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20211 sy/51210 sy 20100216-s00005 no.a1674-1/14 http://onsemi.com semiconductor components industries, llc, 2013 june, 2013 LV8712T overview the LV8712T is a stepping motor driver of the micro-step drive corresponding to supports 2w 1-2 phase excitation. it is the best for the drive of the stepping motor for a scanner and a small printer. features ? single-channel pwm constant-current control stepping motor driver incorporated. ? excitation mode can be set to 2-phase, 1-2 phase, w1-2 phase , or 2w1-2 phase ? microstep can control easily by the clk-in input. ? power-supply voltage of motor : vm max = 18v ? output current : i o max = 0.8a ? output on resistance : r on = 1.1 ? (upper and lower total, typical, ta = 25 c ) ? a thermal shutdown circuit and a low voltage detecting circuit are built into. specifications absolute maximum ratings at ta = 25 c parameter symbol conditions ratings unit motor supply voltage vm max 18 v logic supply voltage v cc max 6 v output peak current i o peak each 1ch, tw 10ms, duty 20% 1.0 a output continuousness current i o max each 1ch 800 ma logic input voltage v in -0.3 to v cc + 0.3 v allowable power dissipation pd max * 1.35 w operating temperature topr -20 to +85 c storage temperature tstg -55 to +150 c * specified circuit board : 57.0mm 57.0mm 1.7mm, glass epoxy 2-layer board. bi-cmos lsi pwm constant-current control stepping motor driver orderin g numbe r : ena1674a stresses exceeding maximum ratings may damage the device. maximum ratings are stress ratings only. functional operation above the recommended oper ating conditions is not implied. extended exposure to stresses above the recommended operating conditions may affect device reliabili ty.
LV8712T no.a1674-2/14 allowable operating ratings at ta = 25 c parameter symbol conditions ratings unit motor supply voltage range vm 4 to 16 v logic supply voltage range v cc 2.7 to 5.5 v logic input voltage v in -0.3 tp v cc +0.3 v vref input voltage range vref 0 to v cc -1.8 v electrical characteristics at ta = 25c, vm = 12v, v cc = 3.3vvref = 1.0v ratings parameter symbol conditions min typ max unit imstn ps = ?l?, no load 1 a standby mode current drain i cc stn ps = ?l?, no load 1 a im ps = ?h?, no load 0.3 0.5 0.7 ma current drain i cc ps = ?h?, no load 0.9 1.3 1.7 ma thermal shutdown temperature tsd design guarantee 180 c thermal hysteresis width tsd design guarantee 40 c v cc low voltage cutting voltage vthv cc 2.1 2.4 2.7 v low voltage hysteresis vo ltage vthhis 100 130 160 mv reg5 output voltage vreg5 i o = -1ma 4.5 5 5.5 v ronu i o = -800ma, source-side on resistance 0.78 1.0 output on resistance rond i o = 800ma, sink-side on resistance 0.32 0.43 output leakage current i o leak v o = 15v 10 a diode forward voltage vd id = -800ma 1.0 1.2 v i in l v in = 0.8v 4 8 12 a logic pin input current i in h v in = 3.3v 22 33 45 a logic high-level input voltage v in h 2.0 v logic low-level input voltage v in l 0.8 v vref input current i ref vref = 1.0v -0.5 a vtdac0_2w step 0 (when initialized : channel 1 comparator level) 0.191 0.2 0.209 v vtdac1_2w step 1 (initial state+1) 0.187 0.196 0.205 v vtdac2_2w step 2 (initial state+2) 0.175 0.184 0.193 v vtdac3_2w step 3 (initial state+3) 0.158 0.166 0.174 v vtdac4_2w step 4 (initial state+4) 0.132 0.140 0.148 v vtdac5_2w step 5 (initial state+5) 0.102 0.110 0.118 v vtdac6_2w step 6 (initial state+6) 0.068 0.076 0.084 v 2w1-2-phase drive vtdac7_2w step 7 (initial state+7) 0.032 0.040 0.048 v vtdac0_w step 0 (when initialized : channel 1 comparator level) 0.191 0.200 0.209 v vtdac2_w step 2 (initial state+1) 0.175 0.184 0.193 v vtdac4_w step 4 (initial state+2) 0.132 0.140 0.148 v w1-2-phase drive vtdac6_w step 6 (initial state+3) 0.068 0.076 0.084 v vtdac0_h step 0 (when initialized : channel 1 comparator level) 0.191 0.200 0.209 v 1-2 phase drive vtdac4_h step 4 (initial state+1) 0.132 0.140 0.148 v current setting comparator threshold voltage (current step switching) 2 phase drive vtdac4_f step 4' (when initialized : channel 1 comparator level) 0.191 0.200 0.209 v vtatt00 att1 = l, a tt2 = l 0.191 0.200 0.209 v vtatt01 att1 = h, a tt2 = l 0.152 0.160 0.168 v vtatt10 att1 = l, a tt2 = h 0.112 0.120 0.128 v current setting comparator threshold voltage (current attenuation rate switching) vtatt11 att1 = h, a tt2 = h 0.072 0.080 0.088 v chopping frequency fchop cchop = 220pf 36 45 54 khz v chop h 0.6 0.7 0.8 v chop pin threshold voltage v chop l 0.17 0.2 0.23 v chop pin charge/discharge current ichop 7 10 13 a moni pin saturation voltage vsatmon imoni = 1ma 250 400 mv
