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1/17 www.rohm.com 2009.07 - rev.b ? 2009 rohm co., ltd. all rights reserved. power supply ic series for tft-lcd panels ingle s -channel source voltage output power supply + gamma buffer amp ics bd8151efv,BD8157EFV description the bd8151efv,BD8157EFV power supply ic are designed for use with tft-lcd panels. it incorporates a built-in source voltage step-up switching regulator and gamma correction buf fer amp. the combination of a source power supply and gamma correction buffer on a single chip delivers significant cost savings. compatible with input voltages from 2.5 v to 5.5 v (bd8151e fv), 2.1 v to 4.0 v (BD8157EFV), the ic supports low-voltage operation and reaches over 85% efficiency with a 2.5 v in put, contributing to low power consumption designs. features 1) single-chip implementation of a source power supply and gamma correction buffer 2) support for low-voltage operation, with inpu t voltages from 2.5 v to 5.5 v (bd8151efv) 2.1 v to 4.0 v (BD8157EFV) 3) built-in 1.4 a, 0.2 ? low-voltage fet 4) switchable step-up dc/dc swit ching frequencies: 600 khz/1.2 mhz 5) current mode pwm control 6) under-voltage lockout protection circuit 7) built-in overcurrent protection circuit 8) built-in thermal shutdown circuit applications satellite navigation systems, laptop pc tft lcd panels lcd monitor panels absolute maximum ratings (ta = 25 ) parameter symbol limit unit power supply voltage vcc 7 v power dissipation pd 1000* mw operating temperature range bd8151efv topr ? 40 to +85 BD8157EFV ? 40 to +125 storage temperature range tstg ? 55 to +150 switching pin current isw 1.5** a switching pin voltage vsw 15 v vs voltage vs 15 v maximum junction temperature tjmax 150 c * reduced by 8 mw/ over 25 , when mounted on a glass epoxy board (70 mm x 70 mm x 1.6 mm). ** must not exceed pd. recommended operating ranges (ta = 25 ) parameter symbol limit unit min. typ. max. power supply voltage bd8151efv vcc 2.5 3.3 5.5 v power supply voltage BD8157EFV vcc 2.1 2.5 4.0 v switching current isw 1.4 a switching pin voltage vsw 14 v vs pin voltage vs 5 9 14 v no.09035ebt11 downloaded from: http:///
bd8151efv, BD8157EFV technical note 2/17 www.rohm.com 2009.07 - rev.b ? 2009 rohm co., ltd. all rights reserved. electrical characteristics bd8151efv (unless otherwise specified, ta = 25 ; vcc = 3.3v, enb = 3.3v) parameter symbol limit unit conditions min. typ. max. [triangular waveform oscillator] oscillating frequency 1 fosc1 540 600 660 khz fclk = 0 v oscillating frequency 2 fosc2 1.08 1.20 1.32 mhz fclk = vcc [overcurrent protection circuit] overcurrent limit isw 2 a [soft start circuit] ss source current iso 6 10 14 a vss = 0.5 v [under-voltage lockout protection circuit] off threshold voltage vutoff 2.1 2.2 2.3 v on threshold voltage vuton 2.0 2.1 2.2 v [error amp] input bias current ib 0.1 0.5 a feedback voltage vfb 1.232 1.245 1.258 v buffer [output] on resistance ron 200 300 m ? *isw = 1 a max. duty ratio dmax 72 80 88 % rl = 100 ? [enb] enb on voltage von vcc 0.7 vcc v enb off voltage voff 0 vcc 0.3 v [overall] standby current istb 0 10 a venb = 0 v average consumption current i cc 1.2 2.4 ma no switching [amp] input bias current ibo ? 1 0 1 a in += 4.5 v drive current 1 ioo1 50 70 140 ma out1 to out4 drive current 2 ioo2 150 200 400 ma vcom max. output current voho vs-0.16 vs-0.1 v io = ? 5 ma, in += vs min. output current vohl 0.1 0.16 v io = 5 ma, in += 0 v ? this product is not designed for protection against radio active rays. * design guarantee (no total shipment inspection is made.) downloaded from: http:///
