ), the built-in counter operation will start and the latch will activate at oscillation frequency in 32770 count. in case of fosc=300kh z, it becomes ?latch off? only with corresponding led series after 100ms. during ?pwm light modulation?, the led short detection operati on is carried out only when pwm=high. if the led short detection ?condition? is released/ cancelled while counter is running, the counter will reset and will return to normal operating condition. when led s hort detection function will not be used, shdeten should be connected to vreg before starting therefore turning o ff of short detection function. when led short detection function is used, the shdeten should be connected to g nd. in addition, the switch ing of shdeten=high/low can be made during normal operation.
13/34 datasheet datasheet BD81A04AMUV-M bd81a04aefv-m tsz02201-0g3g0c600010-1-2 ? 2013 rohm co., ltd. all rights reserved. 4.dec.2013 rev.003 www.rohm.com tsz22111 ~ 15~ 001 timing chart figure 18. protection sequence timing chart note 1 ? turn on en after v cc reaches the operating voltage range. note 2 ? the order of turning on pwm and sync is arbitrary. note 3 ? approximately 100ms of delay when fosc=300khz. note 4 the tss expresses the time from uvlo release/cancel until the start of dc/dc swit ching. (details on page 19) note 5 ? the timing chart is defined when pulling ?up the fail pin towards the vreg. 1. in between v ovp <1.0v, regardless it is pwm input, the dc/dc switch ing operation will be carried out (pre-voltage). by the v ovp R 1.0v, the pre-voltage ends. 2. the led2 is open mode. vled2 ? 0.3v and v ovp ? 1.8v are detected and led2 is turned off. fail2 becomes low 3. led3 is short mode vled3 ? 4.5v is detected and after 100ms, the (@fosc=300khz) led3 will turn off. 4. vled4 is shorted to gnd. (1) output voltage high, and ovp is detected with v ovp ? 2.0v. ss discharged and fail1 becomes low. (2) after detection of vled4 ? 0.3v, shutdown after about 100ms (@fosc=300khz).
14/34 datasheet datasheet BD81A04AMUV-M bd81a04aefv-m tsz02201-0g3g0c600010-1-2 ? 2013 rohm co., ltd. all rights reserved. 4.dec.2013 rev.003 www.rohm.com tsz22111 ~ 15~ 001 procedure for external components selection follow the steps as shown below for selecting the external components. 1. computation of input peak current i l_max from application condition 2. set the rcs value so that it becomes i ocp >i l_max 3. select the value of l so that it becomes 0.05v/ s< ???k r cs <1.9xfosc [mhz] 4. select the coil, schottky diode, mosfet and r cs which meets the current and voltage ratings. 5. select the output capacitor which meets with the ripple voltage requirements 6. select the input capacitor 7. phase compensation circuit selection 8. over-voltage protection selection 10. soft start time selection 11. actual operation confirmation v out l 9. pre-boost selection l value is feed back
15/34 datasheet datasheet BD81A04AMUV-M bd81a04aefv-m tsz02201-0g3g0c600010-1-2 ? 2013 rohm co., ltd. all rights reserved. 4.dec.2013 rev.003 www.rohm.com tsz22111 ~ 15~ 001 1. input peak current i l_max computation in case of buck-boost application figure 19. output application circuit diagram (1) max output voltage (v out_max ) computation consider the vf variation and number of led connection in series for v out_max derivation where: v out_max [v] is the max output voltage vf [v] is the led vf voltage ? vf is the led vf voltage variation n is the no. of led series (2) max output current i out_max computation where: i out_max [a]: max input peak current i led [a]: output current/ch. m no. of led parallel (3) max input peak current i l_max computation where: i l_max [a]: max input peak current i l_avg [a]: max input average current il[a] input current amplification where: v in [v] input voltage n: efficiency fosc switching frequency l [h]: coil value (a) the worst case scenario for v in is when it is at the minimum, and thus the minimum value should be applied in the equation.. (b) the l value of 2.2 to 47 h is recommended. the current-mode ty pe of dc/dc conversion is adopted for BD81A04AMUV-M and bd81a04aefv-m, which is optimized with the use of the recommended l value in the design stage. this recommendation is based upon the efficiency as well as t he stability. the l values outside this recommended range may cause irregular switching waveform and hence deteriorate stable operation. (c) n (efficiency) becomes almost 80%. v in rcs d1 l d2 outl m1 cout vout i l cs sw outh ic internal () vnvfvf v max out 1.1 _ ++= m i i led max out = 03.1 _ il ii avgl maxl += 2/1 _ _ ( ) () in max out max out in avgl vn i vvi += / _ _ _ out in out in vv v foscl v il + = 1 v in v out c out
