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1/20 www.rohm.com 2010.1 1 - rev . a ? 2010 rohm co., ltd. all rights reserved. regulators ics for digit a l cam e ras and camc orders switching regulator ic with built-in fet (5v) bd9757mw v desc ri ptio n BD9757MWV is an 8-channel switching regulator with a built-i n fet for digital still camera. it has a built-in function to light-control the white led for backlight according to the light control setting signal from microcomputer. f e atur es 1) starting from vbat terminal of 1.5v 2) power of internal circuit is supplied from voltage boost ch1 3) mounted with a total of 8ch including voltage boost 2ch, voltage step-down 4ch, inversion 1ch, and white led-purpose voltage boost (compatible with dc light control) 1ch 4) built-in 5-channel transistors for synchronous rectification 5) built-in 2-channel fet transistors for voltage boost 6) built-in all-channel phase compensation between input and output of error amplifier 7) channel 1 and 3 are common, but other chan nels are independent, so the on/off is possible 8) operating frequencies of 1.2m hz (ch1 ~ 5), 600khz(ch6 ~ 8) 9) built-in output breaking circuit (timer latch type) at the time of overload 10) built-in 2ch of high side switch with soft start function 11) uqfn044v6060 package (6mm 6mm ,0.4mm pitch) with heat dissipation a p p lic ati o n s digital still camera a b s o lute maximum r a tings (ta=25 ) parameter symbol ratings units power supply voltage vbat -0.3 ~ 7 v power input voltage vhx1 ~ 5 -0.3 ~ 7 v hs78h -0.3 ~ 7 v vlx7,8 -0.3 ~ 22 v maximum output current iomaxlx1 2.5 a iomaxhx1 1.5 a iomaxhx2,5 +1.0 a iomaxhx3,4 +0.8 a iomaxhs78 +1.2 a iomaxlx7,8 1.0 a power dissipation pd 0.54 ( 1) w operating temperature range topr -25 ~ +85 storage temperature range tstg -55 ~ +150 junction temperature tjmax +150 1 at the time of a single ic. if used in more than ta=25 , reduced by 4.32mw/ . no.10036eat09 downloaded from: http:///
technical note 2/20 bd9757mw v www.rohm.com 2010.1 1 - rev . a ? 2010 rohm co., ltd. all rights reserved. o per ati ng c o n d i tio n s parameter symbol ratings unit conditions min. typ. max. power supply voltage vbat 1.5 - 5.5 v vref terminal connection capacity cvref 0.47 1.0 4.7 f vrega terminal connection capacity cvrega 0.47 1.0 4.7 f ch8 modulated light h fixed time when the modulated light control setting is determined t on 265x 1/fosc1 - - sec l fixed time when off t off 256x 1/fosc1 - - sec h fixed time at the time of modulated light control setting t h 500 - 10000 nsec l fixed time at the time of modulated light control setting t l 500 - 10000 nsec h fixed time at the time of en starting up t en 4x 1/fosc1 - - sec l fixed time before modulated light control setting t clr 7x 1/fosc1 - 255x 1/fosc1 sec time of light control setting at the time of starting up t set - - 2048x 1/fosc1 sec driver ch1 pmos drain current idpl1 - - 1.2 a ch1 nmos drain current idnl1 - - 2.3 a ch2,5 pmos drain current idpl2 - - 0.8 a ch2, 5 nmos drain current idnl2 - - 0.8 a ch3, 4 pmos drain current idpl22 - - 0.6 a ch3, 4 nmos drain current idnl22 - - 0.6 a ch6 driver output peak current idpeak - - 0.5 a ch7, 8 high side switch input current idpl7,8 - - 1.0 a ch7, 8 nmos drain current idnl6 - - 0.8 a output voltage setting range ch1 - 4.5 - 5.4 v ch2 - 1.0 - 4.4 v ch3 - 1.0 - 4.4 v ch4 - 1.0 - 4.4 v ch5 - 1.0 - 4.4 v ch6 - -8.0 - -5.0 v ch7 - 8.5 - 16 v ch8 - 8.5 - 20 v downloaded from: http:///
technical note 3/20 bd9757mw v www.rohm.com 2010.1 1 - rev . a ? 2010 rohm co., ltd. all rights reserved. e l ectr ic al c h a r act e rist ics ( unless specified, ta=25 , vccout=5.0v, vbat=3v, stb13 ~ 7=3v,upic8=2.5v) parameter symbol limits unit conditions min. typ. max. internal regulator vrega output voltage vrega 2.4 2.5 2.6 v io=5ma low-voltage input malfunction prevention circuit detecting voltage 1 vstd1 - 2.0 2.3 v vrega monitor hysteresis width 1 S vstd1 50 100 200 mv detecting voltage 2 vstd2 - 2.4 2.5 v vccout monitor hysteresis width 2 S vstd2 100 200 300 mv short-circuit protection circuit scp detecting time tscp 20 25 30 msec timer start threshold voltage vtcinv 0.38 0. 