bd8151efv, BD8157EFV technical note 3/17 www.rohm.com 2009.07 - rev.b ? 2009 rohm co., ltd. all rights reserved. electrical characteristics BD8157EFV (unless otherwise specified, ta = 25 ; vcc = 2.5v, enb = 2.5v) parameter symbol limit unit conditions min. typ. max. [triangular waveform oscillator] oscillating frequency 1 fosc1 480 600 720 khz fclk = 0 v oscillating frequency 2 fosc2 0.96 1.20 1.44 mhz fclk = vcc [overcurrent protection circuit] overcurrent limit isw 2 a [soft start circuit] ss source current iso 6 10 14 a vss = 0.5 v [under-voltage lockout protection circuit] off threshold voltage vutoff 1.7 1.8 1.9 v on threshold voltage vuton 1.6 1.7 1.8 v [error amp] input bias current ib 0.1 0.5 a feedback voltage vfb 1.232 1.245 1.258 v buffer [output] on resistance ron 200 600 m ? *isw = 1 a max. duty ratio dmax 75 85 95 % rl = 100 ? [enb] enb on voltage von vcc 0.7 vcc v enb off voltage voff 0 vcc 0.3 v [overall] standby current istb 0 10 a venb = 0 v average consumption current i cc 1.2 2.4 ma no switching [amp] input bias current ibo ? 1 0 1 a in += 4.5 v drive current 1 ioo1 50 70 140 ma out1 to out4 drive current 2 ioo2 120 200 400 ma vcom max. output current voho vs-0.16 vs-0.1 v io = ? 5 ma, in += vs min. output current vohl 0.1 0.16 v io = 5 ma, in += 0 v ? this product is not designed for protection against radio active rays. * design guarantee (no total shipment inspection is made.) downloaded from: http:///
bd8151efv, BD8157EFV technical note 4/17 www.rohm.com 2009.07 - rev.b ? 2009 rohm co., ltd. all rights reserved. reference data (unless otherwise specified, ta = 25 ) fig. 7 fclk pin current fig. 8 enb pin current fig. 9 comp sinking vs source current 0 5 10 15 20 0.0 0.5 1.0 1.5 2.0 2.5 3.0 enb voltage : venb[v] enb current : enb[ a] . -100 -50 0 50 100 1.0 1.1 1.2 1.3 1.4 1.5 comp voltage : vcomp[v] comp current : icomp[ua] . -40 0 5 10 15 20 0.0 0.5 1.0 1.5 2.0 2.5 3.0 fclk voltage : fclk[v] fclk current : fclk[ a] . 125 25 -40 125 25 fig. 5 reference voltage temperature fig. 6 switching frequency temperature 0 500 1000 1500 2000 - 40 -15 10 35 60 85 110 ambient temperature : ta[ ] switching frequency : fsw[khz] fig. 4 ss source current -20 -16 -12 -8 -4 0 00 . 5 11 . 52 ss voltage : vss[v] ss current : iss[ a] 2 .4 vfclk=vcc 0.0 0.5 1.0 1.5 2.0 0 1.5 3 4.5 6 7.5 supply voltage : vcc[v] reference voltage : vref[v] vfclk=gnd fig. 10 max. duty ratio temperature fig. 11 vcc = 2.5 v power efficiency fig. 12 vcc = 3.3 v power efficiency 50 60 70 80 90 100 0 0.05 0.1 0.15 0.2 0.25 0.3 output current : io[a] efficiency [%] 50 60 70 80 90 100 0 0.15 0.3 0.45 0.6 output current : io[a] efficiency [%] 0.02 vcc=3.3v f=600khz vcc=3.3v f=1200khz vcc=2.5v f=1200khz vcc=2.5v f=600khz 80 85 90 95 100 - 40 0 40 80 120 ambient temperature : ta[ ] max duty [%] 125 BD8157EFV bd 8157efv bd8151efv 0.00 0.25 0.50 0.75 1.00 1.25 1.50 1.75 0123456 supply voltage : vcc[v] supply current: icc[ma] . 0.5 1.230 1.235 1.240 1.245 1.250 1.255 1.260 -40 -15 10 35 60 85 110 ambient temperature : ta[ ] reference voltage : vref[v] . -2.0 -1.5 -1.0 -0.5 0.0 0.5 1.0 1.5 2.0 01234 supply voltage : vcc[v] standby current : icc[ a] . fig. 1 total supply current fig. 3 reference voltage temperature fig. 2 standby current 25 150 125 25 -40 -40 downloaded from: http:///
bd8151efv, BD8157EFV technical note 5/17 www.rohm.com 2009.07 - rev.b ? 2009 rohm co., ltd. all rights reserved. reference data (unless otherwise specified, ta = 25 ) fig. 13 power efficiency vs power supply voltage 50 60 70 80 90 100 2.0 2.5 3.0 3.5 4.0 supply voltage : vcc[v] efficiency [%] BD8157EFV BD8157EFV fig. 14 max. load current vs power supply voltage 8 8.2 8.4 8.6 8.8 9 0.0 0.1 1.0 load current : io[a] output voltage : vo[v] fig. 16 ss capacitance vs delay time fig. 17 vs pin current fig. 18 output voltage load regulation 1 0 2 4 6 8 10 0 5 10 15 vs voltage : vs[v] vs current : is[ma] 0.01 0.1 1 10 0.001 0.01 0.1 ss capacitance [ f] delay time [ms] fig. 19 buffer voltage fig. 20 buffer sinking current fig. 21 buffer source current -20 -15 -10 -5 0 5 10 123456789 buffer input voltage:vin[v] offset voltage:voffset[m v 0 1 2 3 4 5 6 7 8 9 0 25 50 75 100 125 150 175 200 output current : iout[ma] . output voltage : vout[v] 0 1 2 3 4 5 6 7 8 9 -200 -175 - 150 - 125 - 100 -75 -50 - 25 0 output current : iout[ma] . output voltage : vout[v] -40 25 125 -40 25 125 0 0.2 0.4 0.6 0.8 2.1 2.4 2.7 3.0 3.3 3.6 3.9 supply voltage : vcc[v] maximum current : iomax[a] . fig. 15 load response waveform io=0ma vo io=100ma 100mv/div 20us/div f=600khz f=1200khz fig. 22 vcom sinking current fig. 23 vcom source current 0 1 2 3 4 5 6 7 8 9 0 50 100 150 200 250 300 output current : iout[ma] . output voltage : vout[v] . 0 1 2 3 4 5 6 7 8 9 -300 -250 - 200 -150 -100 -50 0 output current : iout[ma] output voltage : vout[v] . -40 25 125 -40 25 125 fig. 24 slew rate waveform in out 1us/div 2v/div downloaded from: http:///
