71608hkim/61504tn (ot) no.7465-1/10 http://onsemi.com semiconductor components industries, llc, 2013 june, 2013 STK672-220-E overview the STK672-220-E is two-phase stepping motor driver hybrid ic (hic) that features further miniaturization and improved input logic flexibility as compared to the stk6713 series products. applications ? the STK672-220-E is optimal for use as a stepping motor driver in printers , copiers, xy plotters, and similar equipment. features ? built-in common-mode input protection circuit. ? the input signal logic lines are provi ded as active-high and active-low pairs, and thus support switching the motor wiring. ? built-in current detection resistor for reduced external component mounting area on the printed circuit board. ? inhibit pin (cuts off the motor current) ? wide motor operating range (10 to 45v) ordering number : en7465a thick-film hybrid ic unipolar constant-current chopper two-phase stepping motor driver output current 2.8a
STK672-220-E no.7465-2/10 specifications absolute maximum ratings at tc = 25 c parameter symbol conditions ratings unit maximum supply voltage 1 v cc 1 max no signal 52 v maximum supply voltage 2 v cc 2 max no signal -0.3 to +7.0 v input voltage v in max logic input pins -0.3 to +7.0 v output current i oh max 0.5s, 1 pulse, when v cc 1 is applied 3.3 a allowable power dissipation pd max with an arbitrarily large heat sink. per mosfet 9 w operating substrate temperature tc max 105 c junction temperature tj max 150 c storage temperature tstg -40 to +125 c allowable operating ranges at ta = 25 c parameter symbol conditions ratings unit supply voltage 1 v cc 1 with signals applied 10 to 45 v supply voltage 2 v cc 2 with signals applied 5.0 5% v input voltage v ih 0 to v cc 2v phase driver withstand voltage v dss i d = 1ma (tc = 25c) 100 v output current 1 i oh 1 clk 200hz, tc = 105c 2.8 a output current 2 i oh 2 clk 200hz, tc = 80c 3a electrical characteristics at tc = 25 c, v cc 1 = 24v, v cc 2 = 5v rating parameters symbols conditions min typ max unit control supply current i cco with all inputs at the v cc 2 level 3.3 10 ma output average current ioave with r/l = 3.5 /3.8mh in each phase 0.549 0.610 0.671 a fet diode forward voltage vdf if = 1.0a 1.1 1.8 v output saturation voltage vsat r l = 12 0.7 1.2 v vref input voltage vrh pin 12 0 3.5 v vref input bias current i ib with pin 12 at 1v 50 500 na [control input pins] v ih hic pins 6, 7, 8, 9, and 11 3.5 v input voltage v il hic pins 6, 7, 8, 9, and 11 0.7 v i ih hic pins 6, 7, 8, 9, and 11, v in = v cc 2 310 a input current i il hic pins 6, 7, 8, 9, and 11, v in = 0v 2.5 a note: a fixed-voltage power supply must be used. package dimensions unit:mm (typ) 4167 1 12 46.6 41.2 12.7 25.5 (9.6) 11 2=22 3.6 0.5 2.0 8.5 4.0 0.4 2.9 1.0 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.