48 0.58 v inv terminal monitor ch3 ~ 5 start circuit oscillating frequency fstart 150 300 600 khz operation initiation vbat voltage vst1 1.5 - - v start-up ch soft start time tss1 1.8 3.0 5.3 msec oscillating circuit oscillating frequency ch1 ~ 5 fosc1 1.0 1.2 1.4 mhz oscillating frequency ch6 ~ 8 fosc2 0.5 0.6 0.7 mhz max duty 2,3,4,5(voltage step-down) dmax1d - - 100 % ( 2) max duty 1(voltage boost) dmax1u 86 92 96 % max duty 6,7,8 dmax2 86 92 96 % error amp input bias current iinv - 0 50 na inv1 ~ 8, non5=3.0v inv threshold 1 vinv1 0.79 0.80 0.81 v ch1 ~ 5 inv threshold 2 vinv2 0.99 1.00 1.01 v ch7,8v inv threshold 3 (max) vinv3 370 400 430 mv ch8i base bias voltage vref for inverted channel ch6 output voltage vout6 -6.09 -6.00 -5.91 v non6 12k ? , 72k ? ( 3) line regulation dvli - 4.0 12.5 mv vccout=1.5 ~ 5.5v output circuit at the time of shor t-circuit ios 0.2 1.0 - ma vref=0v soft start ch2, 5 soft start time tss2, 5 3.4 4.4 5.4 msec ch3, 4 soft start time tss3, 4 1.2 2.2 3.2 msec ch6 soft start time tss6 3.4 4.4 5.4 msec ch7, 8 soft start time tss7, 8 4.4 5.4 6.6 msec 2 the protective circuit start working when circuit is operated by 100% duty. so it is possible to use only for transition time shorter than charge time for scp. 3 recommend resistor value over 20k between vref to non6, because vref current is under 100a. this product is not designed for normal operation within a radioactive environment. downloaded from: http:///
technical note 4/20 bd9757mw v www.rohm.com 2010.1 1 - rev . a ? 2010 rohm co., ltd. all rights reserved. electrical characteristics (unless specified, ta=25 , vccout=5.0v, vbat=3v, stb13 ~ 7=3v,upic8=2.5v) parameter symbol limits unit conditions min. typ. max. output driver ch1 high side switch on resistance ron1p - 120 270 m ? hx1=5v ch1 low side switch on resistance ron1n - 80 240 m ? vccout=5.0v ch2 high side switch on resistance ron21p - 250 400 m ? hx2=5v ch2 low side switch on resistance ron21n - 250 400 m ? vccout=5.0v ch3 high side switch on resistance ron3p - 250 400 m ? hx3=3v , vccout=5v ch3 low side switch on resistance ron3n - 250 400 m ? vccout=5.0v ch4 high side switch on resistance ron4p - 250 400 m ? hx4=3v, vccout=5v ch4 low side switch on resistance ron4n - 250 400 m ? vccout=5.0v ch5 high side switch on resistance ron5p - 250 400 m ? hx5=5v ch5 low side switch on resistance ron5n - 150 300 m ? vccout=5.0v output voltage h at the time of ch6 driving vout6h vccout -1.5 vccout -1.0 - v iout6=50ma non6=0.2v output voltage l at the time of ch6 driving vout6l - 0.5 1.0 v iout6=-50ma, non6=-0.2v ch7,8 nmos switch on resi stance ron7,8n - 500 800 m ? vccout=5.0v ch7,8 load switch on resistance ron7,8p - 200 350 m ? hs7,8h=3v , vccout=5.0v stb1 ~ 7 stb control voltage operating vstbh1 1.5 - 5.5 v non-operating vstbl1 -0.3 - 0.3 v pull down resistance rstb1 250 400 700 k ? upic8 upic8 control voltage h level vupih 2.1 - 4.00 v l level vupil 0 - 0.40 v pull down resistance rupic1 30 50 80 k ? circuit current circuit current at the time of standby vbat terminal istb1 - - 5 a hs7,8h terminal istb4 - - 5 a hx terminal istb2 - - 5 a voltage step-down lx terminal istb3 - - 5 a voltage boost circuit current at the time of start-up (vbat terminal inflow current) ist - 150 450 a vbat=1.5v circuit current 1 at the time of operating (vbat terminal inflow current) icc1 - 45 150 a vbat=3.0v circuit current 2 at the time of operating (vccout applied terminal inflow current) icc2 - 5.0 9.7 ma inv1 ~ 8 = 1.2v , non6=-0.2v this product is not designed for normal operation within a radioactive environment. downloaded from: http:///
technical note 5/20 bd9757mw v www.rohm.com 2010.1 1 - rev . a ? 2010 rohm co., ltd. all rights reserved. ref e re nce data (1) fig.3 frequency ch6 ~ 8-temp fig.2 frequency ch1 ~ 5-temp fig.5 ch6 base voltage-temp fig.7 ch2 3.2v step-down efficiency-io fig.11 ch6 -6v inverting efficiency-io fig.1 start-up circuit frequency-temp fig.4 vrega output voltage-temp fig.6 ch1 5.0v voltage boost efficiency-io fig.8 ch2 3.2v step-down efficiency-io fig.9 ch4 1.8v step-down ef ficiency-io fig.10 ch5 3.5v step-down efficiency-io 0 100 200 300 400 500 600 -40 -20 0 20 40 60 80 100 ta [ ] freq[khz] start-up circuit operating frequency temperature characteristic 1.00 1.05 1.10 1.15 1.20 1.25 1.30 1.35 1.40 -40-20 0 20406080100 ta [ ] freq[mhz] current mode operating frequency temperature characteristic voltage mode operating frequency temperature characteristic 500 520 540 560 580 600 620 640 660 680 700 -40 -20 0 20 40 60 80 100 ta [ ] freq[khz] 2.40 2.42 2.44 2.46 2.48 2.50 2.52 2.54 2.56 2.58 2.60 -40 -20 0 20 40 60 80 100 ta [ ] vrega [v] vrega output voltage temperature characteristic 0.94 0.96 0.98 1.00 1.02 1.04 1.06 -40 -20 0 20 40 60 80 100 ta [ ] vref6 [v] vref6 output voltage temperature characteristic 60 65 70 75 80 85 90 95 100 10 100 1000 10000 load current[ma] efficiency vin=1.5v vin=2.4v vin=3.6v vin=4.2v ch1 boost 5.0 efficiency data 50 55 60 65 70 75 80 85 90 95 100 10 100 100 0 vin=.v vin=.v vin=.v vin=.v ch2 step-down 3.2v efficiency data efficiency load current[ma] 40 45 50 55 60 65 70 75 80 85 90 95 100 10 100 1000 vin=1.5v vin=2.4v vin=3.6v vin=4.2v vin=5.5v ch3 step-down 1.2v efficiency data load current [ma] efficiency 40 45 50 55 60 65 70 75 80 85 90 95 100 10 100 1000 vin=2.4v vin=3.6v vin=4.2v vin=5.5v ch4 step-down 1.8v efficiency data efficiency [%] load current [ma] vin=4.2v vin=4.8v vin=5.5v ch5 step-down 3.5v efficiency data efficiency [%] load current [ma] 40 50 60 70 80 90 100 11 01 0 0 vin=2.4v vin=3.6v vin=4.2v vin=5.5v ch6 reversal -6v efficiency data load current [ma] efficiency [%] downloaded from: http:///
technical note 6/20 bd9757mw v www.rohm.com 2010.1 1 - rev . a ? 2010 rohm co., ltd. all rights reserved. ref e re nce data (2) stb13 vo1 fig.14 ch1 start-up waveform (vbat=1.5v) fig.15 ch1,3 start-up waveform (vbat=3.0v) fig.16 ch2 start-up waveform inflow current(1a/div) stb13 vo1 vo3 inflow current (1a/div) stb2 vo2 inflow current (1a/div) fig.17 ch4 start-up waveform fig.18 ch5 start-up waveform fig.19 ch6 start-up waveform stb4 vo4 inflow current (1a/div) stb5 vo5 inflow current(1a/div) stb6 vo6 inflow current (1a/div) fig.20 ch7 start-up waveform fig.21 ch8 start-up waveform stb7 vo7 inflow current (1a/div) upic8 vo8 inflow current (1a/div) fig.12 ch7 12v boost efficiency-io fig.13 ch8 led boost efficiency-io 40 50 60 70 80 90 100 11 01 0 0 vin=1.5v vin=2.4v vin=3.6v vin=4.2v vin=5.5v ch7 boost12v efficiency data load current [ma] efficiency [%] 70 75 80 85 90 95 100 0123456 io=7.5ma io=12.5ma io=17ma io=20ma efficiency [v] input voltaage [v] ch8 led efficiency data downloaded from: http:///
technical note 7/20 bd9757mw v www.rohm.com 2010.1 1 - rev . a ? 2010 rohm co., ltd. all rights reserved. p i n ass i g n me nt fig.22 BD9757MWV top view p i n desc ri ptio n pin no. pin name i/o function notes 21 vbat i battery voltage input starting up at higher than 1.5v 28 vccout i power supply input terminal connecting the ch1 output 26 gnd - earth terminal 15,16,7,2,39 pgnd13,24,5, 678 - ea rth terminal with built-in fet 27 vrega o vrega output 2.5v output 30 vref6 o reference voltage output for ch6 inversion 1.0v output 41 out6 o ch6 pmos gate connection terminal 19,20,5,13,9,4 hx1,2,3,4,5 o synchronous rectification high side switch input terminal, pch driver power supply output 17,18,6,14,8,3,40,38 lx1,,2,3,4,5,7 ,8 o inductor connection terminal 36 hs78h i built-in load switch power supply input terminal 35,37 hs7l,hs8l o built-in load switch output terminal 22,25,23,24,29,32,34 inv1,2,3,4 ,5,7,8 i error amplifier inversion input terminal 31 non6 i error amplifier non-inversion input terminal 33 inv8i i error amplifier inversion input terminal 12,10,11,1,44,43 st b13,2,4,5,6,7 i ch1 ~ ch7 on / off switch operating :higher than 1.5v at the time of all low standby state 42 upic8 i ch8 start-up signal, led light control-purpose signal input 3435 36 37 38 3940 41 42 43 44 2221 20 1918 17 16 15 14 1312 12345678910 11 33 32 31 30 29 28 27 26 25 24 23 inv8 hs7l hs78h hs8l lx8 pgnd678 lx7 out6 upic8 stb7 stb6 vbat hx1 lx1 lx1 hx1 pgnd13 pgnd13 lx3 hx3 stb13 inv1 BD9757MWV stb5 pgnd5 lx5 hx5 hx2 lx2 pgnd24 lx4 hx4 stb2 stb4 inv3 inv4 inv2 gnd vccout vrega inv5 vref6 non6 inv7 inv8i downloaded from: http:///
technical note 8/20 bd9757mw v www.rohm.com 2010.1 1 - rev . a ? 2010 rohm co., ltd. all rights reserved. a p plic ation circuit (1) fig.23 applied circuit diagram 1(lithium 1 cell) operation notes ? we are confident that the above applied circuit diagram should be recommended, but please thoroughly confirm its characteristic s when using it. in addition, when using it with the external circuits constant changed, please make a decision that allows a sufficient margin in light of the fluctuations of external components and rohms ic in terms of not only st atic characteristic but also transient characteristic. downloaded from: http:///