16/34 datasheet datasheet BD81A04AMUV-M bd81a04aefv-m tsz02201-0g3g0c600010-1-2 ? 2013 rohm co., ltd. all rights reserved. 4.dec.2013 rev.003 www.rohm.com tsz22111 ~ 15~ 001 2. setting of over-current protection value please select the r cs value so that it becomes 3. selection of the l inductor in order to achieve stable operation of the ?current mode dc/dc converter?, we recommend selecting the l value in the range indicated below. since there is almost 30% variation in the value of coil l, keep enough margin and set. the smaller allows stability improvement but slows down the response time. 4. selection of coil l, diode d1, d2, mosfet m1, r cs and c out current rating voltage rating heat loss coil l > i l_max D diode d1 > i ocp > v in_max diode d2 > i ocp > v ovp_max mosfet m1 > i ocp > v in_max r cs D D > i ocp 2 r cs c out D >v ovp_max D t please consider external parts deviation and make the setting with enough margin. t? in order to achieve fast switching, choose th e mosfet?s with the smaller gate-capacitance. 5 . ? selection of output capacitor select the output capacitor c out based on the requirement of the ripple voltage v pp . choose c out that allows the v pp to settle within the requirement. allow some margin also, such as the tolerance of the external components. 6. ? selection of input capacitor a capacitor at the input is also required as the peak curr ent flows between the input and t he output in dc/dc conversion. we recommend an input capacitor greater than 10 f with the esr smaller than 100m . the input capacitor outside of our recommendation may cause large ripple voltage at the input and hence lead to malfunction. 7. phase compensation circuit guidelines figure 20. comp application circuit diagram about application stability condition the stability in led voltage feedback system is achieved when the following conditions are met. (1) the phase delay when gain is 1(0db) is below 150c (or simply, phase margin >30c). (2) the frequency (unity gain frequency) when gain is 1(0db) is <1/10 of switching frequency. [] [ ] [ ] [] [] mhzfosc hl rvv sv cs out < ? < 9.1 /05.0 l rv cs out [] [] [] [] [] [] [] [] [] ? + + = resrai hzfoscvvvv vv fc ai vv maxl in out out out out pp _ 1 [] () [] [] airvvv maxl cs min ocp _ _ 54.0 >?= fb a comp v out rpc led cpc v out r pc c pc
17/34 datasheet datasheet BD81A04AMUV-M bd81a04aefv-m tsz02201-0g3g0c600010-1-2 ? 2013 rohm co., ltd. all rights reserved. 4.dec.2013 rev.003 www.rohm.com tsz22111 ~ 15~ 001 one way to assure stability based on phase compensation is phase advancement close to frequency and fz insertion. in addition, the phase delay fp1 shall be decided based on c out and output impedance r l . respective formula shall be as follows. phase-lead ??????????????????? phase-lag 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 zero characteristic for gain and pole characteristic in terms of phase. as this zero would cause instability when it is in the control loop, so it is necessary to ke ep rhp frequency more than gbw frequency. where: i load : max load current it is important to keep in mind that these are very l oose 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. therefore, when designing for mass-production, stability should be thoroughly investigated and confirm ed in the actual physical design. 8. setting of over-voltage protection(ovp) over-voltage protection (ovp) is set from the external resistance r ovp1 and r ovp2 . the setting described below will be important in the either boost, buck, buck-boost applications. figure 21. ovp application circuit the ovp terminal detects the over-voltage when at >2.0v (typ) and stops the dc/dc operation. in addition, it detects the open condition when ovp terminal is at >1.8v (typ) and led1 to 4 pin voltage is at <0.3v (typ), and the circuit is latched to off (please refer to page 11, self-check function). in preven ting error in detection of open, it is necessary that the resistor partial pressure voltage of the maximum value of output voltage shall be less than the min value of open detection voltage. please set the r ovp1 and r ovp2 is such a way the formula shown below can be met. where: v out is the dc/dc output voltage v open is the ovp pin open detection voltage sample 1: when v f =3.2v0.3v led is used in 8series v out (max) = 1.1v(led control voltage max) + (3.2v + 0.3v) 8 = 29.1v open detection ovp pin voltage v open (min) = 1.7v if r ovp1 =20k ? , please set by r ovp2 > 322.3k ? from (1) t? the output impedance calculated from [] [] [] = rpcfcpc hzfz 2 1 [] [] [] fcr hzfp out l = 2 1 1 out out l i v r = () ( ) () ( ) ( ) 1 2 1 1 ? minvrrrmaxv open ovp ovp ovp out <+ [] () [] [][] hlai vvvv hzfrhp load in out in out 2 2 + = 2.0v/1. 45v 1.8v/1.7v ovp r ovp2 r ovp1 vou t ic internal 1. 0v / 0 .57 v