STK672-220-E no.7465-3/10 internal block diagram sample application circuit ? the co1 ground lead must be connected as close as possible to pin 1 on the hybrid ic. ? hc type cmos levels are recommended as the input specifications for pins 6 to 9. ? in case of ttl input, connect a pull- up resistor. (recommended value: 2k ) ? excitation control input specifications corresponding excitation control input signal corresponding output pin active: high active: low 2 pin b bb 3 pin bb b 4 pin a ab 5 pin ab a v cc 2 10 sub off time settin g off time settin g 4 5 = 9 8 7 6 12 1 10 stepping motor co2=10 + + ro1 ro2 s.gnd bb b ab a a t least v cc 1=24v co1=220 p.gnd 2 3 4 5 itf02299 11 inhibit
STK672-220-E no.7465-4/10 2-phase excitation 1-2 phase excitation phase signal: active high input 2-phase excitation phase signal: active low input 1-2 phase excitation pin 5 mosfet gate signal pin 4 mosfet gate signal pin 3 mosfet gate signal pin 2 mosfet gate signal pin 6 phase signal bb pin 7 phase signal b pin 8 phase signal ab pin 9 phase signal a clock pin 5 mosfet gate signal pin 4 mosfet gate signal pin 3 mosfet gate signal pin 2 mosfet gate signal pin 6 phase signal bb pin 7 phase signal b pin 8 phase signal ab pin 9 phase signal a clock pin 5 mosfet gate signal pin 4 mosfet gate signal pin 3 mosfet gate signal pin 2 mosfet gate signal pin 6 phase signal bb pin 7 phase signal b pin 8 phase signal ab pin 9 phase signal a clock pin 5 mosfet gate signal pin 4 mosfet gate signal pin 3 mosfet gate signal pin 2 mosfet gate signal pin 6 phase signal bb pin 7 phase signal b pin 8 phase signal ab pin 9 phase signal a clock
STK672-220-E no.7465-5/10 setting the motor current peak value (i oh ) i oh vref rs vref: STK672-220-E pin 12 input voltage rs: STK672-220-E internal current detection resistor (0.17 2%) model of the motor current flowing into the driver ic (pins 2, 3, 4, and 5) vref = (ro2 (ro1 + ro2)) v cc 2 v cc 2 = 5v current switching techniques due to the input bias current (i ib ) specifications, ro1 must be under 100k . the figures below present sample circuits that temporarily switch the motor current when, for example a held motor stops. we recommend using the circuit structure in the figure at th e left to minimize as much as possible the effects of the saturation voltage of the reference voltage switching transistor. switching circuit 1 switching circuit 2 input pin circuits input pin circuit type pin 6, 7, 8, and 9 pin 11 pin 12 i oh 0 5v ro1 ro3 ro2 vref ro1 ro3 ro2 vref 5v vref to one of the comparato r cr input gnd v cc 2 the 5v/gnd switch shows how toff time setting operates in the internal block diagram on page 3. when switched to gnd, pull-down with an input resistance of 20k is formed. mosfet gate signal 10k 5 v 10k 5v to xb phase xb phase pwm signal x phase (xb phase) inhibit 10k 10k gnd
STK672-220-E no.7465-6/10 thermal design the size of the heat sink required for the STK672-220-E depends on the output current i oh (a), the electrical characteristics of the motor, the excitation mode, and the basic drive frequency. the thermal resistance ( c-a) of the required heat sink can be determined from the following formula. (c/w) tc max: the STK672-220-E substrate temperature (c) ta: the STK672-220-E ambient temperature (c) pd: the average internal power dissipation in the STK672-220-E (w) for example, the required area for a heat sink made from 2mm thick aluminum can be determined from the graph at the right below. note that the ambient temperature is greatly in fluenced by the ventilation and air flow patterns within the application. this means that the size of the heat sink must be determined w ith care so that the STK672-220-E back surface (aluminum substrate) temperature tc in the mounted state never exceeds, under any conditions that might occur, the temperature tc = 105 c. STK672-220-E average internal power dissipation pd of the devices that contribute to the STK672-220-E average internal power supply, the devices with the largest power dissipation are the current control devices, the diodes that handle the regenerative cu rrent, the current detection resistor, and the predriver circuit. the following presents formulas for calculating the power dissipation for the different excitation (drive) modes. 