bd8151efv, BD8157EFV technical note 6/17 www.rohm.com 2009.07 - rev.b ? 2009 rohm co., ltd. all rights reserved. pin assignment diagram block diagram pin assignment diagram and pin functions pin no. pin name function 1 sw n-channel power fet drain output 2 vcc power supply input pin 3 enb control input pin 4 fclk frequency switching pin 5 vs buffer power supply input pin 6 comin vcom input pin 7 in1 amp input pin 1 8 in2 amp input pin 2 9 in3 amp input pin 3 10 in4 amp input pin 4 11 out4 amp output pin 4 12 out3 amp output pin 3 13 out2 amp output pin 2 14 out1 amp output pin 1 15 vcom vcom output pin 16 ss soft start current output pin 17 comp error amp output pin 18 fb error amp inversion input pins 19 gnd ground pin 20 pgnd ground pin fig. 25 pin assignment diagram and block diagram sw vcc enb fclk vs comin in1 in2 in3 in4 pgnd gnd fb comp ss vcom out1 out2 out3 out4 comin 13 12 11 6 7 8 9 10 2 3 4 5 1 slope osc uvlo tsd + set reset sdwn logic current sense + - err 20 19 18 16 15 14 17 buffer supply 1.245v sw vcc enb fclk vs in1 in2 in3 in4 pgnd gnd fb comp ss vcom out1 out2 out3 out4 pwm + - ocp drv start soft top view downloaded from: http:///
bd8151efv, BD8157EFV technical note 7/17 www.rohm.com 2009.07 - rev.b ? 2009 rohm co., ltd. all rights reserved. description of operation of each block ? error amp (err) this is the circuit to compare the reference voltage 1.24 5 v (typ.) and the feedback volt age of output voltage. the com pin voltage resulting from this comparison determines the switch ing duty. at the time of start, since the soft start is operated by the ss pin voltage, the comp pin voltage is limited to the ss pin voltage. ? oscillator (osc) this block generates the oscillating fr equency. either a 600 khz or 1.2 mhz (typ.) frequency can be selected with the fclk pin. ? slope this block generates the triangular waveform from the clo ck generated by osc. generated triangular waveform is sent to the pwm comparator. ? pwm the comp pin voltage output by the error amp is compared to the slope block's triangul ar waveform to determine the switching duty. since the switching duty is limited by the maximum duty ratio which is decided internally, it does not become 100%. ? reference voltage (vref) this block generates the internal reference voltage of 1.245 v (typ.). ? protection circuit (uvlo/tsd) uvlo (under-voltage lockout protection circuit) shuts down the circuits when the voltages are 2.2 v (typ.bd8151efv) 1.8 v (typ.nd8157efv) or lower. thermal shutdown circuit shuts down ic at 175c (typ.) and recovers at 160c (typ.). ? overcurrent protection circuit (ocp) current flowing to the power fet is detected by volta ge at the current sense and the ov ercurrent protection operates at 3 a (typ.). when the overcurrent prot ection operates, switching is turned off and the ss pin capacity is discharged. ? soft start circuit since the output voltage rises gradually while restricting the curr ent at the time of startup, it is possible to prevent the output voltage overshoot or the inrush current. ? buffer amp and vcom this buffer amp is used to set the gamma correction voltage, wh ich can be set in from 0.2 v to (vout - 0.2 v). use the vout resistance division to set the gamma correctio n voltage. the vcom voltage is set similarly. fig. 26 application circuit diagram 10uf vo rb161m-20 vcom v1v2 v3 v4 10uh 10uf vcc 2.5v comin 13 12 11 6 7 8 9 10 2 3 4 5 1 slope osc uvlo tsd + set reset sdwn logic current sense + - err 20 19 18 16 15 14 17 buffer supply 1.245v sw vcc enb fclk vs in1 in2 in3 in4 pgnd gnd fb comp ss vcom out1 out2 out3 out4 pwm + - ocp drv start soft top view 20k 20k 20k 20k 20k 20k 20k 100k 15k 5.1k 3300pf 0.01uf downloaded from: http:///