technical note 9/20 bd9757mw v www.rohm.com 2010.1 1 - rev . a ? 2010 rohm co., ltd. all rights reserved. a p plic ation circuit (2) fig.24 applied circuit diagram 2(dry battery 2) operation notes ? we are confident that the above applied circuit diagram should be recommended, but please thoroughly confirm its characteristic s when using it. in addition, when using it with the external circuits constant changed, please make a decision that allows a sufficient margin in light of the fluctuations of external components and rohms ic in terms of not only st atic characteristic but also transient characteristic. downloaded from: http:///
technical note 10/20 bd9757mw v www.rohm.com 2010.1 1 - rev . a ? 2010 rohm co., ltd. all rights reserved. t i mi ng c h art ( 1 ) stb13, stb2 ch1 ch3 ch2 tss1 stb4, stb5 ch4 tss3 tss2 tss4 tss5 ch5 tss1 about 3.0msec tss3 about 2.2msec tss2 about 4.4msec tss4 about 2.2msec tss5 about 4.4msec after finished ch1 rise, other ch start rise. when ch1 is already risen, ch is start up with stb rise. fig.25 ch1 ~ 5 start-up sequence stb6, stb7 ch6 reverse output tss6 ch7 output tss7 tss6 about4.4msec tss7 about5.4msec fig.26 ch6, 7 start-up sequence downloaded from: http:///
technical note 11/20 bd9757mw v www.rohm.com 2010.1 1 - rev . a ? 2010 rohm co., ltd. all rights reserved. t i mi ng c h art ( 2 ) fig.27 ch8 start-up sequence upic8 led current a bout 5.4msec interval of soft start interval of modulated light setting led current is adjusted according to the set number of counts soft start is started according to setting vo8 it is returned immediately if the set voltage is exceeded tss8 tss8 oscillating frequency=6400counts about 5.4msec downloaded from: http:///
technical note 12/20 bd9757mw v www.rohm.com 2010.1 1 - rev . a ? 2010 rohm co., ltd. all rights reserved. b loc k e x pl anat io n 1. vrega it is a regulator with output voltage of 2.5v and used as a power supply of internal block. in addition, it outputs to outside from vrega terminal (32pin). 1.0 f is recommended as an external capacitor for oscillation prevention. 2. scp, timer latch it is a timer latch type of short-circuit protection circuit. for ch1,2, 6 ~ 8, the error amp output voltage is monito red, and detected when the feedback voltage deviates from control, for ch3 ~ 5, it is detect ed when the voltage of inv terminal becomes lower than 80%, and in 25ms the latch circuit operates and the outputs of all the channels are fixed at off. in order to reset the latch circuit, please turn off all t he stb terminals before turning them on once again or turning power supply on once again. 3. u.v.l.o (under voltage lockout) it is a circuit to prevent malfunction at low voltage. it is to prevent malfunction of internal circuit at the time of rising or dropping to a lower value of power supply voltage. if the voltage of vccout terminal becomes lower than 2.4v, then the output of eac h dc/dc converter is reset to off, and scps timer latch & soft start circuit are reset. when contro l is deviated from, the operat ion of ch1 at the time of start-up will be explained in start up osc mentioned later. 4. voltage reference (vref6) for the reference voltage circuit of ch6 inversion ch, th e output voltage is 1v and ou tputted from vref6 terminal (30pin). according this voltage and the output voltage of ch6, the dividing resi stance (resistor) is set and then the output voltage is set. if stb6 terminal is made to be h level at the time of start-up, then increase gradually the voltage up to 1v. the inversion output of ch6 follows this voltage and performs the soft start. 1.0 f is recommended as the external capacitor. 5. osc it is an oscillation circuit the frequency of which is fixed by a built-in cr. the operating frequencies of ch1 ~ ch5 ar e set at 1.2mhz, and the operating fr equencies of ch6 ~ ch8 are set at 600khz. 6. erramp 1 ~ 8 it is an error amplifier to detect output signal and output pw m control signal. the reference voltages of erramp (error amplifier) of ch1, 2,3,4,5 are inte rnally set at 0.8v, and the reference voltages of erramp (error amplifier) of ch7.8 are set at 1.0v. the reference voltage of ch6 is set at gnd potential, and for ch8s erramp81, the maximum value of the reference voltage is set at 0.4v. in addition, each ch incorporates a built-in element for phase compensation. 