18/34 datasheet datasheet BD81A04AMUV-M bd81a04aefv-m tsz02201-0g3g0c600010-1-2 ? 2013 rohm co., ltd. all rights reserved. 4.dec.2013 rev.003 www.rohm.com tsz22111 ~ 15~ 001 sample 2: vf=3.2v0.3v led is used in 3series v out (max) = 1.1v (led control voltage max) + (3.2v + 0.3v) 3 = 11.6v open detection ovp pin voltage v open (min) = 1.7v if r ovp1 =20k ? , please set by r ovp2 > 116.5k ? from (1). 9. setting of pre-boost voltage (ovp) ovp circuit detects abnormality in dc/dc output start-up when ovp pin voltage is below 1.0v (typ). to shorten the starting time at low pwm duty condition, as far as pre-boost condition (dc/dc not starting at 1.0v (typ)) is con cerned, the ovp pin will carry out a 100% switching without relying on pwm duty. for this, to be able to carry-out the normal pwm modul ation, it would be important that the output voltage minimum value of ovp resistance voltage shall exceed the pre-boost setting ovp volta ge maximum value. please conduct the setting for r ovp1 and r ovp2 in such a way it meets the formula below. where: v out dc/dc output voltage ? v ovp ovp pre-boost voltage setting sample 1: if the led of v f =3.2v0.3vis used in the 8series v out (min) = 0.9v (led control voltage min) + (3.2v ? 0.3v) 8 = 24.1v pre-boost voltage setting v ovp (max) = 1.1v if r ovp1 =20k ? , it would be important to conduct setting by r ovp2 < 418.2k ? from (2). sample 2: if the led of v f =3.2v0.3vis used in the 3series v out (min) = 0.9v (led control voltage min) + (3.v ? 0.3v) 3 = 9.6v pre-voltage voltage setting v ovp (max) = 1.1v if r ovp1 =20k ? , it would be important to conduct setting by r ovp2 < 154.5k ? from (2). ?in case of v f =3.2v0.5v, 8series, r ovp1 =20k ? and r ovp2 =360k ? ? ?in case of v f =3.2v0.5v, 3series, r ovp1 =20k ? and r ovp2 =130k ? ? figure 22. ovp terminal voltage operation model (8series) figure 23. ovp terminal voltage operation model (3series) () ( ) () ( ) ( ) 2 2 1 1 ? maxvrrrminv ovp ovp ovp ovp out >+ the variations of led load vf must be within this range. v ovp v ovp v ovp v ovp v ovp v ovp
19/34 datasheet datasheet BD81A04AMUV-M bd81a04aefv-m tsz02201-0g3g0c600010-1-2 ? 2013 rohm co., ltd. all rights reserved. 4.dec.2013 rev.003 www.rohm.com tsz22111 ~ 15~ 001 there is a presence of pre-boost by initial voltage of v out from the ovp terminal voltage setting and application construction. shown below is the presence of pre-boost operation upon start. 10. setting of soft start the soft start circuit minimizes the coil current at the input and overshoot at the output vo ltage during the start-up conditio n. a capacitance in the range of 0.001 to 0. 1f is recommended. a capacitance of le ss than 0.001f may cause overshoot at the output voltage. however, a capacitanc e greater than 0.1f may cause massive reverse current through the parasitic elements when power supply is off and may damage the ic. in ca se, that it is necessary to use a capacitance greater than 0.1f, ensure to have a reverse current protection diode at the v cc or a bypass diode between the ss pin and v cc pin soft start time (the time from e n loading and pwm loading up to start of dc/dc switching) t ss (typ) where; c ss : the capacitance at ss terminal figure 25. pre-boost model (v out initial value is below 0.57v (typ)) figure 24. not a pre-boost model (v out initial value is above 0.57v (typ)) [] [ ] [] [ ] avfcst ss ss 5/7.0 =
20/34 datasheet datasheet BD81A04AMUV-M bd81a04aefv-m tsz02201-0g3g0c600010-1-2 ? 2013 rohm co., ltd. all rights reserved. 4.dec.2013 rev.003 www.rohm.com tsz22111 ~ 15~ 001 in c ss setting and dc/dc oscillation frequency setting, there is a possi bility that grounding protection will take time during start-up. this is occurring since grounding is detected before start-up when the start-ti me of dc/dc output due to c ss setting becomes bigger than the time extension of grounding protection taking time. please check the following setting of c ss and oscillating frequency. where: trise: dc/dc output start-up time ? v1: ic constant voltage (max 2.0v) ? i ss : ss source current (min 2.0 a) where: tscp: scp latch off delay time fosc: dc/dc oscillating frequency scp error detection avoidance condition: trise < tscp 11. verification of the operation by taking measurements the overall characteristics may change based on load current, i nput voltage, output voltage, in ductance, load capacitance, switching frequency, and pcb layout. we strongly recommend verifying your design by taking the actual measurements. [] [ ] [ ] [ ] aivvfcstrise ss ss 1 = [ ] () [ ] hz fosc s t scp 1 32770 =