bd8151efv, BD8157EFV technical note 8/17 www.rohm.com 2009.07 - rev.b ? 2009 rohm co., ltd. all rights reserved. timing chart startup sequence overcurrent protection operating vcc enb ss sw vo io 2.5v vcc,enb ss sw vo fig. 27 startup sequence fig. 28 overcurrent protection operating downloaded from: http:///
bd8151efv, BD8157EFV technical note 9/17 www.rohm.com 2009.07 - rev.b ? 2009 rohm co., ltd. all rights reserved. selecting application components (1) setting the output l constant the coil l to use for output is decided by the rating current i lr and input current maximum value i inmax of the coil. adjust so that i inmax + ? i l does not reach the rating current value i lr . at this time, ? i l can be obtained by the following equation. ? i l = 1 vcc ? vo-vcc ? 1 [a] where, f is the switching frequency. l vcc f set with sufficient margin because the coil l value may have the dispersion of approx. ? 30%. if the coil current exceeds the rating current i lr of the coil, it may damage the ic internal element. BD8157EFV uses the current mode dc/dc converter control and has the optimized de sign at the coil value. the following coil values are recommended from the aspects of power effici ency, response and safety. when the coil out of this range is selected, the stable continual operation is not guaranteed such as the switching waveform becomes irregular. please pay attention to it. switching frequency: l = 10 h to 22 h at 600 khz switching frequency: l = 4.7 h to 15 h at 1,200 khz (2) setting the output capacitor for the capacitor c to use for the output, select the capacitor which has the larger val ue in the ripple voltage v pp allowance value and the drop voltage allowance valu e at the time of sudden load change. output ripple voltage is decided by the following equation. ? v pp = i lmax r esr + 1 ? vcc ? (i lmax - ? i l ) [v] where, f is the switching frequency. fco vo 2 perform setting so that the voltage is within the allowable ripple voltage range. for the drop voltage during sudden load change; v dr , please perform the rough calculation by the following equation. vdr = ? i ? 10 sec [v] co however, 10 s is the rough calculation value of the dc/dc response speed. pleas e set the capacitance considering the sufficient margin so that these two va lues are within the standard value range. (3) selecting the input capacitor since the peak current flows between the input and output at t he dc/dc converter, a capacitor is required to install at the input side. for this reason, the low esr capacitor is recommended as an input ca pacitor which has the value more than 10 f and less than 100 m ? . if a capacitor out of this range is selected, t he excessive ripple voltage is superposed on the input voltage, accordingly it may cause the malfunction of ic. however these conditions may vary according to the load current, input voltage, output voltage, inductance and switching frequency. be sure to perform the margin check using the actual product. il t i inmax + ? i l should not reach the rating value level i inmax average current fig. 29 coil current waveform fig. 30 output applic ation circuit diagram l vcc i l vo co downloaded from: http:///
bd8151efv, BD8157EFV technical note 10/17 www.rohm.com 2009.07 - rev.b ? 2009 rohm co., ltd. all rights reserved. (4) selecting the output rectification diode schottky barrier diode is recommended as the rectification di ode to use at the dc/dc conver ter output stage. select the diode paying attention to the max. in ductor current and max. output voltage. max. inductor current i inmax + ? i l < rating current of diode max. output voltage v omax < rating voltage of diode since each parameter has 30% to 40% of dispersion, be sure to design providing sufficient margins. (5) design of the feedback resistor constant refer to the following equation to set t he feedback resistor. as the setting range, 10 k ? to 330 k ? is recommended. if the resistor is set to a 10 k ? or lower, it causes the reduction of power efficiency. if it is set to 330 k ? or larger, the offset voltage becomes larger by the input bias current 0.4 a (typ.) in the internal error amplifier. step-up vo = r8 + r9 ? 