Unipolar Stepping Motor Drive Circuit Simulation
PSpice Version
VCC VCC VCC VCC
CLK
D1 Vcc
R1 U9 DIODE 12
CLK
1k FA S1 A A B
FA
+ +
0 U5
- - RON = {RON} Acom Bcom 0
/FA S
AND REF
+ 0 /A /B
/FB
- +
- U1
UNI-POLAR_STEP_MOTR
FB FB.
VCC L = 2.5M
HY S_I-CTRL R = 4.2
U10 VHY S = {VHY S} D2
1-PHASE U8 I_SET = {I_SET} DIODE
PPS = 100 /FA S2 /A
+ +
- -
U4 RON = {RON}
S
AND REF
+ 0
- +
-
FB.
VCC
HY S_I-CTRL
VHY S = {VHY S} D3
U7 I_SET = {I_SET} DIODE
/FB S3 /B
+ +
- -
U3 RON = {RON}
S
AND REF
+ 0
- +
-
FB.
VCC
HY S_I-CTRL
VHY S = {VHY S} D4
U6 I_SET = {I_SET} DIODE
FB S4 B
+ +
U2
- - RON = {RON}
S
AND REF
+ 0
- +
-
FB.
HY S_I-CTRL
VHY S = {VHY S}
PARAMETERS: I_SET = {I_SET} PARAMETERS:
I_SET = 0.5 RON = 10m
VHY S = 0.1
All Rights Reserved Copyright (C) Bee Technologies Corporation 2011 1

Unipolar Stepping Motor Drive Circuit
Contents
1. Concept of Simulation
2. Unipolar Stepping Motor Drive Circuit
3. Unipolar Stepping Motor
4. Switches
5. Signal Generator
6. Hysteresis-Based Current Controller
7. Unipolar Stepping Motor Drive Circuit (Example)
7.1 One-Phase Sequence Drive, IPHASE=0.5A, IRIPPLE=0.1A
7.2 Two-Phase Sequence Drive, IPHASE=0.5A, IRIPPLE=0.1A
7.3 Half-Phase Sequence Drive, IPHASE=0.5A, IRIPPLE=0.1A
8. Drive Circuit Efficiency
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1.Concept of Simulation
Block Diagram:
Control Unit Driver Unit: Switches Stepping
(e.g. Microcontroller)
(e.g. Hysteresis- (e.g. FET, Motor
Based Controller) Diode)
Sequence:
Parameter:
• One-Phase
Parameter: Parameter: •L
• Two-Phase
• I_SET • Ron •R
• Half-Step
• HYS
Models:
U2 VCC
CLK CLK CLK
FA FA FA FA
Ctrl_A A B
D1
DIODE
/FA /FA /FA
AND
U1 S1 Acom Bcom
Ctrl_A + + A
/FB /FB /FB REF
+ - - RON = 10m
S
/A /B
FB FB FB - +
-
U?
U? U? U?
FB. 0 UNI-POLAR_STEP_MOTR
1-PHASE 2-PHASE HALF-STEP HY S_I-CTRL L = 2.5M
PPS = 100 PPS = 100 PPS = 100 VHY S = {VHY S} R = 4.2
I_SET = {I_SET}
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2.Unipolar Stepping Motor Drive Circuit
Signal generator Hysteresis Based Current Switches Unipolar Stepping Motor Supply Voltage
CLK
Controller VCC VCC VCC VCC
D1 Vcc
R1 U9 DIODE 12
CLK
1k FA S1 A A B
FA
+ +
0 U5
- - RON = {RON} Acom Bcom 0
/FA S
AND REF
+ 0 /A /B
/FB
- +
- U1
UNI-POLAR_STEP_MOTR
FB FB.
VCC L = 2.5M
HY S_I-CTRL R = 4.2
U10 VHY S = {VHY S} D2
1-PHASE U8 I_SET = {I_SET} DIODE
PPS = 100 /FA S2 /A
+ +
- -
U4 RON = {RON}
S
AND REF
+ 0
- +
-
FB.
VCC
HY S_I-CTRL
VHY S = {VHY S} D3
U7 I_SET = {I_SET} DIODE
/FB S3 /B
+ +
- -
U3 RON = {RON}
S
AND REF
+ 0
- +
-
FB.
VCC
HY S_I-CTRL
VHY S = {VHY S} D4
U6 I_SET = {I_SET} DIODE
FB S4 B
+ +
U2
- - RON = {RON}
S
AND REF
+ 0
- +
-
FB.
HY S_I-CTRL
VHY S = {VHY S}
PARAMETERS: I_SET = {I_SET} PARAMETERS:
I_SET = 0.5 RON = 10m
VHY S = 0.1
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3.Unipolar Stepping Motor
A B • The electrical equivalent circuit of each phase consists
of an inductance of the phase winding series with
Acom Bcom resistance.
/A /B • The inductance is ideal (without saturation
U1
characteristics and the mutual inductance between
UNI-POLAR_STEP_MOTR phases)
L = 2.5M
R = 4.2 • The motor back EMF is set as zero to simplified the
model parameters extraction.