21/34 datasheet datasheet BD81A04AMUV-M bd81a04aefv-m tsz02201-0g3g0c600010-1-2 ? 2013 rohm co., ltd. all rights reserved. 4.dec.2013 rev.003 www.rohm.com tsz22111 ~ 15~ 001 vcc [v] vout [v] 35 4.5 32 12 9 35 i/o recommended operating range the i/o recommended operating range (v cc vs v out ) of BD81A04AMUV-M/efv-m is shown as follows. the graphs below are the recommended operating range of output voltage (v out ) for the input voltage (v cc ). the data mentioned below is the reference data for rohm evaluation board. so please always check the behavior of the evaluation board before using this ic. . figure 26. boost, fosc=300khz and i led =360ma operating range figure 27. boost, fosc=300khz and i led =200ma operating range figure 28. boost, fosc=2200khz and i led =360ma operating range figure 29. boost, fosc=2200khz and i led =200ma operating range figure 30. buck-boost, fosc=300khz, i led =360ma operating range figure 31. buck-boost, fosc=300khz, i led =200ma operating range figure 32. buck-boost, fosc=2200khz, i led =360ma operating range figur e 33. buck-boost, fosc=2200khz, i led =200ma operating range recommended operating range recommended operating range recommended operating range recommended operating range recommended operating range recommended operating range recommended operating range recommended operating range boost fosc=300khz i led =360< a buck-boost fosc=2200khz i led =200< a buck-boost fosc=2200khz i led =360< a buck-boost fosc=300khz i led =200< a buck-boost fosc=300khz i led =360< a boost fosc=2200khz i led =360< a boost fosc=2200khz i led =200< a boost fosc=300khz i led =200< a v cc [v] v cc [v] v cc [v] v cc [v] v cc [v] v cc [v] v cc [v] v cc [v] v out [v] v out [v] v out [v] v out [v] v out [v] v out [v] v out [v] v out [v] 35 6 32 22 4 . 5 35 recommended operating range 10 20 30 10 20 30 35 5 32 15 4 .5 35 recommended operating range 10 20 30 10 20 30 35 4 .5 7 .5 15 35 recommended operating range 10 20 30 10 20 30 32 20 30 10 20 30 10 20 30 10 20 30 10 20 30 10 20 30 10 20 30 20 30 10 20 30 10 20 30
22/34 datasheet datasheet BD81A04AMUV-M bd81a04aefv-m tsz02201-0g3g0c600010-1-2 ? 2013 rohm co., ltd. all rights reserved. 4.dec.2013 rev.003 www.rohm.com tsz22111 ~ 15~ 001 pcb application circuit figure 34. pcb application circuit 1. set the r rt resistance right near the rt terminal and do not put a capacitor. 2. set the r iset resistance right near the iset terminal pin and do not put a capacitor. 3. as much as possible, please put the coupling capacitors of c vcc and c reg as close as possible to the ic terminal pin. 4. large current may pass through d gnd and p gnd, so routing low impedance to the system ground. 5. noise should be minimized as much as possible on pwm, iset, and comp pins. 6. pwm, outh, sw, sync and led1-4 carry switching signals, pl ease be careful so that the surrounding pattern is not affected by crosstalk. 7. there is a heat radiation pad at the back of the package. please solder heat radiation pad with the board. 8. please make the buck fet (m1) gate resistance (rg1) into 0 ? . when resistance is connected, the off timing is delayed at rg1 and m1 parasitic capacitance will have large current that will flow through internal transistor of m1 and sw. by this large current, detection of ocp will occur. 9. in relation to boost loop d2 cout1 dgndm2 d2 and buck loop vcc rcs m1 d1 dgndgnd cin1 vcc) for the reduction of noise, please study and cons ider board layout at shor test minimum impedance.
23/34 datasheet datasheet BD81A04AMUV-M bd81a04aefv-m tsz02201-0g3g0c600010-1-2 ? 2013 rohm co., ltd. all rights reserved. 4.dec.2013 rev.003 www.rohm.com tsz22111 ~ 15~ 001 pcb board external components list serial no. component name component value product name manufacturer 1 cin1 10 f grm31cb31e106ka75b murata 2 cin2 (open) - - 3 cpc1 0.1 f grm188b31h104ka92 murata 4 cpc2 (open) - - 5 rpc1 510 ? mcr03 series rohm 6 css 0.01 f grm188b31h104ka92 murata 7 rrt 27k ? mcr03 series rohm 8 rfl1 100k ? mcr03 series rohm 9 rfl2 100k ? mcr03 series rohm 10 ccs (open) - - 11 rcs1 620m ? mcr100 series rohm 12 rcs2 620m ? mcr100 series rohm 13 rcs3 0 ? - - 14 creg 2.2 f grm188b31a225ke33 murata 15 cpc3 0.1 f grm188b31h104ka92 murata 16 m1 - rsh070n05 rohm 17 m2 (open) - - 18 d1 - rb050l-40 rohm 19 d2 - rb050l-40 rohm 20 l1 33 h slf10145t-330m1r6-h tdk 21 l2 (open) - - 22 cout1 10 f grm31cb31e106ka75b murata 23 cout2 10 f grm31cb31e106ka75b murata 24 cout3 (open) - - 25 rovp1 30k ? mcr03 series rohm 26 rovp2 360k ? mcr03 series rohm 27 riset 100k ? mcr03 series rohm 28 rg1 0 ? - - 29 rg2 (open) - - 30 jp1 0 ? - - 31 jp2 (open) - - 32 jp3 0 ? - - 33 jp4 0 ? - - 34 jp5 (open) - -
