Ordering number : EN4292A Thick Film Hybrid 1C No, 42924 If . STK6712BMK3 Unipolar Fixed-current Chopper-type 4-phase Stepping Motor Driver Overview Package Dimensions The STK6712BMK3 is a unipolar fixed-current unit: mm chopper-type 4-phase stepping motor driver hybrid IC (HIC)} which uses a MOSFET power device. The 4129 excitation sequence signal is active low. [STK67128MK3] Applications 33 * Serial printer, line printer, and laser beam printer (LBP) paper feed and carriage motor drivers 1 * PPC scanner and LBP paper feed drivers * XY plotter pen drivers + Industrial robot applications, etc. Features TTT TTT Th ] * Uses IMST (Insulated Metal Substrate Technology) of et substrate. * This IC is the same as the STK6712BMK2 without the regulator and with modifications to the MOSFET. ze 15X2,54038.1 Internal power dissipation has been cut by about 30%, and the external 2 W resistance is also unneeded. * Self-excitation design means chipping frequency is determined by motor L and R. Supports chopping at 20 kHz or higher. * Very low number of external components required. * Wide operating supply voltage range (Vccl = 18 to 42V) * Excitation sequence signal is active low, and is TTL level for direct interfacing to the microcomputer. + The unipolar design enables use as a driver for hybrid, PW, or VR type stepping motors, * Supports W1-2 phase operation, with a dual Vref pin. SANYO Electric Co., Ltd. Semiconductor Business Headquarters TOKYO OFFICE Tokyo Bldg, 1-10, 1 Chome, Ueno, Taito-ku, TOK YO JAPAN 52995HA (OT)/D0992Y0 No. 4292-1/10STK6712BMK3 Maximum Ratings at Ta = 25C Parameter Symbol Conditions Ratings Unit Maximum supply voltage 1 Veclmax No input signal 52 Vv Maximum supply voliage f Veelmax _ No input signal 2 Vv Maximum supply voltage 2 Veo2max No input signal 7 v Maximum phase current Toy max per phase, R/L =50, 10mH, 2.5 A 0.5 s 1 pulse, Vcc input Operating substrate temperature Tc max 105 Cc Junction temperature Tj max 150 C Storage temperature Tstg 40 to #125 C Repeated avalanche handling capability Ear max 38 mJ Allowable Operating Ranges at Ta = 25C Unit Supply voltage 1 Vecl With input signal 18 to 42 v Supply voltage 2 Ver2 With input signal 4.75 to 5.25 Vv Phase driver withstand voltage Voss (min)120 Vv Phase current Topy max Duty 50% (max)1.7 A Junctlon Thermal Resistance Unit Power FET 6j-c 13.5 Ch Electrical Characteristics at Ta = 25C, Veel = 36V, Vec2 = 5V min lyp max Unit Output saturation voltage 1 Ver Rp =230, Vye0.8V 11 1.5 Vv Output current (average) To ave R/L=3.5.0/3,8mH, Vpy=0.8, per phase 0.52 0.58 0.64 A Pin current consumption (average) lec2 Load, R=3.59, L=3.8mH 10 20 mA Vin = 0.89, per phase FET diode voltage Vdf Idf=1.0A 1.2 1.8 Vv TTL input ON voltage Vo Input voltage when Fl, 2,3, 4 OFF 2.0 v TTL input OFF voltage Van Input voltage when FI, 2, 3,4 ON 0.8 Vv Switching time ton Ry =24Q0, Vyy=O.8V 95 ns lorF Ry =242, Vy=0.8V 0.2 Hs Note: With regulated voltage power supply. Equivalent Circult veer A az sR g TH Wet NC Vret Ta? wa yg B B B PG SG 1 9a Ta Ts a Ya %o oe 91 fe Se fs % 46 . [5 | | 1 | | | FY F2 Fa FQ , Lo G2 i 66. | AN e) L ee | 162 HE vs he C2 | at [re | j Jatt AS RG . i | ia 4A te. pep HAe7ic Wer |_| -_ 6 x x pt : 0? i RT AB | ez vec! Sample Application Circult 18Vit042V 7 190u "3 Igy = 0.9A set constant aA rH ou 4-phase input wk rt ' eee ceee 0 ' held {Active Low) 25 : 1 A tee | julpul current waveform when phases he a . ars (locked) Sv Ne Tt? 9 Ayr vec 51K6712 rt 6.8k Rol OMxy BA ppg ta | oe lb | Jo. jlon Line ee eee i Toave Oly L 8 . JSuUUUU WU 4 we ET 4-phase stepping motor a (al 390) oF [3 L Measure output current values in this state PG | Unit (resistance:Q , capacitance:F) No. 4292-2/10STK6712BMK3 Note For reference, when Igy = 1.1 A, Ro, = 6.8 kQ and Rgg = 390 2. R Ion = K x 02 x Vec2/R7 Ro tRo2 Ke13 R7= Rg =.0.332 43% To reduce noise during motor hold, it is possible to mount Co, = 0.01 uF and Coz ~ 100 to 200 pF. Normally these are not required. Note Both input signals cannot be L at the same time. STK6712BMK3 Circuit Operation Vect Ton an - ec2 g Ort Rol Ro2 1ft AAN Ahh : | _ a 'R sR SATS Vref NC red Td2 g8 gB A B PG SG 1 2 13 5s D 8 91% 10 14 (16 1 6 4 5 o | 19 o Oo 9 2 0 oo Oo oO 20 0 A 1 I 1 1 1 ' { (any (23 er ! |r F4 F3 vot fd cl C2 > bn = t+ 3 Rae ry BARS \ Ic2 Oo Ra 12 h RI RY t = = 1 7 4 Lots = jn 8? Enc s IC2 +4 ct mT LT ty Ie2 i iC UW @ oe Jt l x, Ly eee <== = = h= R7/1 | RS Yoo} Fig. 1 STK6712BMK3 Internal Equivalent Circuit The operation for a 4-phase dual-excitation example is described below. The STK6712BMK3 equivalent circuit is given in Fig. 1. The circuit consists of the phase drivers, the comparator, the PWM excitation select and the current detect resistance. In Fig. 1 @A is input with low, and @A with high. When Q1 goes on, the +pin of IC1 (comparator) goes low, making IC1 output A low also. A winding current ipy through Q1 increases as: R _ -=t Vcc] VSAT (yg LS sssseceaceeeesesseervateenetessesitenissceantcnssreasaenaeenneeeunseeserente(1) ion = z L: motor winding inductance R: Sum of winding resistance and current detect resistance For this reason, pin voltage VR7 at source resistor R7 increases, and when the Vpo voltages of pin 8 and RO2 are equal output A goes high, and Q1 turns off. The inverse voltage VTP is as: Vop = Vref = <0 5) HK VCD vierissesssensnssnensccnsnravesaterssenansansseessessananensasansasasenenenasanecasasseas (2) In general stepping motor coils use BIFALAR windings, so the energy stored in L1 is generated by L2, at which time the current in L2 is iopr. igpp conduction continues until the charges of capacitors C1 and C2 on R3 and R4 pins (Ec) equal Vpq9. When they are equal, output A inverts and becomes low. Motor winding current ion again rises t0 Vpo2 level. This motor current on/off (constant current chopping) is repeated. This waveform is illustrated on the next page. No. 4292-3/10STK6712BMK3 voc lOFF ae <i I 25] I vez I | l ' ' , AB B1 ! 7 t + Sem ( 1 R2 @) 1 -__W---_ + IL Cl Vret Rg |S +-_{ >- | ANA 1| Rt TH STK6712BMK3 Basic Circuit Waveform Timing Charts C1 discharge voltage Ec Sane LALA PLE s=-" YoL Voc? ---- | ov ioFF L . OA 'ON VW --- 04 Fig-2 No. 4292-4/10STK6712BMK3 Control Logic Timing Chart a) 2-phase excitation b) 1-2 phase excitation Phase input Gate input Phase input Gate inpul CLOCK | > CLOCK P| P] Dl LL Gate input Phase input a,ao [> A8 ox [4 < COMP A,8 STK6712BMK3 Excitation Circuit No, 4292-5/10STK6712BMK3 Setting Output Current The motor output current waveform is shown to the right. 1H no Output current Igy, can be set by the user by adjusting the / | (| | voltage of pin 9 (11). OA The computation equation is indicated below. / J J | R Vref = 02 V2 rete ereercetrere tenes (3) Ro} + Rog Fig. 3 Output Motor Current Waveform Vref lon = K x Re seceennceeeesensecseennasesetanenssenasene(Q) ve? . STKGTIZBM Rg: Internal current detect resistance 6 (0.3343%) K: 1.1 to 1.2 (correction for actual measurement) Power down can be accomplished by reducing the synthetic impedance by connecting a resistance in parallel to Rgp. The motor output current variation range can be set for the Fig. 4 Vref Peripheral Circuit range of: Toy = 0.2A to L.7A but when set to Igy = 0.2 A or lower note that the HIC GND pattern will be one-point earth with respect to the power supply. If earth is poor, there may be no motor current when Ipy = 0.2 A. We recommend a motor inductance usage range of L = 1 mH to 10 mH. Determining Chopping Frequency The STK6712BMK3 uses constant current for self-excitation. The Ioy7 torr time is set to about 14 us, and the tox time can be expressed as: - & lOFF - R loFF L Vec-( Ion ~Yec+088 (l-e )) (R + 