1.245 [v] r9 (6) setting the soft start time soft start is required to prevent the coil curre nt at the time of startup from increasing and the overshoot of the out put voltage at the starting time. fig. 32 shows the relation between the capacitance and soft st art time. please refer to it to set the capacitance. as the capacitance, 0.001 f to 0.1f is recommended. if the capacitance is set to 0.001 f, the overshooting may occur on the output voltage. if the capacitance is set to 0.1 f or larger, the excessive back current flow may occur in the internal parasitic elements when the power is turned off and it may damage ic. when the capacitor of 0.1 f or larger is used, be su re to insert a diode to vcc in series, or a bypass diode between the ss pin and vcc. fig. 33 bypass diode example when there is the startup relation (sequences) with other power su pplies, be sure to use the high accuracy product (such as x5r ). soft start time may vary according to the input voltage, outpu t voltage loads, coils and output capacity. be sure to verify the operation using the actual product. (7) setting the enb pin when the enb pin is set to hi, the internal circuit becomes active and the dc/dc converter starts operating. when it is set to low, the shut down is activated and all circuits will be turned off. (8) setting the frequency by fclk it is possible to change the switching frequency by setting the fclk pin to hi or low. when it is set to low, the product operates at 600 khz (typ.). when it is set to hi, the product operates at 1,200 khz (typ.). 0.01 0.1 1 10 0.001 0.01 0.1 ss capacitance[uf] delay time[ms] fig. 31feedback resistance setting fig.32 ss pin capacitance vs delay time vcc output pin back current prevention diode bypass diode vo r8 r9 err reference voltage 1.245 v fb 2 downloaded from: http:///
bd8151efv, BD8157EFV technical note 11/17 www.rohm.com 2009.07 - rev.b ? 2009 rohm co., ltd. all rights reserved. (9) setting r c , c c of the phase compensation circuit in the current mode control, since the coil current is controlled, a pole (phase lag) made by the cr filter composed of the output capacitor and load resistor will be created in the low frequency range, and a zero (phase lead) by the output capacitor and esr of capacitor will be created in the high frequenc y range. in this case, to cancel the pole of the power amplifier, it is easy to compensate by adding the zero point with c c and r c to the output from the error amplifier as shown in the illustration. open loop gain pole at the power amplification stage when the output current redu ces, the load resistance r o increases and the pole frequency lowers. error amplifier phase compensation zero at the power amplification stage when the output capacitor is set larger, the pole frequency lowers but the zero frequency will not change. (this is because the capacitor esr becomes 1/2 when the capacitor becomes 2 times.) it is possible to realize the stable feedback loop by canceling the pole fp (min.), which is created by the output capacitor and load resistor, with cr zero compensation of the error amplifier as shown below. fz (amp.) = fp (min.) 1 = 1 2 ? ? rc ? cc 2 ? ? romax ? co as the setting range for the resistor, 1 k ? to 10 k ? is recommended. when the resistor is set to 1 k ? or lower, the effect by phase compensation becomes low and it may cause the os cillation of output voltage. when it is set to 10 k ? or larger, the comp pin becomes hi-z and the switching noise becomes easy to superpose. therefore the stable switching pulse cannot be generated and the irregular ripple voltage may be generated on the output voltage. as the setting range for the capacitance, 3,300 pf to 10,000 pf is recommended. when the capacitance is set to 3,300 pf or lower, the irregular ripple voltage may be generated on the outpu t voltage due to the effect of switching noise. when it is set to 10,000 pf or larger, the response becomes worse and the output voltage fluctuation bec omes large. accordingly it may require the output capacitor which is larger than the necessary value. 1 fp = 2 ? ? ro ? co 1 fz (esr) = 2 ? ? e sr ? co 1 fp(min) = 2 ? ? ro max ? co [hz] (at light-load) fz(max) = 1 [hz] (at heavy-load) fp(min) fp(max) fz(esr) a 0 -90 0 gain db phase deg l out min l out max 0 0 a -90 gain db phase deg fig. 34 gain vs phase fig. 35 application circuit diagram [hz] [hz] [hz] v cc rc cc cin vcc,pvcc gnd,pgnd sw comp co esr ro vo l 2 ? ? ro min ? co 1 fp (amp.) = 2 ? ? rc ? cc [hz] downloaded from: http:///