LV8712T no.a1674-3/14 package dimensions unit : mm (typ) 3260a pin assignment ambient temperature, ta - c allowable power dissipation, pd max - w pd max - ta 0 0.5 1.0 1.5 1.35 0.70 - 20 40 60 80 20 0 100 specified circuit board : 57.0 57.0 1.7mm 3 2-layer glass epoxy board sanyo : tssop24(225mil) 6.4 0.5 4.4 (0.5) (1.0) 6.5 0.5 0.15 1 12 24 13 0.22 0.08 1.2max rst oe reg5 1 2 3 4 5 6 7 8 9 10 11 12 24 23 22 21 20 19 18 17 16 15 14 13 LV8712T ps moni vref step att1 att2 chop v cc gnd fr out1a pgnd rnf1 out1b vm out2a rnf2 out2b pgnd md1 md2
LV8712T no.a1674-4/14 block diagram att1 att2 pgnd moni oe rst step fr md2 md1 chop tsd lvs vref gnd v cc rnf1 out1a out1b out2a out2b rnf2 vm + - + - + - + - 1/5 ps + - reg5 output preamplifier stage output control logic current selection (2w1-2/ w1-2/1-2/2) current selection (2w1-2/ w1-2/1-2/2) oscillation circuit output preamplifier stage output preamplifier stage output preamplifier stage attenuator (100%/80% /60%/40%) vm-5v standard voltage standard voltage start circuit
LV8712T no.a1674-5/14 pin functions pin no. pin name pin functtion equivalent circuit 1 2 7 8 9 13 14 24 rst oe step att1 att2 md2 md1 fr excitation reset signal input pin. output enable signal input pin. step signal input pin. motor holding current switching pin. motor holding current switching pin. excitation mode switching pin 2. excitation mode switching pin 1. cw / ccw switching signal input pin. v cc gnd 4 ps power save signal input pin. v cc gnd 4 16 17 18 20 21 23 out2b rnf2 out2a out1b rnf1 out1a channel 2 outb output pin. channel 2 current-sense resistor connection pin. channel 2 outa output pin. channel 1 outb output pin. channel 1 current-sense resistor connection pin. channel 1 outa output pin.power gnd 21 17 vm 18 23 16 20 6 vref constant curre nt control reference voltage input pin. gnd 6 v cc continued on next page.
LV8712T no.a1674-6/14 continued from preceding page. pin no. pin name pin functtion equivalent circuit 3 reg5 internal power supply capacitor connection pin. gnd 3 v m 5 moni position detection monitor pin. gnd 5 v cc 10 chop chopping frequency setting capacitor connection pin. gnd 10 v cc
LV8712T no.a1674-7/14 description of operation stepping motor control (1) power save function this ic is switched between standby and operating mode by setting the ps pin. in standby mode, the ic is set to power-save mode and all logic is reset. in addition, the internal regulator circuit do not operate in standby mode. ps mode internal regulator low or open standby mode standby high operating mode operating (2) the order of turning on recommended power supply the order of turning on each power supply recommends the following. vcc power supply order vm power supply order ps pin = high it becomes the above-mentioned opposite for power supply off. however, the above-mentioned is a recommendation, the overcurrent is not caused by not having defended this, and ic is destroyed. (3) step pin function input ps stp operating mode low * standby mode high excitation step proceeds high excitation step is kept (4) excitation mode setting function(initial position) initial position md1 md2 excitation mode channel 1 channel 2 low low 2 phase excitation 100% -100% high low 1-2 phase excitation 100% 0% low high w1-2 phase excitation 100% 0% high high 2w1-2 phase excitation 100% 0% this is the initial position of each excitation mode in th e initial state after power-on and when the counter is reset. (5) position detection monitoring function the moni position detection monitoring pin is of an open drian type. when the excitation position is in the initial positi on, the moni output is placed in the on state. (refer to "(12) examples of current wave forms in each of the excitation modes.")
