"00 WED 15:31 FAX 01189776095 GOTHIC CRELLON s34u ic NJM3770A a VIS LOA input, limited microstepping can be achieved. Sensor resistor The R, resistor should be of a noninduc- tive type power resistor. A 0.5 ohm resletor, tolerance < 1%, is a good choica for 800 mA max moter current at Vp = SV. The peak motor current, i, Can be calculated by using the formula: in = (V_* 0.080) /R, [A], at 100% level External recirculation diodes Recirculation diodes must be connected across each motor terminal and the supply voltage, V,,,. The anodes shall be connected to the motor terminals and the cathodes to tha V,,, voltage Ultra. fast recovery diodes should be used for inaximum performance and reliability, The Specifications on this databook are onty givan for Information , without any guarantee aS regards either mistakes or omissions. The application cireuits In this databook are described only to show representattve usages of the product and not intended for the guarantee or permission of any right including tha industrial rights. Pp (W) Bp (Ww) N I a0 40 4 25 NS Se 20 a0 F- ON: at 1.5 20 Ye, Sigh LAST TT] De 10 - | | SN 5 Sa N | 4 15 a 30 150 lw (A) Tamb (C} motor current Figure 12 Typleal power dissipation vs, Figure 13. Allowable power dissipation Vs. ambient temperature fi sprrceat [iat piesa leh HL ay coated ee a WTC euegreureribe rise pate ae gy Ted ptt Bed | {aH ee ae a rap atta sal ape ie ITH i leu last ma eT te : maT Ustad leaden! : rants ree arent alt yeayteta ls 5 mein NTH Viet TP clcmeetarejsnlacversel jira wr itt ts a Beer acre Eh arid Le i 5 D) 6 D % wm 35 PCB copper toil area [cm2] srmePLCC package Figure 15. Copper foil used as a heatsink28/06 '00 WED 15:32 FAX 01189776095 GOTHIC CRELLON 1003 NJM3770A Figure 8. Typical stepper motor dnver application with NJM2770A @ TYPICAL CHARACTERISTICS 9 1 & 12 (4 Figure 9. Typical source saturation vs output current 2 tus Figure 10. Typical sink saturation vs. output current Figure 11. Typical lower diode voltage drop vs. recirculating current Some stepper motors have such high core losses that they are not sulted for switched-made operation, interference As the circuit operates with switched- mode current regulation, interferance- generation problems can arise in some applications A good measure is then to decouple the circuit with a 0.1 WF ceramic capacitor, located near the Package across the power line V,_, and ground. Alzo make sure that the V__ Input is sufficiently decoupled. An electrolyte capacitor should be used in the +5 V rail, close to the circuit New Japan Radio Co. Lhd. The ground leads between R,, Cand circuit GND should be kept 95 short as possible. This applles also to tha leads connecting R, and R, to pin 16 and pin 10 respectively In order to minimize alectromagnetic interference, It is recommended to route M, and M, leads in parael on the printed circuit board directly to the tarminal connector. The motor wiras should be twisted in pairs, each phase separately, when instafiing the motor system. Unused inputs Unused inputs should be connected to proper voltage levels In order to obtain the highest possibie nolse immunity. Ramping A stepper motor is a synchronous motor and does not change Its spead due to load variations. This means that the torque of the motor must be large enough to match the combined inertia of the motor and load for ail operation modes. At speed changes, the requiras torque Increases by the square, and the required power by the cube of the spead change. Ramping, i e., controted accaleration or deceleraton must then be considered to avoid motor pull-out, Vous Vue The supply voltages, V_, and V,,,, can be tumed on or off In any order. Normal dv/dt valuas are assumed. Before a driver circuit board is removed from its system, al supply voltages must be tumed aff to avoid destructive transients being generated by the motor. Switching frequency The motor inductance, together with the pulse time, (,, determines the switching fraquency of the currant regulator. The choice of motor may then require other values on the R,, C_, components than those recommended in figure 6, to obtain a switching frequericy above the audible