24/34 datasheet datasheet BD81A04AMUV-M bd81a04aefv-m tsz02201-0g3g0c600010-1-2 ? 2013 rohm co., ltd. all rights reserved. 4.dec.2013 rev.003 www.rohm.com tsz22111 ~ 15~ 001 application board circuit when using it as boost dc/dc converter figure 35. boost application circuit note: when using as boost dc/dc converter, if the v out and led terminal are shorted, the over-current from v in cannot be prevented. to prevent overcurrent, carry out m easure such as inserting fuse in between v cc and r cs . in case there is a current capacity towards each input te rminal of en, pwm, leden1, leden2, sync, please insert a limit resistance in between each terminals. when using it as buck dc/dc converter figure 36. buck application circuit
25/34 datasheet datasheet BD81A04AMUV-M bd81a04aefv-m tsz02201-0g3g0c600010-1-2 ? 2013 rohm co., ltd. all rights reserved. 4.dec.2013 rev.003 www.rohm.com tsz22111 ~ 15~ 001 additional parts for emc . 1. this part adjusts ?slew rate? of high side fet. (parts ex. r=mcr03 series 4.7 ) 2. this part decreases noise of curr ent loop of high side fet. (parts ex. c=0.01uf//1000pf) 3. this part decreases spectrum of high frequency on power line. (parts ex. c=0.01uf//1000pf) 4. this low pass filter decreases noise of power line. (parts ex. l=6.8uf, c=10uf) 5. this common mode filter decreases noise of power line. (parts ex. cmf=acm70v, c=0.1uf//0.01uf) 6. this chip beas decreases ringing of switching for low side fet. (parts ex. mpz2012s101a) 7. this snubber circuit decreases spectrum of high frequency of low side fet. (parts ex. r=mcr10 series 10 , c=100pf) 8. this snubber circuit decreases ringing of switching for low side fet. (parts ex. r=mcr10 series 10 , c=100pf) figure 37. application parts for emc vin bd81a04amuv/efv-m rrt comp vcc en rt ss pwm led1 led2 iset pgnd rpc cpc css cs riset fail1 vreg boot sw fail2 leden1 cout sync led3 led4 outl dgnd vdisc outh leden2 gnd (dgnd) (gnd) (gnd) (gnd) (gnd) (gnd) (gnd) (gnd) (dgnd) (gnd) (dgnd) (pgnd) ovp (dgnd) cin (dgnd) shdeten
26/34 datasheet datasheet BD81A04AMUV-M bd81a04aefv-m tsz02201-0g3g0c600010-1-2 ? 2013 rohm co., ltd. all rights reserved. 4.dec.2013 rev.003 www.rohm.com tsz22111 ~ 15~ 001 attention point for pcb layout the layout pattern influences characteristic, such as efficiency and a ripple greatly. so, it is necessary to examine carefully about it. boost dc/dc has ?loop1? (in figure 38). placement of these parts should be compact. and wiring should be low-impedance (e.g. cout?s gnd and dgnd should be very near). also, back-boost dc/dc has ?loop2?. placement of these parts and wiring should be compact and low-impedance (e.g. cin?s gnd and d1?s gnd should be very near). v in rcs l d2 outl m1 vout cs sw outh bd81a04aefv d1 cout cin dgnd dgnd-pin rcs d1 d2 cin cout m1 figure 39. bd81a04aefv pcb top-layer figure 38. circuit of dc/dc block outl-pin
27/34 datasheet datasheet BD81A04AMUV-M bd81a04aefv-m tsz02201-0g3g0c600010-1-2 ? 2013 rohm co., ltd. all rights reserved. 4.dec.2013 rev.003 www.rohm.com tsz22111 ~ 15~ 001 calculation of power consumption pc?? = i cc v cc ~~~ circuit power c iss1 vregf sw vreg ~~~ boost fet(built-in) drive step power c iss2 vregf sw vreg ~~~ buck fet(externally installed) drive step power { v led m + v f (m-1) }i led ~~~ current driver power r on feti fet i fet ~~~ built-in fet power i l_avg = (v cc +v out )/v cc i out /n ~~~ inductance average current i fet = i l_avg v out /(v cc +v out ) ~~~ current flowing through boost fet(built-in) i out = i led 1.03m ~~~ led output current v out = (v f +? v f )n v led ~~~ dc/dc output voltage pc[w] ic power consumption i cc [a] max circuit current v cc [v] power supply voltage c iss1 [f] boost fet gate capacitance c iss2 [f] buck fet gate capacity vreg[v] vreg voltage f sw [hz] switching frequency v led [v] led control voltage i led [a] led output current n number of led in series m number of led series in parallel v f [v] led forward voltage v f [v] led v f difference r on fet[ ? ] boost fet on- resistance n efficiency ? sample calculation ? i cc =10ma, v cc =12v, c iss1 =65pf, c iss2 =2000pf, vreg=5v, f sw =2200khz, v led =1v, i led =50ma, n=7series, m=4channel, ? if v f =3.5v, ? v f =0.5v, r on fet=1.15 ? , n=80% v out = (3.5v+0.5v)7series 1v = 29v i out = 50ma1.034channel = 0.206a i l_avg = (12+29v)/12v0.206a/0.8 = 0.88a i fet = 0.88a29v/(12v+29v)=0.622a pc (4) = 10ma12v ? + ? 65pf5v2200khz5v ? + ? 2000pf5v2200khz5v ? + 1.0v4+0.5v(4-1) ? 50ma ? + ? 1.15? 0.622a0.622a ?? = 0.953[w] will be the result. the above mentioned is a simple calculation and someti mes the value may differ from the actual value.