LV8712T no.a1674-8/14 (6) reset function rst operating mode high normal operation low reset state when the rst pin is set to low, the excitation position of the output is forcibly set to the initial position, and the moni output is placed in the on state. when rst is then set to high, the excitation position is advanced by the next step input. (7) output enable function oe operating mode low output on high output off when the oe pin is set high, the output is forced off and goes to high impedance. however, the internal logic circuits are operating, so th e excitation position proceeds when the step signal is input. therefore, when oe is returned to low, the output level conforms to the excitation position proceeded by the step input. oe power save mode 0% step moni 1ch output 2ch output output is high-impedance rst reset 0% step moni 1ch output 2ch output initial position
LV8712T no.a1674-9/14 (8) forward/reverse switching function fr operating mode low clockwise (cw) high counter-clockwise (ccw) the internal d/a converter proceeds by one bit at the rising edge of the input step pulse. in addition, cw and ccw mode are switched by setting the fr pin. in cw mode, the channel 2 current phase is delayed by 90 relative to the channel 1 current. in ccw mode, the channel 2 current phase is adva nced by 90 relative to the channel 1 current. (9) setting constant-current control the setting of stm driver's constant current control is decided the vref voltage from the resistance connected between rnf and gnd by the following expression. i out = (vref/5)/rnf resistance * the above setting is the output current at 100% of each excitation mode. the voltage input to the vref pin can be switched to four-step settings depending on the statuses of the two inputs, att1 and att2. this is effective for reducing power consumption when motor holding current is supplied. attenuation function for vref input voltage att1 att2 current setting reference voltage attenuation ratio low low 100% high low 80% low high 60% high high 40% the formula used to calculate the output current when using the function for attenuating the vref input voltage is given below. i out = (vref/5) (attenuation ratio)/rnf resistance example : at vref of 1.0v, a reference voltage setting of 100% [(att1, att2) = (l, l)] and an rnf resistance of 0.5 , the output current is set as shown below. i out = 1.0v/5 100%/0.5 = 400ma if, in this state, (att1, att2) is se t to (h, h), iout will be as follows : i out = 400ma 40% = 160ma in this way, the output current is attenuated when th e motor holding current is supplied so that power can be conserved. fr cw mode cw mode ccw mode step excitation position 1ch output 2ch output (1) (2) (3) (4) (5) (6) (5) (4) (3) (4) (5)
LV8712T no.a1674-10/14 (10) chopping frequency setting for constant-current control, this ic performs chopping operations at the frequency determined by the capacitor (cchop) connected between the chop pin and gnd. the chopping frequency is set as shown below by the capacitor (cchop) connected between the chop pin and gnd. tchop c v 2 / i (s) v : width of suresshu voltage, typ 0.5v i : charge/discharge current, typ 10 a for instance, when cchop is 200pf, the chopping frequency will be as follows : fchop 1 / tchop (hz) (11) output current vector locus (one step is normalized to 90 degrees) setting current ration in each excitation mode 2w1-2 phase (%) w1-2 phase (%) 1-2 phase (%) 2-phase (%) step channel 1 channel 2 channel 1 channel 2 channel 1 channel 2 channel 1 channel 2 0 100 0 100 0 100 0 1 98 20 2 92 38 92 38 3 83 55 4 70 70 70 70 70 70 100 100 5 55 83 6 38 92 38 92 7 20 98 8 0 100 0 100 0 100 channel 2 current ratio (%) 4' (2-phase) channel 1 phase current ratio (%) 0.0 33.3 66.7 100.0 0.0 33.3 66.7 100.0 0 1 3 5 6 7 8 2 4
LV8712T no.a1674-11/14 (12) typical current waveform in each excitation mode 2-phase excitation (cw mode) 1-2 phase excitation (cw mode) step moni l1 (%) (%) -100 -100 100 100 0 0 i2 step moni i1 (%) -100 -100 100 (%) 100 0 0 i2
LV8712T no.a1674-12/14 w1-2 phase excitation (cw mode) 2w1-2 phase excitation (cw mode) step moni i1 -100 (%) 100 50 -50 0 i2 -100 (%) 100 50 -50 0 step moni i1 (%) -100 -100 100 (%) 100 0 0 i2