bd8151efv, BD8157EFV technical note 12/17 www.rohm.com 2009.07 - rev.b ? 2009 rohm co., ltd. all rights reserved. (10) using the buffer amp and vcom the 4-channel buffer amp and 1-channel vcom output are used to generate the gamma compensation voltage that is input to the source driver. the vs pin serves as the power supply for the buffer amp and vcom. use caution as the gamma co rrection buffer amp and vcom have differen t output current capacities. a range from i/o power supply to ground potentials can be set for the built-in buffer amplifier. if output voltage noise becomes problematic, insert a 0.1 f capacitor in the output ci rcuit. a capacitance value of 0 pf to 1 f is recommended for this capacitor. large capacitance values of 1 f or larger may cause back current to flow through intern al parasitic diodes in the event of a supply voltage ground fault, causing damage to internal ic elements. for applications wher e such modes are anticipated, implement a bypass diode or other preventive measure. vs v1 v2 v3 v4 vs vcom voltage output v1 v2 v3 v4 for gamma correction gamma correction voltage output v comin v in 1 v in 2 v in 3 v in 4 fig. 36 example buffer amp circuit fig. 37 gamma correction voltage startup waveform wait for trigge r downloaded from: http:///
bd8151efv, BD8157EFV technical note 13/17 www.rohm.com 2009.07 - rev.b ? 2009 rohm co., ltd. all rights reserved. application examples * although rohm is sure that the applic ation examples are recommendable ones, further check the characteristics of components that require high precision befor e using them.when a circuit is used modifying the externally connected circuit constant, be sure to decide allowing sufficient margins considering the dispersion of values by external parts as well as our ic including not only the static but also the transient characteristic. for the patent, we have not acquired the suffici ent confirmation. please acknowledge the status. (1) when the charge pump is removed from the dc/dc converter to make it 3-channel output mode: it is possible to create the charge pump by using the switching operation of dc/ dc converter. when the application shown in the following diagram is used, 1- channel dc/dc converter output, 1-channel positive side charge pump and 1-channel negative side charge pump can be output as a total of 3 channels. (2) when the output voltage is set to 0 v: since the switch does not exist between the input and output in the application using the step-up type dc/dc converter, the output voltage is generated even if the ic is turned of f. when it is intended to keep the output voltage 0 v until ic operates, insert the switch as shown in the following circuit diagram. fig. 38 3 ch application circuit diagram example fig. 39 switch applicatio n circuit diagram example 10uf vout rb161m-20 vcom v1v2 v3 v4 10uh 10uf vcc 2.5v comin 13 12 11 6 7 8 9 10 2 3 4 5 1 slope osc uvlo tsd + set reset sdwn logic current sense + - err 20 19 18 16 15 14 17 buffer supply 1.245v sw vcc enb fclk vs in1 in2 in3 in4 pgnd gnd fb comp ss vcom out1 out2 out3 out4 pwm + - ocp drv start soft top view 0.1uf 0.1uf 1uf 1uf 0.1uf 1uf 1uf vgh 1uf vgl dan217u 2sd2657k dan217u 2sb1695k udz series udz series 10uf vo rb161m-20 vcom v1 v2 v3 v4 10uh 10uf vcc 2.5v comin 13 12 11 6 7 8 9 10 2 3 4 5 1 slope osc uvlo tsd + set reset sdw n logic current sense + - err 20 19 18 16 15 14 17 buffer supply 1.245v sw vcc enb fclk vs in1 in2 in3 in4 pgnd gnd fb comp ss vcom out1 out2 out3 out4 pw m + - ocp drv start soft top view downloaded from: http:///
bd8151efv, BD8157EFV technical note 14/17 www.rohm.com 2009.07 - rev.b ? 2009 rohm co., ltd. all rights reserved. i/o equivalent circuit diagrams 1.sw 11.out4 12.out3 13.out2 14.out1 15.vcom 3.enb 4.fclk 16.ss 6.comin 7.in1 8.in2 9.in3 10.in4 17.comp 18.fb fig.40 i/o equivalent circuit diagrams vcc 200k ? vs vs vcc vcc downloaded from: http:///