7. errcomp , start up osc it is a comparator to detect the output voltage and control t he start circuit, and also an oscillator that is turned on/off by this comparator and starts operating from 1.5v. the frequency of this oscillator is about 300 khz fixed internally. this oscillator stops operating if vcc terminal becomes more than 2.6v or the soft start time is exceeded. 8. current mode control block ch1 ~ 5 adopt the pwm method based on current mode. for a current- mode dc/dc converter, fet at the main side of synchronous rectif ication is turned on when detecting the clks edge, and turned off by detecting the peak current by means of the current comparator. 9. pwm comp pwm converter is a voltage-pulse width converter to control output voltage according to input voltage. it compares the output voltage of error amplifier with the slope waveform, cont rols the pulse width and outputs to driver. the driver is turned on during the output of error amplifier being highe r than slope waveform. the maximum on duty is set at about 92% internally. downloaded from: http:///
technical note 13/20 bd9757mw v www.rohm.com 2010.1 1 - rev . a ? 2010 rohm co., ltd. all rights reserved. 10. nch driver , pch driver it is a cmos inverter type of output circuit to drive both built-in and external nch,pch fet. 11. load switch it is a circuit, mounted in ch7, 8, to control the load switch. hs78h terminal (36pin) is input terminal, and the hs67 and hs78 terminals (40,37pin) are output terminals. this control circuit can prevent the rush current at the time of switch on because the soft start starts functioning at the time of start-up. in addition, this load switch is prov ided with ocp function to prevent the ic from damage. ensure that the ic is used within load switchs rated current when used normally. 12. on/off logic it is the voltage applied to stb terminal and can control the on/off of ch1 ~ ch7. if the voltage more than 1.5v is applied, then it becomes on, but if open or 0v is applied, then it becomes off, furthermore, it all the channels are turned off, then the whol e ic will be in standby state. in addition, stb13 ~ stb7 terminals contain respectively a built-in pull-down resistor of about 400k ? . upic8 is the input terminal of the start signal and the light control signal of ch8. it becomes high if the voltage more than 2.1v is applied and becomes low if the voltage less than 0.4v is applied. in addition, upic8 termi nal contains a built-in pull-down resistor of about 50k ? . 13. soft start it is a circuit to apply the soft start to the output voltage of dc/dc converter and prevent the rush current at the start-up. soft start time varies with the channels. a. ch1 ????? reaches the target voltage in 3.0 msec. b. ch3,4 ????? reaches the target voltage in 2.2 msec. c. ch2,5,6 ????? reaches the target voltage in 4.4 msec. d. ch7,8 ????? reaches the target voltage in 5.4 msec. downloaded from: http:///
technical note 14/20 bd9757mw v www.rohm.com 2010.1 1 - rev . a ? 2010 rohm co., ltd. all rights reserved. ch 8 mo du late d l i g h t fun c tion e x pl an ati on description of ch8 operation en, the signal for getting ch8 operated, is turned to h (en=h) by maintaining the h interval that is shown by t en and from upic8 terminal (refer to fig.29 en start-up-g) . en signal is turned to l and ch8 is turned off by maintaining the l interval that is shown by t off and from upic8 terminal (refer to fig.29 en start-up-k ~ l) . moreover, upic8 terminal will not become l ever since en starting-up, and if the h interval shown by t on is passed, then the dac input data (dacin [4:0]) for setting of inv8i output vo ltage is started up by the state of max voltage setting (1fh) (refer to fig.29 fullon mode-h ~ i). as for the method to set the values except max voltage as inv8i voltage, first fix the upic8 terminal on interval l shown by t clr and then reset the counter for tone setting, before inputting only the number of times equivalent to the tone intended for setting the upic8 terminals rising edge. right after that, if it is fixed on interval h shown by t on , then the number of count is latched, transmitted to dac, and the voltage of inv8i is switched to the set voltage. at the time of setting again, please repeat this operation (procedure). for the frequency of