2 phase excitation mode pd 2ex = (vsat + vdf) 0.5 clock i oh t2 + 0.5 clock i oh (vsat t1 + vdf t3) 1-2 phase excitation mode pd 1-2ex = (vsat + vdf) 0.25 clock i oh t2 + 0.25 clock i oh (vsat t1 + vdf t3) motor hold mode pd holdex = (vsat + vdf) i oh vsat: ron voltage drop + shunt resistor combined voltage vdf: fet internal diode + shunt resistor combined voltage clock: input clock (shows clock in the timing charts on page 4) figure 1 motor com current waveform model pd ta - max tc a - c = i oh 0a t1 t2 t3 itf01880 048121620 2 6 10 14 18 heat sink thermal resistance, c-a - c/w ic internal average power dissipation, pd - w c-a - pd 0 8 12 16 20 4 itf01881 10 23 57 100 1000 23 57 heat sink thermal resistance, c-a - c/w heat sink area, s - cm 2 c-a - s 1.0 5 7 2 3 10 100 5 7 2 3 no fin 23.0[c/w] tc max=105c g u a r a n te e d a m b i e n t t e m p e ra tu r e 40c 50c 60c no fin 23.0[c/w] mounted vertically convection cooling 2 m m t h i c k a l p l a t e ( w i t h n o s u r f a c e f i n i s h ) ( w i t h a f l a t b l a c k s u r f a c e f i n i s h ) c-a= (c/w) tc max--ta pd
STK672-220-E no.7465-7/10 t1: the time until the winding current reaches its rated current (i oh ) t2: the time in the constant-current control (pwm) region t3: the time from the point a phase signal is cut until the back emf current is dissipated. t1 = (?l/(r + 0.4)) in (1 ? ((r + 0.4)/v cc 1) i oh ) t3 = (?l/r) in ((v cc 1 + 0.4) / (i oh r + v cc 1 + 0.4)) v cc 1: motor supply voltage (v) l: motor inductance (h) r: motor winding resistance ( ) i oh : set motor output current wave height (a) the constant-current control time t2, and the time t (= t1 + t2 + t3) that the phase signal is on in each excitation mode are as follows. 2 phase excitation mode: t2 = (2/clock) ? (t1 + t3) 1-2 phase excitation mode: t2 = (3/clock) ? t1 determine the values for vsat and vdf by substitution using the graphs for vsat vs i oh and vdf vs i oh for the set current value for i oh . then judge whether or not a heat sink is requ ired from the determined average power dissipation for the STK672-220-E by comparison with the tc vs. pd graph. note that it is necessary to check the temperature rise in the actual application system case, since the STK672-220-E substrate temperature tc changes with the air convectio n conditions around the STK672-220-E when a heat sink without fins is used. output saturation voltage, vsat - v motor current, i o - a vsat - i o forward voltage, vdf - v motor current, if - a vdf - if input pin current, i ih , i il - a substrate temperature, tc - c i ih - tc reference voltage, vref - v motor current, i oh - a vref - i oh itf02300 012 4 3 0 1.0 1.5 2.0 2.5 0.5 itf02301 0 0.5 1.0 1.5 2.0 2.5 3.0 3.5 4.0 0.4 0 0.2 0.8 0.6 1.6 1.4 1.2 1.0 t c = 1 0 5 c 2 5 c 1 0 5 c t c = 2 5 c itf02303 0 20 40 60 80 100 120 1000 7 5 3 2 100 7 5 3 2 10 0.1 7 5 3 2 1.0 7 5 3 2 itf02302 0 0.5 1.0 1.5 2.0 2.5 3.0 3.5 0.6 0.5 0 0.1 0.4 0.3 0.2 i ih i il
STK672-220-E no.7465-8/10 STK672-220-E allowable avalanche energy value [allowable range in avalanche mode] when driving a 2-phase stepping motor with constant current chopping using an stk672-2** series hybrid ic, the waveforms shown in figure 1 belo w result for the output current, i d , and voltage, v ds . figure 1 output current, i d , and voltage, v ds , waveforms 1 of the stk672-2** series when driving a 2-phase stepping motor with constant current chopping v dss : voltage during avalanche operations i oh : motor current peak value iavl: current during avalanche operations tavl: time of avalanche operations v ds i d itf02557 motor current, i oh - a substrate temperature, tc - c i oh - tc motor current, i oh - a substrate temperature, tc - c i oh - tc input frequency, clk - hz substrate temperature rise, tc - c hybrid ic internal power dissipation, pd - w tc - pd substrate temperature rise, tc - c tc - clk itf02304 0 20 40 60 80 100 120 0.5 1.0 1.5 2.0 2.5 0 itf02307 020 10 40 60 80 100 30 50 70 90 110 1.5 2.0 2.5 3.0 3.5 1.0 itf02306 100 23 57 1000 23 57 10000 10 20 30 40 50 60 70 80 0 itf02305 0 0.5 1.0 1.5 2.0 2.5 3.5 10 20 30 40 50 60 70 80 90 0 3.0 i oh =1.5a 2ex i oh =1.8a 1-2ex motor voltage: 24v vertical, independent, heat sink without fins natural convection motor: r=1.4 , l=1.6mh motor running motor hold state current