bd8151efv, BD8157EFV technical note 15/17 www.rohm.com 2009.07 - rev.b ? 2009 rohm co., ltd. all rights reserved. notes for use 1) absolute maximum ratings use of the ic in excess of absolute maximum ratings such as the applied voltage or op erating temperature range may result in ic damage. assumptions should not be made regardin g the state of the ic (short mode or open mode) when such damage is suffered. a physical safety measure such as a fuse should be implemented when use of the ic in a special mode where the absolute maximum ratings may be exceeded is anticipated. 2) gnd potential ensure a minimum gnd pin potentia l in all operating conditions. 3) setting of heat use a thermal design that allows for a suffic ient margin in light of the power dissipa tion (pd) in actual operating conditions. 4) pin short and mistake fitting use caution when orienting and positioning the ic for mounting on an application board. 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 the presence of a foreign object may result in damage to the ic. 5) actions in strong magnetic field use caution when using the ic in the pres ence of a strong magnetic field as doi ng so may cause the ic to malfunction. 6) testing on application boards when testing the ic on an application boar d, connecting a capacitor to a pin with low impedance subjects the ic to stress. always discharge capacitors after each process or step. ground the ic during assembly steps as an antistatic measure, and use similar caution when transporting or st oring the ic. always turn the ic's power supply off before connecting it to or removing it from a jig or fixtur e during the inspection process. 7) ground wiring patterns when using both small signal and large current gnd pattern s, it is recommended to isolate the two ground patterns, placing a single ground point at the application's referenc e point so that the pattern wiring resistance and voltage variations caused by large currents do not cause variations in the small signal ground voltage. be careful not to change the gnd wiring patterns of any external components. 8) this monolithic ic contains p+ isolat ion and p substrate layers between adjacent el ements in order to keep them isolated. p/n junctions are formed at the intersection of these p layers with the n layers of other elements to create a variety of parasitic elements. for example, when the resistors and transistors are connected to the pi ns as shown in fig. 41, a parasitic diode or a transistor operates by inversing the pin voltage and gnd voltage. the formation of parasitic elements as a result of the relationshi ps of the potentials of different pins is an inevitable resul t of the ic's architecture. the operation of parasitic elements can cause interference with circuit operation as well as ic malfunction and damage. for these reasons, it is necessary to use caution so that the ic is not used in a way that will trigger the operation of parasitic elements, such as the applic ation of voltages lower than the gnd (p substrate) voltage to input and output pins. 9) overcurrent protection circuits an overcurrent protection circuit designed according to t he output current is incorpor ated for the prevention of ic destruction that may result in the event of load shorting. this protection circuit is effective in preventing damage due to sudden and unexpected accidents. however, the ic should not be used in applications characterized by the continuous operation or transitioning of the protection circuits. at the time of thermal des igning, keep in mind that the current capacity has negative characteristics to temperatures. 