2-Phase Stepper Motor Unipolar Driver ICs

Transcription

1 -Phase Excitation SLA7MU/SLA79M/SMA7MU/SMA79M -Phase Stepper Motor Unipolar Driver ICs Absolute Maximum Ratings Ratings Parameter Symbol SLA7MU SLA79M SMA7MU SMA79M Units Motor supply voltage CC 46 FET Drain-Source voltage DSS Control supply voltage S 46 TTL input voltage IN 7 Reference voltage REF Output current IO.. A Power dissipation PD 4. (Without Heatsink) 4. (Without Heatsink) W PD 3 (TC= C) 8(TC= C) W Channel temperature Tch C Storage temperature Tstg 4 to C (Ta= C) Electrical Characteristics DC characteristics AC characteristics Ratings Parameter Symbol SLA7MU SLA79M SMA7MU SMA79M Units min typ max min typ max min typ max min typ max IS Control supply current ma Condition S=44 S=44 S=44 S=44 Control supply voltage S FET Drain-Source DSS voltage Condition S=44, IDSS= µa S=44, IDSS= µa S=44, IDSS= µa S=44, IDSS= µa FET ON voltage DS Condition ID=A, S=4 ID=A, S=4 ID=A, S=4 ID=A, S=4 IDSS FET drain leakage current Condition DSS=, S=44 DSS=, S=44 DSS=, S=44 DSS=, S=44 FET diode forward SD.... voltage Condition ID=A ID=A ID=A ID=A IIH Condition IH=.4, S=44 IH=.4, S=44 IH=.4, S=44 IH=.4, S=44 TTL input current IIL Condition IL=.4, S=44 IL=.4, S=44 IL=.4, S=44 IL=.4, S=44 IH TTL input voltage Condition ID=A ID=A ID=A ID=A (Active High) IL Condition DSS= DSS= DSS= DSS= IH TTL input voltage Condition DSS= DSS= DSS= DSS= (Active Low) IL Switching time Condition ID=A ID=A ID=A ID=A Tr.... Condition S=4, ID=.8A S=4, ID=A S=4, ID=.8A S=4, ID=A (Ta= C) Tstg µ s Condition S=4, ID=.8A S=4, ID=A S=4, ID=.8A S=4, ID=A Tf.... Condition S=4, ID=.8A S=4, ID=A S=4, ID=.8A S=4, ID=A ma µ A ma SLA7MU/SLA79M/SMA7MU/SMA79M

2 -Phase Stepper Motor Unipolar Driver ICs (-Phase Excitation) SLA7MU/SLA79M/SMA7MU/SMA79M Internal Block Diagram 6 8 INA S Reg Reg INB 4 pin 6pin pin pin, 6,, pin Description of pins Excitation input Active H Active L RSA 7 TDA REFA GNDA GNDB REFB TDB RSB 9 Diagram of Standard External Circuit (Recommended Circuit Constants) CC (46 max) Excitation signal time chart b () r3 tda C r4 tdb C r Open collector r TdA TdB 8 6 S INA INB RSA REFA REFB RSB GA GB C3 C4 Rs Rs r r6 4 INA INB clock 3 INA H H L L H H INB L H H L L H - phase excitation clock INA H H H H L L L L H H H H tda L L L H L L L H L L L H INB L L H H H H L L L L H H tdb L H L L L H L L L H L L tda and tdb are signals before the inverter stage. r : Ω r : Ω (R) r3 : 47kΩ r4 : 47kΩ r :.4kΩ r6 :.4kΩ C : 33 to pf C : 33 to pf C3 : pf C4 : pf Rs :.8Ω typ(7mu) ( to W) Ω typ(79m) 6 SLA7MU/SLA79M/SMA7MU/SMA79M

3 -Phase Stepper Motor Unipolar Driver ICs (-Phase Excitation) SLA7MU/SLA79M/SMA7MU/SMA79M External Dimensions SLA7MU/SLA79M (Unit: mm) φ 3. ±. 3 ±. 4.4 ±. 6.4 ±. φ 3. ± ±..7 ±. Epoxy resin package 6 ±. 3 ±. 9.9 ±..6.. Part No. Lot No. 4 P.3 ±.7 =8.4 ±.... R-End.4 ±. 6.7 ±. (3) ±.7 4 P.3 ±.4 =8.4 ± ± ±.6 7. ±.6 3 ±.6.6 ± ± ±. 3 3 Forming No. No.83 Forming No. No.8 External Dimensions SMA7MU/SMA79MA (Unit: mm) Epoxy resin package 3 ±. 4 ±.. ±.. ±. 8.max Lot No. Part No P.3 ±. 4= ±. 6.7 ±. (3) (9.7)... 4 ±.7 P.3 ±. 4=8.4.6 ±..6 ±.. ±. (.9) (7.) 3 ±.6.6 ±.6 (4.6) Forming No. No.4 Forming No. No. SLA7MU/SLA79M/SMA7MU/SMA79M 7