range. Switching frequencies above 40 KHz are not recommended because the current regulation can be affected, Analog contro! As the current levels can be continu- ously controlled by modutating the V,,28/06 "00 WED 15:32 FAX 01189776095 GOTHIC CRELLON NJM3770A the current has decayed and the analog voltage across the sensing resistor is below the comparator threshold level, Tha sinking transistor then tums on and the motor current starts to increase agaln, The cycie is repeated until the current is turned off via the logic inputs. When both |, and 1, are high, afl four transistors In the output H-bridge are turned off, which means that inductive Current recirculates through two opposite free-whealing diodes (see figura 6, arrow 3). this method of tuming off the currant results in a faster currant decay than if only one transistor was tumed off and will therefore improve speed perfor- mance In half-stepping mode. Heatsinking The junction temperature of the chip highty effects the lifatime of the circuit tn high-currant applications, the heatsinking must be carefully consid- erad The Rth,, of the NJM3770A can be reduced by soldering the ground pins to @ Suitable copper ground plane on the printed circuit board (sae figure 14) or by applying an external heatsink type V7 or V8, see figure 14, The diagram in figure 13 shows tha mMaximurn permissible power dissipation versus the ambient temperature in C, tor heatsinks of the type V7, V8, or a 20 cm copper area respectively. Any extemal heatsink or printed elrcuit board Copper must be connected to electrical ground For motor currents higher than approx 600 mA, some form of heatsinking Is recommended to assure optimal reliability. The diagrams in figures 12 and 13 can be used to determine the required haatsinking of the circuit. In some systems, forced-air coollng may be available to reduce the temperature tise of the circuit. PLICATI INFOR- mf Are ONS INFOR Motor selection Some stepper motors are not designed for continuous operation at maximum current As the circuit drives a constant current through the motor, its tempera- ture can increase, both at low- and high- speed operation. odes Figure 5. Motor current (ly). Vertical : 200 mA/div, Horizontal: 1 ms/div, expandad part 100 ps/div. Figure 6 Output stage with current paths for fast and slow current decay a co | eee 1, f+-_ rc rm _. ont ll 71 my I. a PW) te f [ Cc __ i. + , mM Cc ~ Va 100% 4 = | | CTT 1 | pu ~100% \ 100% r = I LOE Full step position femme Half stap positon Se Bran by mod Hal step made af 100% Ful siep mode ac 60 % Figure 7 Principal operating sequence, New Japan Radio Co,Lhd. Moo28/06 '00 WED 15:33 FAX 01189776095 GOTHIC CRELLON [41005 NJM3770A a EUNCTIONAL DESCRIP- I Vaa=Vu | The NJM3770A is intended to drive a Nomnafiead bipolar constant current through one 1 winding of a 2-phase steppar motor. e fr | low Current contro! is achieved through switched-mode regulation, see figure 5 and 6, Three diferent current levels and zero current can be selected by the input logic, The elrevit contains the following functional blocks: * Input logic * Currant sense + Singie-pulse generator * Output stage input logic Phase Input. The phase input deter- mines the direction of the current in the motor winding. High input forces the cutrent from terminal M, to M,, and faw input from terminal M, to M,. A Schmitt trigger provides noise immunity and a delay circuit ellminates the nsk of cross conduction in the output stage dunng a phase shift. Half and full-step operation is Possible. Current level selection. The status of I, and |, inputs determines the current level in the motor winding. Three fixed current levels can be selected according to the table below. Motor current High level 100% Medium level 60% Low levet 20% Zero current 0% H OH Tha specific values of the diffarant currant levels are datermined by the reference voitage V, together with the value of the sensing resistor R,. Tha peak motor current can be calculated as follows: i, = (V,* 0.080) /R, [A], at 100% level The moter currant can also be Continuously varied by modulating the voltage reference input. Current sensor The current sensor contains q reference