28/34 datasheet datasheet BD81A04AMUV-M bd81a04aefv-m tsz02201-0g3g0c600010-1-2 ? 2013 rohm co., ltd. all rights reserved. 4.dec.2013 rev.003 www.rohm.com tsz22111 ~ 15~ 001 i/o equivalent circuit 2.ss 3.comp 4.rt 5.sync,6.shdeten,8.pwm ,11.leden1,12.leden2 9.fail1,10.fail2 1316. led14 17.ovp 18.iset 20.outl 22.vdisc 23.sw 24.outh 25.boot 26.vreg 27.en 28.cs ss vcc 10k 1k vreg vreg 1k comp vreg 5k 1k vreg rt vreg 1k 12.5 vreg 10k vreg 100k vcc vcc sw 5p 5k 166 en vcc vdisc cs comp shdeten pwm leden1 leden2 125k 125k 1.1k 2p iset vreg 1k 1k sw vcc outh boot 1k boot sw boot sw sw boot vreg sw vreg vcc sw fail1 fail2 1k vreg 2 10k 100k vreg 90k led1 led2 led3 led4 vreg ovp 10k 10k 10k 10k 10k outl fail1 fail2 1k BD81A04AMUV-M bd81a04aefv-m t all values will become typ value.
29/34 datasheet datasheet BD81A04AMUV-M bd81a04aefv-m tsz02201-0g3g0c600010-1-2 ? 2013 rohm co., ltd. all rights reserved. 4.dec.2013 rev.003 www.rohm.com tsz22111 ~ 15~ 001 operational notes 1. reverse connection of power supply connecting the power supply in reverse polarity can damage the ic. take precautions against reverse polarity when connecting the power supply, such as mounting an external diode between the power supply and the ic?s power supply terminals. 2. power supply lines design the pcb layout pattern to provide low impedance ground and supply lines. separate the ground and supply lines of the digital and analog blocks to prevent noise in the ground and supply lines of the digital block from affecting the analog block. furthermore, connect a capacitor to ground at all power supply pins. consider the effect of temperature and aging on the capacitance val ue when using electrolytic capacitors. 3. gnd voltage ensure that no pins are at a voltage below that of t he ground pin at any time, even during transient condition. 4. ground wiring pattern when using both small-signal and large-current ground traces , the two ground traces should be routed separately but connected to a single ground at the refe rence point of the application board to av oid fluctuations in the small-signal ground caused by large currents. also ensure that the ground traces of external compon ents do not cause variations on the ground voltage. the ground lines must be as short and thick as possible to reduce line impedance. 5. thermal consideration should by any chance the power dissipation rating be exceeded, the rise in temperature of the chip may result in deterioration of the properties of the ch ip. the absolute maximum rating of the pd stated in this specification is when the ic is mounted on a 70mm x 70mm x 1.6mm glass epoxy board. in case of exceeding this absolute maximum rating, increase the board size and copper area to prevent exceeding the pd rating. 6. recommended operating conditions these conditions represent a range within which the expect ed characteristics of the ic can be approximately obtained. the electrical characteristics are guaranteed under the conditions of each parameter. 7. inrush current when power is first supplied to the ic, it is possible that the internal logic may be unstable and inrush current may flow instantaneously due to the internal powering sequence and delays, especially if the ic has more than one power supply. therefore, give special cons ideration to power coupling capacitance, po wer wiring, width of ground wiring, and routing of connections. 8. operation under strong electromagnetic field operating the ic in the presence of a strong electromagnetic field may cause the ic to malfunction. 9. testing on application boards when testing the ic on an application board, connecting a ca pacitor directly to a low-impedance output pin may subject the ic to stress. always discharge capacitors completely after each process or step. the ic?s power supply should always be turned off completely before connecting or removi ng it from the test setup duri ng the inspection process. to prevent damage from static discharge, ground the ic durin g assembly and use similar precautions during transport and storage. 10. inter-pin short and mounting errors ensure that the direction and position are correct when mounting the ic on the pc b. incorrect mounting may result in damaging the ic. avoid nearby pins being shorted to each other especially to ground, power supply and output pin. inter-pin shorts could be due to many reasons such as metal particles, water droplets (in very humid environment) and unintentional solder bridge deposited in between pins during assembly to name a few. 11. unused input terminals input termina ls of an ic are often connected to the gate of a mo s transistor. the gate has extremely high impedance and extremely low capacitance. if left unconnected, the electr ic field from the outside can easily charge it. the small charge acquired in this way is enough to produce a signifi cant effect on the conducti on through the transistor and cause unexpected operation of the ic. so unless otherwise specified, unused i nput terminals should be connected to the power supply or ground line. 12. regarding input pins of the ic this monolithic ic contains p+ isolation and p substrat e layers between adjacent elements in order to keep them isolated. p-n junctions are formed at the intersection of the p layers with the n layers of other elements, creating a parasitic diode or transistor. for example (refer to figure below): when gnd > pin a and gnd > pin b, the p-n junction operates as a parasitic diode. when gnd > pin b, the p-n junction operates as a parasitic transistor.