10) thermal shutdown circuit (tsd) this ic incorporates a built-in tsd circuit for the protecti on from thermal destruction. t he ic should be used within the specified power dissipation range. however, in the event that the ic continues to be oper ated in excess of its power dissipation limits, the attendant rise in the chip's temperature tj will trigger the temperature protection circuit to turn off all output p o wer elements. the circuit automatically resets once the chip's temperature tj drops. operation of the tsd circuit presumes t hat the ic's absolute maximum ratings ha ve been exceeded. application designs should never make use of the tsd circuit. 11) testing on application boards at the time of inspection of t he installation boards, when the capacitor is c onnected to the pin with low impedance, be sure to discharge electricity per process because it may load stresses to the ic. always turn the ic's power supply off before connecting it to or removing it from a jig or fixture during the inspection proce ss. ground the ic during assembly steps as an antistatic measure, and use similar cautio n when transporting or storing the ic. fig.41 example of a simple monolithic ic architecture parasitic elements (pin b) gnd c b e (pin a) gnd n p n n p p resistor parasitic element p parasitic element gnd (pin a) gnd n p n n p p parasitic elements p substrate (pin b) c b e transistor (npn) n gnd downloaded from: http:///
bd8151efv, BD8157EFV technical note 16/17 www.rohm.com 2009.07 - rev.b ? 2009 rohm co., ltd. all rights reserved. ambient mperature :ta[ ] 0 25 50 75 100 125 2000 500 1500 1000 150 on 70701.6mm board powre dissipation : 1000 bd8151ef bd8157ef 85 power dissipation reduction fig.42 power dissipation reduction downloaded from: http:///
bd8151efv, BD8157EFV technical note 17/17 www.rohm.com 2009.07 - rev.b ? 2009 rohm co., ltd. all rights reserved. ordering part number b d 8 1 5 1 e f v - e 2 part no. part no. 8151 8157 package efv : htssop-b20 packaging and forming specification e2: embossed tape and reel (unit : mm) htssop-b20 s 0.08 s 11 20 11 0 (max 6.85 include burr) 6.5 0.1 (2.4) 4.4 0.1 0.325 6.4 0.2 (4.0) 0.17 +0.05 - 0.03 1.0 0.2 0.5 0.15 0.65 0.08 0.05 0.85 0.05 1.0max 0.24 +0.05 - 0.04 ? order quantity needs to be multiple of the minimum quantity. embossed carrier tape (with dry pack) tapequantity 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 downloaded from: http:///
datasheet d a t a s h e e t notice - ge rev.002 ? 2014 rohm co., ltd. all rights reserved. notice precaution on using rohm products 1. our products are designed and manufac tured for application in ordinary elec tronic equipments (such as av equipment, oa equipment, telecommunication equipment, home electroni c appliances, amusement equipment, etc.). if you intend to use our products in devices requiring ex tremely high reliability (such as medical equipment (note 1) , transport equipment, traffic equipment, aircraft/spacecra ft, nuclear power controllers, fuel c ontrollers, car equipment including car accessories, safety devices, etc.) and whose malfunction or failure may cause loss of human life, bodily injury or serious damage to property (specific applications), please consult with the rohm sale s representative in advance. unless otherwise agreed in writing by rohm in advance, 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 any ro hms 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 designed and manufactured for use under standard conditions and not under any special or extraordinary environments or conditio ns, as exemplified below. accordin gly, rohm shall not be in any way responsible or liable for any damages, expenses or losses arising from the use of an y rohms products under any 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 described 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 downloaded from: http:///
datasheet d a t a s h e e t notice - ge 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 considering 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 humidity 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 rohms 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 contained 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. downloaded from: http:///
datasheet datasheet notice C 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. downloaded from: http:///

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