STK672-220-E no.7465-9/10 when operations of the mosfet built into stk672-2** seri es ics is turned off for constant current chopping, the i d signal falls like the waveform shown in the figure above. at this time, the output voltage, v ds , suddenly rises due to electromagnetic induction generated by the motor coil. in the case of voltage that rises suddenly , voltage is restricted by the mosfet v dss . voltage restriction by v dss results in a mosfet avalanche. during avalanche operations, i d flows and the instantaneous energy at this time, eavl1, is represented by equation (1). eavl1=v dss iavl 0.5 tavl ------------------------------------------- (1) v dss : v units, iavl: a units, tavl: sec units the coefficient 0.5 in equation (1) is a constant required to convert the iavl triangle wave to a square wave. during stk672-2** series operations, the waveforms in the figure above repeat due to the constant current chopping operation. the allowable avalanche energy, eavl, is therefore represented by equation (2) used to find the average power loss, pavl, during avalanche mode multiplied by the chopping frequency in equation (1). pavl=v dss iavl 0.5 tavl fc ------------------------------------------- (2) fc: hz units (fc is set to the pwm frequency of 50khz.) for v dss , iavl, and tavl, be sure to actually operate th e stk672-2** series and substitute values when operations are observed using an oscilloscope. ex. if v dss =110v, iavl=1a, tavl=0.2 s when using a STK672-220-E driver, the result is: pavl=110 1 0.5 0.2 10 -6 50 10 3 =0.55w v dss =110v is a value actually measured using an oscilloscope. the allowable loss range for the allowable avalanche ener gy value, pavl, is shown in the graph in figure 3. when examining the avalanche energy, be sure to actually drive a motor and observe the i d , v dss , and tavl waveforms during operation, and then check that the result of calculating equation (2) falls within the allowable range for avalanche operations. [i d and v dss operating waveforms in non-avalanche mode] although the waveforms during avalanche mode are given in figure 1, sometimes an avalanche does not result during actual operations. factors causing avalanche are listed below. ? poor coupling of the motor?s phase coils (electromagnetic coupling of a phase and ab phase, b phase and bb phase). ? increase in the lead inductance of the harness caused by the circuit pattern of the p.c. board and motor. ? increases in v dss , tavl, and iavl in figure 1 due to an increase in the supply voltage from 24v to 36v. if the factors above are negligible, the waveforms shown in figure 1 become waveforms without avalanche as shown in figure 2. under operations shown in figure 2, avalanche does not occur and there is no need to consider the allowable loss range of pavl shown in figure 3. figure 2 output current, i d , and voltage, v ds , waveforms 2 of the stk672-2** series when driving a 2-phase stepping motor with constant current chopping v ds i d itf02558 i oh : motor current peak value
STK672-220-E no.7465-10/10 figure 3 allowable loss range, pavl-i oh during STK672-220-E avalanche operations note: the operating conditions given above represent a loss when driving a 2-phase stepping motor with constant current chopping. because it is possible to apply 3w or more at i oh =0a, be sure to avoid using the mosfet body diode that is used to drive the motor as a zener diode. [smoke emission precuations] if any of the output pins 2, 3, 4, and 5 is held open, the electrical stress onto the driver due to the inductive energy accumulated in the motor could cause short-circuit follo wed by permanent damage to the internal mosfet. as a result, the STK672-220-E may give rise to emit smoke. ps 0 0.5 1.0 1.5 3.5 2.5 3.0 2.0 0.5 0 itf02619 3.5 2.5 3.0 2.0 1.5 1.0 pavl - i oh motor phase current, i oh - a average power loss in the avalanche state, pavl- w 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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