0.88) ton = Rr 088 In Veo= (R +088) lon - ) sreteneeetetereesennne (5) L: Motor winding inductance R: Motor resistance ~ Vcc: Motor supply voltage Ioq: Output current As a result, the chopping frequency is Fe ton tion = ton + ty 106 (Hz) sasssessssesesestessnessneesnensaecavessarersaneeseenseenesenssssestasessnssstseracerss (6) No. 4292-6/10STK6712BMK3 However, note that when the following conditions exist the value for F will change. Voc + 0.88 L 6 ott Te UA) ccrtecreuerereteecercersrepanapannersrerestuensvaresrerareneisarererssenstes 14 x 10*25% In ( lonXR + Voc + 088 ) = torF2 (7) torr = topg! + topr2 = 14 x 10% + torr .F= 1 (Hz) ssssssssssssssssssssseenssssssseecessssesesesecenseessensesessssansansnseseeatasasnensnsssssesssasssssssss (8) Ton + 14x 10% + topp2 Because the STK6712BMK3 is self-exciting there will be minor variation in motor inductance during motor revolution. Final design verification is required in an actual model. Thermal Radiation Design The HIC radiator plate size is dependent on the motor output current Igy(A), motor electrical characteristics, excitation mode, and excitation input signal clock frequency felock (Hz). The thermal resistance for the radiator can be determined from the following expression. Oca = tema (OCW) sevessssosesinsonssssunssnsecsesonsesesnsssssesssavaneseseunsusesseceesuneasaceesssssiaseneeeecessanea (9) Te max = HIC substrate temperature CC) Ta = set internal temperature (C) Pd = HIC internal mean power dissipation (W) With a 2.00 mm aluminum radiation plate, the required area can be determined from Fig. 6. Note that substrate temperature will vary widely with set internal air temperature, and therefore the rear side of the HIC (the aluminum plate side) must always be kept below the maximum temperature of 105C, 20 Pd -@c-a 100 S - @ta No fin , No fin 23.0 [PC/W] = 7 23.0 [PC/W] = Te max = 105C * 5 Perpendicular mount, i 16 |--+ i natural cooling * TemaxTa 6 3 a ca= __ (CW) @ & 2 \ 4, | Pe g 2 - t fy . VS % a +} =? g \ Sty 4 Re q i eng Ps 10 Ch ay g 8 NS 8 py, "a q Pe late (2 - TOSS EER asee b 4 PE fa Gos > is i 50C 2, yO 5 60C 3 ~ A} ms 2 eS a ae 40 7 ; 10 5 100 : > 7 000 IC internal mean power dissipation, Pd - W Radiator area, $cm? Fig-5 Fig-6 No. 4292-7/10STK6712BMK3 HIC Internal Mean Power Dissipation Pd The internal mean power dissipation of the STK6712BMK3 is primarily due to the current control device, the regenerating current diode, the current detect resistance and the predriver circuit. Loss in each excitation mode is: 2 phase excitation Pd2px = (Vst + Vaf) _Telgek Ioyt2 + feo lon (Vst x tl + Vdf x 13) BI oy t2 8 1-2 phase excitation Pdl 2px = (Vst + Vdf) felock + Fou fclock (Vst x tl + Vdf x (3) Vst : Roy voltage drop + R7 (R8) output voltage Vdf : FET internal diode + R7 (R8) output voltage flock ; Input clock (reference frequency before frequency divider) tl, 12 and 3 are the time modes for the waveform indicated below. tL : Time for winding current to rise to set current 12 : Time for constant current chopping region B : Time from end of phase input signal until inverse current regeneration is complete. {ft ARETE . ' t i 12 13 Fig. 7 Motor Output Current Waveform (model) -L Rone In(1 _R+0.88 Tyg) vwreneeseesessssseecscnsensceconnsnssssesscecunsessessanavssesnsnsceassnacesssssesessssseeeessasee( JQ) tl = Voc Vec + 0.88 Be In ( Ion ' R+ Voc + 0.88 sroseeeeeerssensessoses( 13) Vec: Motor supply voltage (V) L: Motor inductance (H) R: Motor internal resistance (2) Toy: Motor output current peak (A) The chopping frequency F and 2 for each excitation mode are: 3 phase excitation F= fclock/?, v= (1/F) _ (t1 + 3) been ered erase ee eeanUSHG SG Lede ndGdEdE TOTO GSEIG HEBD ESIGEAGASEGEIEG GS RSE FLEES RT RSEDS (14) 1-2 phase excitation F = 3fclock/8, t2 = (1/F) th eecseessessesscsesserenerauacausnesesesesrsersnsesersannaniseeuanrarscenarsarsnesavenes (15) fclock : 4-phase divider input oscillation frequency The characteristic diagrams (typ) for Ipyq and Vst, and Ioyy and Vdf are given in Figs. 8 and 9. No, 4292-8/10STK6712BMK3 2 Fig-8. Vst - lo 20 Fig-9. Vdf - lo ie Lo s / . J J 74 : J / pd . [ / 0 0.4 0.8 1,2 1.6 z.0 o 04 0.8 1.2 1.6 2.0 Output saturation voltage, Vst - FET diode voltage, Vdf - V Output current, Io A Output current, Io A STK6712BMK3 No Thermal Radiation Range (example) An example of STK6712BMK3 use in the no-fin state is indicated below. Conditions: * Motor supply voltage Vocl = 30 V, stepping motor: Electrical characteristics 3.5mH/@, 3.5Q/ - Excitation: 2-phase , * Input clock frequency 500Hz = fclock HIC ambient temperature Ta = 25C, natural convection * HIC rear substrate temperature Tc = 105C, saturation * Motor output current Ip = 1.4A At this time, the HIC permissible loss can be calculated as: , wm Fe MAX =TA _ LOS 25g Ay) cresescsssesssescsesnssvecsensvessensasecensnsssessesssenssssenses Maximum loss: Pd max = tc a a =3-4(0W) (16) From these conditions and expressions (12), (13) and (14): t] = 0.183ms 12 = 3.670ms 13 = 0.147ms Vst and Vdf can be determined from Fig. 8, Fig. 9 and expression (10) as: Pd2ex = (Vst + Vdf} fog Iput2 + Felnek. Togy (VSL tL + VE x 13) vresrersesesseresenersenensseneonsseeasnentaees (17) = 3.08 + 0.14 = 3.22 (W) From expression (9), Tc is calculated as: Te = Pd2py X OC a + Ta = 3.22 X 23 + 25 = 99.1 (OC) wrereerensercrstsresnensastesconasneseaneceanneesenasersnnsesssveessnrenssasnes sees (18) This is only one example, and because convection and other air movements around the HIC will not match mathematical modelling verification with an actual model is essential. No. 4292-9/10STK6712BMK3 Motor Hold Noise Countermeasures The STK6712BMK3 executes constant current chopping outside the audible range. During motor hold the current hold is outside the range of audible frequencies, but for motors of sizes 30 to 40 mm square (when scen from the shaft direction) with inductance of about 15 mH, there are cases where the output noise is converted to low-frequency noise. In this case, addition of the following components will essentially eliminate such audible noisc. | 8 Cxt L 100 to 200 p 10 vee2 Hy) wl STK6712BMK3 68k | | a } 5 ___Wi_+ Ry I} 1! Cx 0.01 to 0.1 Unit (resistance: , capacitance:F) Fig. 10 Motor Hold Noise Countermeasure Wi No products described or contained herein are intended for use in surgical implants, life-support systems, aerospace equipment, nuclear power control systems, vehicles, disaster/crime-prevention equipment and the like, the failure of which may directly or indirectly cause injury, death or property loss. Hf Anyone purchasing any products described or contained herein for an above-mentioned use shall: @ Accept full responsibility and indemnify and defend SANYO ELECTRIC Co., LTO., its affiliates, subsidiaries and distributors and all their officers and employees, jointly and severally, against any and all claims and litigation and all damages, cost and expenses associated with such use: @ Not impose any responsibility for any fault or negligence which may be cited in any such claim or litigation on SANYO ELECTRIC CO., LTD., its affiliates, subsidiaries and distributors or any of their officers and employees jointly or severally. Mf Information (including circuit diagrams and circuit parameters) herein is for example only; it is not guaranteed for volume production. SANYO believes information herein is accurate and reliable, but no guarantees are made or implied regarding its use or any infringements of intellectual property rights or other rights of third parties. This catalog provides information as of May, 1995. Specifications and information herein are subject to change without notice. No. 4292-10/10