Voltage divider and three compsrators for measuring each of the selectable rriers ier e > Ve ett Vou Vow Vou > 1 -__'n ton * bog D= ton * tow Figure 4, Definition of terms current levels The motor currant is See figures and6 =8N66d a5 a Voltage drop across the Overtoad protectian current sensing resistor, R,, and : . compared Wiles of he %, The circult is equipped with a thermal references from the divider. When the fwo voltages ara equal, the comperator triggers the single-pulse generator Only on@ Comparator at 6 time is activated by the input logic. Singie-putse generator The puise generator Is a monostabie mulbvibrator tnggered on the positive edge of the comparator output. The thultivibrator output is high during the pulse time, ta Which is determined by the timing components R, and C,. tar = 0.69*R, C, The single pulse switches off the Power feed to the mator winding, causing the winding to dacrease during tee tf 8 New tagger signal should occur dunng t,,. itis ignored Output stage The output stage contains four transis tors and two diodes, connectad in an H- bndge. Note that the uppet recirculation diodes are connacted to the circuit xtamally The two sinking transistors are usad to switch the power suppiled to the motor winding, thus dnving a constant current through the winding New Japan Radio Co,Ltd shutdown function, which will limit the Junction temperature. The Output current will be reduced if the maximum permis- sible junction temperature is axceeded. it should be noted, however, that It is not short circult protected, Operation When a voltage Vie, IS Applied across the motor winding, the current rise follows the equation: i, = Va, / R)*(1- 9 tyfky Winding resistance Winding inductance = time (see figura 6, arrow 1) The motor curtent sppaars across the extemal sensing resistor, R,, as an Aahalog voltage. This voltage is fed through a low-pass filter, R,C,, to the voltage comparator Input (pin 10). At the moment the sansed voltage nses above the comparator threshold valtage, the monostable Is triggered and Its output tums off the conducting eink translator, The polarity across the motor winding revarses and the current is forced to crculate through the appropriate upper Protection diode back through the sourca transistor (see figure 6, arrow 2). After the monostable has timed out, R Le t28/06 '00 WED 15:33 FAX 01189776095 GOTHIC CRELLON 006 NJM3770A @ PIN CONFIGURATIONS Mp [1 WY iG E T {2 hs} Ma Vem [3] na] Vem GND [4] NIM ig) GND 3770AD3 GND [5 12; GND Voc (6! ni VR i Ho} C Phase [3] 3] to Figure 3. Pin configurations @ PIN DESCRIPTION emp DIP. PLCC Symbot | Description 4 1 10 Ms Motor output B, Motor current flows from M |, to M, when Phase is high. 2 2 1 T Clock oscillator. Timing pin connect a 56 kQ resistor and a 820 pF in parallel between T and Ground 3 3,14 12,4 Viens Motor supply voltage, 10 to 40 V. Pin 3(12) and pin 14(4) should be wired together 4-7, 4,5, 1-3,9, GND | Ground and negative supply Note these pins are used for heatsinking. 14-16 12,13 13-17,28 Make sure that all ground pina are soldered onto 4 sultable large copper ground plane for efficient heat sinking. 8 6 18 Vee Logic Voltage supply normally +5 V. 9 7 19 1, Logic input It controls, together wrth the 10 input, the current level in the output stage The controllable levels are fixed to 100, 60, 20, 0%. 10 8 20 Phase Controls the direction of the motor current of M, and M,, outputs Motor current flows from M, to M, whan the phase input is high 11 9 21 \, Logic input it controls, together with the |, input, the currant feval in the output stage The controllable levels are fixed to 100, 60, 20, 0% 12 10 23 Cc Comparator Input, This input senses the instantaneous voltage across tha sensing resistor, fillered through a RC Network. 13 11 24 Ve Reference voltage. Controls the threshold voltage of the comparator and hence the output currant. Input resistance: typically 6.8 kQ + 20%. 