30/34 datasheet datasheet BD81A04AMUV-M bd81a04aefv-m tsz02201-0g3g0c600010-1-2 ? 2013 rohm co., ltd. all rights reserved. 4.dec.2013 rev.003 www.rohm.com tsz22111 ~ 15~ 001 parasitic diodes inevitably occur in the structure of the ic . the operation of parasitic diodes can result in mutual interference among circuits, operational faults, or physical damage. therefore, 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. figure 40. parasitic element 13. area of safe operation (aso) operate the ic such that th e output voltage, output current, and power dissipation are all within the area of safe operation (aso). 14. thermal shutdown circuit(tsd) this ic has a built-in thermal shutdown circuit that prevent s heat damage to the ic. normal operation should always be within the ic?s power dissipation rating. if however the rating is exceeded for a continued period, the junction temperature (tj) will rise which will activate the tsd circuit that will turn off all output pins. when the tj falls below the tsd threshold, the circuits are automatically restored to normal operation. note that the tsd circuit operates in a situation that exceeds the absolute ma ximum ratings and therefore, under no circumstances, should the tsd circuit be used in a set design or for any purpose other than protecting the ic from heat damage.
31/34 datasheet datasheet BD81A04AMUV-M bd81a04aefv-m tsz02201-0g3g0c600010-1-2 ? 2013 rohm co., ltd. all rights reserved. 4.dec.2013 rev.003 www.rohm.com tsz22111 ~ 15~ 001 ordering information bd81a04amuv - me2 package muv:vqfn28sv5050 packaging m: high reliability design e2: reeled, embossed taping (vqfn28sv5050) bd81a04aefv - me2 package efv:htssop-b28 packaging m: high reliability design e2: reeled, embossed taping (htssop-b28) marking diagram htssop-b28 (top view) bd81a04aefv part number marking lot number 1pin mark vqfn28sv5050 (top view) bd81a04amuv part number marking lot number 1pin mark
32/34 datasheet datasheet BD81A04AMUV-M bd81a04aefv-m tsz02201-0g3g0c600010-1-2 ? 2013 rohm co., ltd. all rights reserved. 4.dec.2013 rev.003 www.rohm.com tsz22111 ~ 15~ 001 physical dimension, tape and reel information (BD81A04AMUV-M) package name vqfn28sv5050
33/34 datasheet datasheet BD81A04AMUV-M bd81a04aefv-m tsz02201-0g3g0c600010-1-2 ? 2013 rohm co., ltd. all rights reserved. 4.dec.2013 rev.003 www.rohm.com tsz22111 ~ 15~ 001 physical dimension, tape and reel information (bd81a04aefv-m) package name htssop-b28 ? order quantity needs to be multiple of the minimum quantity. embossed carrier tape (with dry pack) 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 2500pcs e2 () direction of feed reel 1pin
34/34 datasheet datasheet BD81A04AMUV-M bd81a04aefv-m tsz02201-0g3g0c600010-1-2 ? 2013 rohm co., ltd. all rights reserved. 4.dec.2013 rev.003 www.rohm.com tsz22111 ~ 15~ 001 revision history date revision changes 22.oct.2013 002 new release. 4.dec.2013 003 p.1 a dd ?aec-q100 qualified?.
datasheet d a t a s h e e t notice - ss rev.002 ? 2014 rohm co., ltd. all rights reserved. notice precaution on using rohm products 1. if you intend to use our products in devices requiring extremely high reliability (such as medical equipment (note 1) , aircraft/spacecraft, nuclear power controllers, etc.) and whos e malfunction or failure may cause loss of human life, bodily injury or serious damage to property (?specific applications?), please consult with the rohm sales representative in advance. unless otherwise agreed in writ ing by rohm in advance, rohm shall not be in any way responsible or liable for any damages, expenses or losses in curred by you or third parties arising from the use of any rohm?s products for specific applications. (note1) medical equipment classification of the specific applications japan usa eu china class class class b class class class 2. rohm designs and manufactures its products subject to strict quality control system. however, semiconductor products can fail or malfunction at a certain rate. please be sure to implement, at your own responsibilities, adequate safety measures including but not limited to fail-safe desi gn against the physical injury, damage to any property, which a failure or malfunction of our products may cause. the following are examples of safety measures: [a] installation of protection circuits or other protective devices to improve system safety [b] installation of redundant circuits to reduce the impact of single or multiple circuit failure 3. our products are not designed under any special or extr aordinary environments or conditi ons, as exemplified below. accordingly, rohm shall not be in any way responsible or liable for any damages, expenses or losses arising from the use of any rohm?s products under an y special or extraordinary environments or conditions. if you intend to use our products under any special or extraordinary environments or conditions (as exemplified below), your independent verification and confirmation of product performance, reliability, etc, prior to use, must be necessary: [a] use of our products in any types of liquid, incl uding water, oils, chemicals, and organic solvents [b] use of our products outdoors or in places where the products are exposed to direct sunlight or dust [c] use of our products in places where the products ar e exposed to sea wind or corrosive gases, including cl 2 , h 2 s, nh 3 , so 2 , and no 2 [d] use of our products in places where the products are exposed to static electricity or electromagnetic waves [e] use of our products in proximity to heat-producing components, plastic cords, or other flammable items [f] sealing or coating our products with resin or other coating materials [g] use of our products without cleaning residue of flux (ev en if you use no-clean type fluxes, cleaning residue of flux is recommended); or washing our products by using water or water-soluble cleaning agents for cleaning residue after soldering [h] use of the products in places subject to dew condensation 4. the products are not subjec t to radiation-proof design. 5. please verify and confirm characteristics of the final or mounted products in using the products. 6. in particular, if a transient load (a large amount of load applied in a short per iod of time, such as pulse. is applied, confirmation of performance characteristics after on-boar d mounting is strongly recomm ended. avoid applying power exceeding normal rated power; exceeding the power rating under steady-state loading c ondition may negatively affect product performance and reliability. 7. de-rate power dissipation (pd) depending on ambient temper ature (ta). when used in seal ed area, confirm the actual ambient temperature. 8. confirm that operation temperat ure is within the specified range descr ibed in the product specification. 9. rohm shall not be in any way responsible or liable for fa ilure induced under deviant condi tion from what is defined in this document. precaution for mounting / circuit board design 1. when a highly active halogenous (chlori ne, bromine, etc.) flux is used, the resi due of flux may negatively affect product performance and reliability. 2. in principle, the reflow soldering method must be used; if flow soldering met hod is preferred, please consult with the rohm representative in advance. for details, please refer to rohm mounting specification