4 -Phase Stepper Motor Unipolar Driver ICs (-Phase Excitation) Application Notes SLA7MU/SLA79M/SMA7MU/SMA79M Determining the Output Current Fig. shows the waveform of the output current (motor coil current). The method of determining the peak value of the output current (IO) based on this waveform is shown below. (Parameters for determining the output current IO) b: Reference supply voltage r,r: oltage-divider resistors for the reference supply voltage RS: Current sense resistor () Normal rotation mode IO is determined as follows when current flows at the maximum level during motor rotation. (See Fig..) IO () Power down mode The circuit in Fig.3 (rx and Tr) is added in order to decrease the coil current. IO is then determined as follows. IOPD r b... () rr RS r(rrx) r rx Equation () can be modified to obtain equation to determine rx. rx= b r r Rs IOPD b... () RS Fig. 4 and show the graphs of equations () and () respectively. Fig. Waveform of coil current (Phase A excitation ON) Phase A Phase A Fig. Normal mode b( ) r6 r r 3,(3) r C3 7,(9) RS Fig. 3 Power down mode b( ) r6 r r 3,(3) IO Power down signal rx Tr r C3 7,(9) RS Fig. 4 Output current IO vs. Current sense resistor RS Fig. Output current IOPD vs. ariable current sense resistor rx 4. Output current IO (A) 3 r b IO= rr RS r=ω r=ω rx= b= Output current IOPD (A)... RS =.Ω RS =.8Ω RS =Ω IOPD= b r(rrx) RS r rx r=ω r=ω b= 3 4 Current sense resistor RS (Ω) ariable current sense resistor rx (Ω) (NOTE) Ringing noise is produced in the current sense resistor RS when the MOSFET is switched ON and OFF by chopping. This noise is also generated in feedback signals from RS which may therefore cause the comparator to malfunction. To prevent chopping malfunctions, r(r6) and C3(C4) are added to act as a noise filter. However, when the values of these constants are increased, the response from RS to the comparator becomes slow. Hence the value of the output current IO is somewhat higher than the calculated value. 8 SLA7MU/SLA79M/SMA7MU/SMA79M

5 f (khz) f (khz) -Phase Stepper Motor Unipolar Driver ICs (-Phase Excitation) SLA7MU/SLA79M/SMA7MU/SMA79M Determining the chopper frequency Fig. 6 Chopper frequency vs. Motor coil resistance Determining TOFF The SLA7M and SMA7M series are self-excited choppers. The chopping OFF time TOFF is fixed by r3/c and r4/c connected to terminal Td. TOFF can be calculated using the following formula: TOFF r3 C rn ( = r4 C rn ( ) b b The circuit constants and the TOFF value shown below are recommended. TOFF = µs at r3=47kω, C=pF, b= ON time TON ( µ s) CC =4 CC = Motor coil resistance Rm (Ω) Chopping frequency f (khz) r3 r4 C = C = 47kΩ pf TOFF = µ s RS =Ω Lm =~3ms Rm Chopper frequency vs. Supply voltage Chopper frequency vs. Output current Motor : 3LM-C IO =.8A at CC=4 RS=Ω 3 Motor : 3LM-C CC=4 RS=Ω 3 4 CC () IO (A) SLA7MU/SLA79M/SMA7MU/SMA79M 9

6 Case temperature rise TCa ( C) Case temperature rise TCa ( C) Case temperature rise TCa ( C) Case temperature rise TCa ( C) Heat dissipation per phase PH (W) -Phase Stepper Motor Unipolar Driver ICs (-Phase Excitation) SLA7MU/SLA79M/SMA7MU/SMA79M Thermal Design An outline of the method for calculating heat dissipation is shown below. ()Obtain the value of PH that corresponds to the motor coil current IO from Fig. 7 "Heat dissipation per phase PH vs. Output current IO." () The power dissipation Pdiss is obtained using the following formula. : Pdiss PH. S (W) - phase excitation: Pdiss 3 PH. S (W) (3)Obtain the temperature rise that corresponds to the calculated value of Pdiss from Fig. 8 "Temperature rise." Fig. 7 Heat dissipation per phase PH vs. Output current IO. SLA7MU, ASMA7MU. SLA79M, SMA79M CC = Output current IO (A) Motor : 3LM-C Heat dissipation per phase PH (W) CC = Output current IO (A) Motor : 3LM-C4 Fig. 8 Temperature rise SLA7M series SMA7M series Tj Tj Tja ( C) TCa TC Tja ( C) TCa TC 3 4 Total Power (W) 3 4 Total Power (W) Thermal characteristics 3 SLA7MU 3 SLA79M 3 Motor : PH6-B Motor current IO=.8A Ta= C CC=4, S=4 Motor : PH6-B Motor current IO=.8A Ta= C CC=4, S=4 K K 3 3 SMA7MU 3 SMA79MU Motor : PH6-B Motor current IO=.8A Ta= C CC=4, S=4 Motor : PH6-B Motor current IO=.8A Ta= C CC=4, S=4 K K SLA7MU/SLA79M/SMA7MU/SMA79M

7 Pull-out torque (kg-cm) Pull-out torque (kg-cm) Supply current ICC (ma) Supply current ICC (ma) -Phase Stepper Motor Unipolar Driver ICs (-Phase Excitation) SLA7MU/SLA79M/SMA7MU/SMA79M Supply oltage CC vs. Supply Current ICC SLA7MU, SMA7MU SLA79M, SMA79M IO=A Motor : 3LM-C -phase excitation IO : Output current 3 IO=A Motor : 3LM-C4 -phase excitation IO : Output current 3 4 Supply voltage CC ().4A.A 3 4 Supply voltage CC ().A.A Torque Characteristics. SLA7MU, SMA7MU. SLA79M, SMA79M... Motor : PX44- Output current IO =.6A Motor supply voltage CC =4. Motor : 3LM-C Output current IO =.8A Motor supply voltage CC =4.. K K K K SLA7MU/SLA79M/SMA7MU/SMA79M