19 15 6 M, Motor output A, Motor current flows from M, to M, when Phase ts high 20 16 & E Common emitter, Connect the Sense resistor between this pin and ground. New Japan Radio Co.Lhd.28/06 "00 WED 15:33 FAX 01189776095 NJM3770A ELECTRICAL CHARACTERISTICS Electrical characteristes over recommended operating conditions. C, GOTHIC CRELLON = 820 pF, R, = 56 kohm Parameter Symbol Conditions Min Typ Max Unk General Supply current Isc Vin = 20 to 40 V, 1, =i, = HIGH, - 30 40 | mA View = 20 to 40 V. 1, = 1, = LOW, - 48 65 mA _.= 23 kHz Total power dissipation P, f, = 28 kHz, |= 1000 mA, V,, = 36 V - 79 23, WwW Note 2, 4 f, = 24 kHz, lw = 1000 mA V,..5 12 V - 17 21 Ww Note 2, 4, f, = 28 kHz, | = 1300 mA, V,., = 36V - 27 3.2 WwW Note 3, 4 #, = 28 kHz, |,,= 1500 MA, V = 36 V - 35] - w Note 3, 4 Tum-off delay t, T, = +25C, dV./dt 2 50 mV/us - 2.5 us Thermal shutdown junction temperature - 170 - C Logic Inputs Logic HIGH input voltage Via 2.0 : - Vv Logie LOW Input voltage Vv - - 0.8 v Logic HIGH input current la Vi=zav = 20 pA Logic LOW input current 4 V=04V -0.4 - - mA Analog Inputs Comparator threshold vaitage Vou | Va=5.0V,1,=f = LOW 400 415[ 430[ mv Comparator threshold Vollage Vow Va = 50 V, i, HIGH, 1, = LOW 240 250 265; mv Comparator threshold volfage Ve V,=50 V1, = LOW, 1 =HIGG 70 80 90 mV Input current I. -20 . - HA Motor Outputs Lower transistor Saturation voltage |, 7 1.0A - os/ a8] i,2 13A - 0.8 1a] Vv Lowr diode forward voltage drop (= 1.0A T3 1.6 V 1, = 1.34 - 15 18, oV Upper transistor saturation voltage 1, = 1.04 - 1.1 1.3 v = 13a - 13 16] Vv Output leakage current =), = HIGH, T= +25C - 5 100 | pA Monostable Cut off ime ter Veu= 10 V, b> 5 ps 27 Ry 35 7 ous i THERMAL CHARACTERISTICS Parameter Symbol Canditions Min Typ Max Unit Thermal rasistance Rth .. | DIP package . 11 - CAW Rth,, | DIP package. Note 2. 40 - "CAV - Rth,. | PLCC packege . 9 - CW Rth,, [PLCC package Note 2. - 35 - CAV __ Rth,,. [ EMP package. 11 - Cw Rth., | EMP package, . 40 - *CiW Notes 1 All voltages are with respect to ground, 2. All ground pins soldered onto a 20 cm? 4. Not covered by final test program Currents are positive into, negative out of specified tarminal PCB copper area with free alr convection Ta=4+26C 3. DIP package with extemal heatsink (Staver V7) and minimal copper area. Typical Rth,, = 27.5C/w. T, = +28C New Japan Radio Co,Ltd. 10071008 28/06 00 WED 15:33 FAX 01189776095 GOTHIC CRELLON NJM3770A SS ay a a sieaeensieae, @ ABSOLUTE MAXIMUM RATINGS Parameter Pin no. [DIP package) Symbol Min Max Unit Voltage _Logic supply 6 View 0 7 Vv Motor supply 3,14 Vina 0 45 Vv Logic inputs 7,8,9 V, 03 6 Vv Comparator Input 10 Ve 0.3 Ver Vv Reference input 11 Vv, -03 15 Vv Current Motor output current 1,15 la +1800 +1800 mA Logie inputs 7,8,9 t 10 - mA Analog inputs 10,11 I, -10 . mA Temperature Operating junction temperature Ty -40 +150 C Storage temperature T, 55 +180 C MM RECOMMENDED OPERATING CONDITIONS Parameter Symbol Min Typ Max Unit Logic supply voltage Ven 4.75 5 5.25 Vv Motor supply voltage View 10 - 40 Vv __ Motor output current ly -1500 - +1500 mA Junction temperature T, -20 - #125 *C Rise tme logic inputs t - - 2 ys Fall time iogic inputs t - - 2 ws rr hae Yoo Viet Ving Wn ty Freee fy m = : or Lh | ifaw te ti 7 J wate I | Me bk Ya : + {Ho dent Bags Yee % a . t vu Vie py v v k a a Bram, ow Jz Cure Bates ie. 3 n MIMST7OA Ig Te 1 F ly 1h Yo | , Ye Pia no. refers | eae ar ou opr 16 DIP-packago I y Ry Figure 2. Definition of symbols21009 28/06 '00 WED 15:34 FAX 01189776095 GOTHIC CRELLON NJM3770A STEPPER MOTOR DRIVER l@ GENERAL DESCRIPTION @ PACKAGE OUTLINE NJM3770A is a stepper motor dnver, which consists of a LS-TTL compatible logic input stage, a current sensor, a monostable multvibrator and a high power H-bridge output stage. The NJM3770A is a high power version and pin-compatible with the NJM43717. Two NJM3770A and 3 small number of axternal components form 8 complete control and drive unit stepper motor systems. @ FEATURES * Half-step and full-step operation * Switched mode bipolar constant current drive * Wide range of current contro! 5 -1800 mA + While voltage range 10-45 V * Thermal overload protection * Packages DIP16 (Batwing) / PLCC28 / EMP20 @ BLOCK DIAGRAM l 24h : Ty &] (at Le] [& ody oe Ma Tt <i f # ls | -_|" Duden Btage iS -(| Mncstabie tae = on "Ry? Gg ena I Currant Sensor i 4 NJM3770A c T E Figure 1. Block diagram New Japan Radio Co. Lhd.