pulse inputted to upic8 terminal, please follow the rules of t h and t l. (refer to fig.29 normal mode-k ~ n, and refer to p.2 for the rules). once the counter for tone setting reaches 31, 1fh remains unchanged no matter how many times it is counted. if the counter for tone setting needs to be cleared, please input the interval l of t clr . if the pulses less than t clr is continued to be inputted to upic8 terminal after en becomes h (en=h) at the time of starting up, then the value of counter for tone setting is undet ermined, and dac for inv8i output voltage setting is turned off, therefore, please determine the se t value with the time shown by t set . furthermore, for the possible setting range of inv8i output vo ltage value, please refer to p.16(fig.30 led current value setting). points for attention at the time of ch8 starting up soft start is started when light control setting signal is inpu tted from upic8 terminal. at this moment it is necessary to make any one of stb1 ~ 7 to be h, if osc does not start o scillating after vrega is start ed and uvlo is released, then ch8 does not start up. at the time of starting up there is no voltage enough for turn ing on the led, so the feedba ck on the side of inv8i does not return,and it is soft-started by th e voltage feedback from vo8 to inv8. before the soft start internal is ended, the feedback (retu rn) based on any current setting which is according to light control setting is started. after soft-start ing, any current setting is performed by changing the light control setting signal. ch8 is turned off by making upic8 terminal to be l for a certain period of time. moreover, the interval of about 5.4ms from the time of upic8 terminals rising is taken as the soft start interval, and the soft start is applied according to the current value originally set by light control from upic8 terminal. the change of light control setting excepting turning off dur ing this interval is not reflected. recommended method of setting at the time of inv8i output voltage setting if inv8i output setting value is made larger than previous setting value during all intervals but soft start interval (at the time of starting up), it is recommended t hat the value of voltage is increased step by step with the smallest possible width of step after fully evaluating the restrict ion at the soft side that controls rush current and switching and the vision of brightness etc. in terms of set application. + - + + - + + - + osc pwm comp8 erramp 8i erramp 8v n-ch driver vccout load sw vccout ocp hs78h inv8i vbat vo8(feed back ch8) led soft start dac en stby uvlo ss_clk en inv8 inv8i upic8 pgnd678 lx8 hs8l hs78h to scp 1.0v en logic dacin[5:0] counter for tone setting reaches 31 (5bit) vrega_d detect counter for h section (6bit) count[4:0] latch vrega1 se l 5->6bit decode 1fh(fixed) p&r area reset gen uvlo i/o (schmitt) led current setting resister r detect counter for l section (6bit) fig.28 ch8 block diagram downloaded from: http:///
technical note 15/20 bd9757mw v www.rohm.com 2010.1 1 - rev . a ? 2010 rohm co., ltd. all rights reserved. e x pl a nati on o n o p e rat i o n of c h 8 5b i t co un ter + r e g i ster fig.29 timing chart downloaded from: http:///
technical note 16/20 bd9757mw v www.rohm.com 2010.1 1 - rev . a ? 2010 rohm co., ltd. all rights reserved. upic8 rising edge count dac input dacin[4:0] inv8i output voltage [v] 1 01h 0.100 2 02h 0.110 3 03h 0.120 4 04h 0.130 5 05h 0.140 6 06h 0.150 7 07h 0.160 8 08h 0.170 9 09h 0.180 10 0ah 0.190 11 0bh 0.200 12 0ch 0.210 13 0dh 0.220 14 0eh 0.230 15 0fh 0.240 16 10h 0.250 17 11h 0.260 18 12h 0.270 19 13h 0.280 20 14h 0.290 21 15h 0.300 22 16h 0.310 23 17h 0.320 24 18h 0.330 25 19h 0.340 26 1ah 0.350 27 1bh 0.360 28 1ch 0.370 29 1dh 0.380 30 1eh 0.390 31 1fh 0.400 fig.30 led current setting (note 1) led current = inv8i voltage / resistance r for led current setting downloaded from: http:///