datasheet d a t a s h e e t notice - ss rev.002 ? 2014 rohm co., ltd. all rights reserved. precautions regarding application examples and external circuits 1. if change is made to the constant of an external circuit, pl ease allow a sufficient margin c onsidering variations of the characteristics of the products and external components, including transient characteri stics, as well as static characteristics. 2. you agree that application notes, re ference designs, and associated data and in formation contained in this document are presented only as guidance for products use. theref ore, in case you use such information, you are solely responsible for it and you must exercise your own independent verification and judgment in the use of such information contained in this document. rohm shall not be in any way responsible or liable for any damages, expenses or losses incurred by you or third parties arising from the use of such information. precaution for electrostatic this product is electrostatic sensitive product, which may be damaged due to electrostatic discharge. please take proper caution in your manufacturing process and storage so that voltage exceeding t he products maximum rating will not be applied to products. please take special care under dry condit ion (e.g. grounding of human body / equipment / solder iron, isolation from charged objects, se tting of ionizer, friction prevention and temperature / humidity control). precaution for storage / transportation 1. product performance and soldered connections may deteriora te if the products are stor ed in the places where: [a] the products are exposed to sea winds or corros ive gases, including cl2, h2s, nh3, so2, and no2 [b] the temperature or humidity exceeds those recommended by rohm [c] the products are exposed to di rect sunshine or condensation [d] the products are exposed to high electrostatic 2. even under rohm recommended storage c ondition, solderability of products out of recommended storage time period may be degraded. it is strongly recommended to confirm sol derability before using products of which storage time is exceeding the recommended storage time period. 3. store / transport cartons in the co rrect direction, which is indicated on a carton with a symbol. otherwise bent leads may occur due to excessive stress applied when dropping of a carton. 4. use products within the specified time after opening a hum idity barrier bag. baking is required before using products of which storage time is exceeding the recommended storage time period. precaution for product label qr code printed on rohm products label is for rohm?s internal use only. precaution for disposition when disposing products please dispose them proper ly using an authorized industry waste company. precaution for foreign exchange and foreign trade act since our products might fall under cont rolled goods prescribed by the applicable foreign exchange and foreign trade act, please consult with rohm representative in case of export. precaution regarding intellectual property rights 1. all information and data including but not limited to application example contain ed in this document is for reference only. rohm does not warrant that foregoi ng information or data will not infringe any intellectual property rights or any other rights of any third party regarding such information or data. rohm shall not be in any way responsible or liable for infringement of any intellectual property rights or ot her damages arising from use of such information or data.: 2. no license, expressly or implied, is granted hereby under any intellectual property rights or other rights of rohm or any third parties with respect to the information contained in this document. other precaution 1. this document may not be reprinted or reproduced, in whol e or in part, without prior written consent of rohm. 2. the products may not be disassembled, converted, modified, reproduced or otherwise changed without prior written consent of rohm. 3. in no event shall you use in any wa y whatsoever the products and the related technical information contained in the products or this document for any military purposes, incl uding but not limited to, the development of mass-destruction weapons. 4. the proper names of companies or products described in this document are trademarks or registered trademarks of rohm, its affiliated companies or third parties.
datasheet datasheet notice ? we rev.001 ? 2014 rohm co., ltd. all rights reserved. general precaution 1. before you use our pro ducts, you are requested to care fully read this document and fully understand its contents. rohm shall n ot be in an y way responsible or liabl e for fa ilure, malfunction or acci dent arising from the use of a ny rohms products against warning, caution or note contained in this document. 2. all information contained in this docume nt is current as of the issuing date and subj ec t to change without any prior notice. before purchasing or using rohms products, please confirm the la test information with a rohm sale s representative. 3. the information contained in this doc ument is provi ded on an as is basis and rohm does not warrant that all information contained in this document is accurate an d/or error-free. rohm shall not be in an y way responsible or liable for an y damages, expenses or losses incurred b y you or third parties resulting from inaccur acy or errors of or concerning such information.

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