LV8712T no.a1674-13/14 (13) current control timing chart(chopping operation) (sine wave increasing direction) (sine wave decreasing direction) in each current mode, the operation sequence is as described below : ? at rise of chopping frequency, the charge mode begins. (the blanking section in which the charge mode is forced regardless of the magnitude of the coil cu rrent (icoil) and set current (iref) exists for 1 s.) ? the coil current (icoil) and set current (ir ef) are compared in this blanking time. when (icoil < iref) state exists ; the charge mode up to icoil iref, then followed by changeover to the slow decay mode, and finally by the fast decay mode for approximately 1 s. when (icoil < iref) state does not exist ; the fast decay mode begins. the coil current is a ttenuated in the fast decay mode till one cycle of chopping is over. above operations are repeated. normally , the slow (+fast) decay mode continues in the sine wave increasing direction, then entering the fast decay mode till the curren t is attenuated to the set level and followed by the slow decay mode. fast slow charge fast slow charge current mode fchop coil current step set current set current fast slow fast slow charge current mode fchop coil current step set current set current forced charge section charge chopping cycle blanking section blanking section blanking section blanking section blanking section chopping cycle chopping cycle
LV8712T ps no.a1674-14/14 application circuit example the formulae for setting the constants in the examples of the application circuits above are as follows : constant current (100%) setting when vref = 1.0v i out = vref/5/rnf resistance = 1.0v/5/0.51 = 0.392a chopping frequency setting fchop = ichop/ (cchop vtchop 2) = 10 a/ (220pf 0.5v 2) = 45khz logic input clock input short-circuit state detection monitor + - 220pf 12v 1.0v + - m reg5 1 2 3 4 5 6 7 8 9 10 11 12 24 23 22 21 20 19 18 17 16 15 14 13 LV8712T ps moni vref step att1 att2 chop v cc gnd fr out1a pgnd rnf1 out1b vm out2a rnf2 out2b pgnd md1 md2 oe rst + - 3.3v logic input logic input on semiconductor and the on logo are registered trademarks of semiconductor components industries, llc (scillc). scillc owns the rights to a number of patents, trademarks, copyrights, trade secrets, and other intellectual property. a listing of scillc?s product/patent coverage may be accessed at www.onsemi.com/site/pdf/patent-marking.pdf. scillc reserves the right to make changes without further notice to any products herein. scillc mak es no warranty, representation or guarantee regarding the suitability of its products for any particular purpose, nor does scillc assume any liability ar ising out of the application or use of any product or circuit, and specifically disclaims any and all liability, including without limitation special, consequentia l or incidental damages. ?typical? parameters which may be provided in scillc data sheets and/or specifications can and do vary in different applications and actual performance may vary over time. all operating parameters, including ?typicals? must be validated for each customer application by customer?s techn ical experts. scillc does not convey any license under its patent rights nor the rights of others. scillc products are not designed, intended, or authorize d for use as components in systems intended for surgical implant into the body, or other applications intended to support or sustain life, or for any other appli cation in which the failure of the scillc product could create a situation where personal injury or death may occur. should buyer purchase or use scillc products for any such unintended or unauthorized application, buyer shall indemnify and hold scillc and its officers, employees, subsidiaries, affiliates, and distributors harmless against all claims, costs, damages, and expenses, and reasonable attorney fees arising out of, directly or indirectly, any claim of persona l injury or death associated with such unintended or unauthorized use, even if such claim alleges that scillc was negligent regarding the design or manufacture o fthe part. scillc is an equal opportunity/affirmative action employer. this literature is subject to all applicable copyright laws a nd is not for resale in any manner.

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