technical note 17/20 bd9757mw v www.rohm.com 2010.1 1 - rev . a ? 2010 rohm co., ltd. all rights reserved. se ttin g me th od o f ic p eri ph eral co mp on en t s (1) design of feedback resistor constant ch1 5 output voltage ch6 output voltage ? ? (1) ]v[ 8.0 2r 2r 1r v o ??? ? ? ? (2) ]v[ 0.1 1r 2r v o ??? ? ?? ch7,8 output voltage ch8 output voltage ? ? (3) ]v[ 0.1 2r 2r 1r v o ??? ? ? ? (4) ]a[ 3r i8 inv i o ??? ? fig.31 feedback resistor setting method (a) ch1 ~ 5 setting the reference voltage of ch1 ~ 5s error amp is 0.8v. please refer to formula (1) in fig.31 for determining the output voltage. this ic incorporates built-in phase compensation. please refer to applied circuit diagram for setting the values of r1 & r2 and ensure that the setting values of r1 & r2 are of the order of several hundred k ? . (b) ch6 setting the reference voltage of ch6s error amp is connected to gnd inside the ic. therefore, a high-accuracy regulator can be configured if setting by the feedback resistance between the outputs of vref and ch5 as shown in fig.31. please refer to formula (2) in fig.31 for determining the output voltage. r1 is recommended as more than 20k ? because the current capacity of vref is about 100 a. (c) ch7 setting the reference voltage of ch7s error amp is 1.0v. please refer to formula (3) in fig.31 for determining the output voltage. (d) ch8 setting in the ch8 there are two error amps which have diff erent standards, and when used with constant current feedback applied unilaterally to backlight etc., the over voltage protection can be operated unilaterally. over voltage setting and output current setting are respectively shown in formula (3) and (4) in fig.31. the outputs of these two error amps are controlled with l being given priority. therefore, when used under the control of only either of the two ensure that the inv terminal is used as gnd short. ch6, ch7, and ch8 are of voltage mode control. ensure that ch6, 7 and 8 are used by means of discontinuous inductor current so as to secure the oscillation margin. (2) points for attention in terms of pcb layout of base-plate for a switching regulator, in principle a large current transiently flows through the route of power supply - coil - output capacitor. ensure that the wiring impedance is lowered as much as possible by making the pattern as wide as possible and the layout as short as possible. interference of power supply noise with feedback terminals (inv1 ~ 8i,non6) may cause the output voltage to oscillate. ensure that the power supply noises interference is avoided by making the wiring between feedback resistor and feedback terminal as short as possible. vref 1.0v vout7 error amp r1 r2 inv reference voltage is connected to gnd inside ic vref6 error amp r1 r2 non vout6 vref 0.8v vout1 5 error amp r1 r2 inv vout8 vref 1.0v error amp8v r1 r2 inv8 vref error amp7i r3 inv8i upic8 setting according to number of counts (refer to fig.29 of page 15) output level l takes priority downloaded from: http:///
technical note 18/20 bd9757mw v www.rohm.com 2010.1 1 - rev . a ? 2010 rohm co., ltd. all rights reserved. pi n e q u iva lent c irc uit fig.32 pin equivalent circuit inv1 inv8,inv8i (error amplifiers inversion input) non6 (error amplifiers non-inversion input) vrega (rega output) vref6 (ch6 standard voltage output) stb13, stb2, stb4, stb5, stb6, stb7 (operating when ch1~7 on/off switch is high) hx1,2,3,4,5(pch fet source terminal) lx1,2,3,4,5(nch,pch fet drain terminal) pgnd13,24,5 (output stage earthing terminal) lx7, 8 (nch fet drain terminal) pgnd678 hs78h (high side sw input terminal) hs7l, 8l (high side sw output terminal) out5(ch5 power-mosfet connection) pgnd567 (output stage earthing) upic8 (ch8 start signal, led modulated light signal input) vccout vrega vccout vrega vccout vref6 vccout inv vrega vccout non6 vrega vccout stb vccout pgnd lx hx hs78h hs7l,8l lx7,8 pgnd678 vccout out6 vccout pgnd678 vccout vccout vrega upic8 downloaded from: http:///
technical note 19/20 bd9757mw v www.rohm.com 2010.1 1 - rev . a ? 2010 rohm co., ltd. all rights reserved. n o t e s fo r use 1.) absolute maximum ratings although the quality of this product has been tightly controlled, deterioration or even destruction may occur if the absolu te maximum ratings, such as for applied pressure and operati onal temperature range, are exceeded. furthermore, we are unable to assume short or open mode destruction conditions. if special modes which exceed the absolute maximum ratings are expected, physical safely precau tions such as fuses should be considered. 2.) gnd potential the potential of the gnd pin should be at the minimum potentia l during all operation status. in addition, please try to do not become electric potential below gnd for the terminal othe r than non6 including the transient phenomenon in practice. please do not go down below 0.3v for the non6 terminal with transient phenomenon and the like when you use. 3.) heat design heat design should consider tolerance dissipation (pd) during actual use and margins which should be set with plenty of room. 4.) short-circuiting between terminals and incorrect mounting when attaching to the printed substrate, pay special attention to the direction and proper placement of the ic. if the ic is attached incorrectly, it may be destroyed. destruction can also occur when there is a short, which can be caused by foreign objects entering between ouputs or an output and the power gnd. 5.) operation in strong magnetic fields exercise caution when operating in strong magnet fields, as errors can occur. 6.) about common impedance please do sufficient consideration for the wiring of power so urce and gnd with the measures such as lowering common impedance, making ripple as small as possible (making the wiring as thick and short as possible, dropping ripple from l.c) and the like. 7.) stb terminal voltage please set stb terminal voltage below 0.3v when each channel is put in stand-by state, and set it above 1.5v when each channel is put in working condition. please use the condenser below 0.01 f when the condenser is connected to the stb terminal. as it will become the cause of the malfunction. 8.) heat protection circuit (tsd circuit) this ic has a built-in temperature protection circuit (tsd circ uit). the temperature protection circuit (tsd circuit) is only to cut off the ic from thermal runaway, and has not been de signed to protect or guarantee t he ic. therefore, the user should not plan to activate this circuit with continued operation in mind. 9.) because there are times when rush current flows instantaneously in internal logical uncertain state at the time of pow er source turning on with cmos ic, please pay attention to the power source coupling capacity, the width of gnd pattern wiring and power source, and the reel. 10.) because there are times when rush current flows instantaneously due to the order of power source throwing in, lag with cmos ic where it has plural power sources, please pay att ention to the power source coupling capacity, the width of gnd pattern wiring and power source, and the reel. 11.) ic terminal input this ic is a monolithic ic, and between each element there is a p+ isolation and p substrate for element separation. there is a p-n junction formed between this p-layer and eac h elements n-layer, which makes up various parasitic elements. for example, when resistance and transistor are connected with a terminal as in fig.33: when gnd>(terminal a) at the resistance, or gnd>(terminal b) at the transistor (npn), the p-n junction operates as a parasitic diode. also, when gnd>(terminal b) at the transistor, a parasitic npn transistor operates by the n-layer of other elements close to the aforementioned parasitic diode. with the ics configuration, the production of parasitic elements by the relationships of the electrical potentials is inevitable. the operation of the parasitic elements can also interfere with the circuit operation, leading to malfunction and even destruction. therefore, uses which cause the para sitic elements to operate, such as applying voltage to the input terminal which is lower than the gnd (p-substrate), should be avoided. fig.33 simple structure of bipolar ic (sample) (terminal a) parasitic element transistor (npn) gnd p board n p n n p + p + (terminal b) b n e c gnd (terminal a) gnd parasitic element gnd p board n p n n p + p + parasitic element resistance downloaded from: http:///
technical note 20/20 bd9757mw v www.rohm.com 2010.1 1 - rev . a ? 2010 rohm co., ltd. all rights reserved. or der in g p a rt n u mb er b d 9 7 5 7 m w v - e 2 part no. part no. package mwv: uqfn044v6060 packaging and forming specification e2: embossed tape and reel (unit : mm) uqfn044v6060 0.08 s s 1pin mark 23 33 34 44 12 11 1 22 0.02 +0.03 - 0.02 0.2 +0.05 - 0.04 c0.2 0.4 1.0 6.0 0.1 3.7 0.1 0.5 0.1 3.7 0.1 6.0 0.1 1.0max (0.22) ? order quantity needs to be multiple of the minimum quantity. embossed carrier tape 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 2000pcs 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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