Input the inductance and resistance values (parameter: L, R) of the
stepping motor, that are usually provided by the manufacturer datasheet,
to generally model the phase winding.
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4.Switches
VCC
• A near-ideal DIODE can be modeled by using spice
D1
primitive model (D), which parameter: N=0.01
DIODE
RS=0.
S1
Ctrl_A + + A
- - RON = 10m
S • A near-ideal MOSFET can be modeled by using
0
PSpice VSWITCH that is voltage controlled switch.
The parameter RON represents Rds(on) characteristics of
MOSFET, that are usually provide by the manufacturer datasheet.
The value could be about 10m to 10 ohm.
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5.Signal Generator
The signal generators are used as a microcontroller capable of generating step pulses
and direction signals for the driver.
There are 3 useful stepping sequences to control unipolar stepping motor
One-Phase (Wave Drive)
CLK
FA
CLK
FA
CLK
FA • Consumes the least power.
/FA /FA /FA
• Assures the accuracy regardless of the winding imbalance.
/FB /FB /FB
FB FB FB
Two-Phase (Hi-Torque)
U? U? U?
• Energizes 2 phases at the same time.
1-PHASE 2-PHASE HALF-STEP
PPS = 100 PPS = 100 PPS = 100 • Offers an improved torque-speed result and greater holding torque.
Input PPS (Pulse Per Second) as a clock pulse speed(frequency).
Half-Step
• Doubles the stepping resolution of the motor.
• Reduces motor resonance which could cause a motor to stall at a resonant frequency.
• Please note that this sequence is 8 steps.
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5.1 One-Phase Sequence
5.0V
Clock
2.5V
0V
V(CLK)
5.0V
Phase A2.5V
ON
0V
V(FA)
5.0V
Phase /A
2.5V
ON
0V
V(/FA)
5.0V
Phase B2.5V ON
0V
V(FB)
5.0V
Phase /B
SEL>> ON
0V
0s 40ms 80ms
V(/FB)
1 Sequence Time
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5.2 Two-Phase Sequence
5.0V
Clock
2.5V
0V
V(CLK)
5.0V
Phase A2.5V
ON
0V
V(FA)
5.0V
Phase /A
2.5V
ON
0V
V(/FA)
5.0V
Phase B2.5V ON
0V
V(FB)
5.0V
Phase /B
SEL>> ON ON
0V
0s 40ms 80ms
V(/FB)
1 Sequence Time
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5.3 Half-Step Sequence
Clock 4.0V
2.0V
0V
V(CLK)
5.0V
Phase A2.5V
ON
0V
V(FA)
5.0V
Phase /A
2.5V
ON
0V
V(/FA)
5.0V
Phase B2.5V ON
0V
V(FB)
5.0V
Phase /B
SEL>> ON
0V
0s 80ms 160ms
V(/FB)
1 Sequence Time
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6.Hysteresis-Based Current Controller
U2
FA • Controlled by the signal from the
Ctrl_A
microcontroller.
AND
U1
• Generate the switch (MOSFET) drive signal
REF
+
- +
-
by comparing the measured phase current
FB. with their references.
HY S_I-CTRL
VHY S = 0.1
I_SET = 0.5
Input the reference value at the I_SET (e.g. I_SET=0.5A)
to set the regulated current level. The hysteresis
current value is set at the VHYS (e.g. VHYS=0.1A).
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7.1 One-Phase Sequence Drive, IPHASE=0.5A, IRIPPLE=0.1A
VCC VCC VCC VCC
CLK
D1 Vcc
R1 U9 DIODE 12
CLK
1k FA S1 A A B
FA
+ +
0 U5
- - RON = {RON} Acom Bcom 0
/FA S
AND REF
+ 0 /A /B
/FB
- +
- U1
UNI-POLAR_STEP_MOTR
FB FB.
VCC L = 2.5M
HY S_I-CTRL R = 4.2
U10 VHY S = {VHY S} D2
1-PHASE U8 I_SET = {I_SET} DIODE
PPS = 100 /FA S2 /A
+ +
- -
U4 RON = {RON}
S
One-Phase AND
+
REF
0
Step Sequence - +
Generator (100
-
FB.
VCC
pps) HY S_I-CTRL
VHY S = {VHY S} D3
U7 I_SET = {I_SET} DIODE
/FB S3 /B
+ +
- -
U3 RON = {RON}
S
AND REF
+ 0
- +
-
FB.
VCC
HY S_I-CTRL
VHY S = {VHY S} D4
U6 I_SET = {I_SET} DIODE
FB S4 B
+ +
U2
- - RON = {RON}
S
AND REF
+ 0
- +
-
FB.
HY S_I-CTRL
VHY S = {VHY S} *Analysis directives:
PARAMETERS: I_SET = {I_SET} PARAMETERS:
I_SET = 0.5
VHY S = 0.1
RON = 10m .TRAN 0 40ms 0 10u
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7.1 One-Phase Sequence Drive, IPHASE=0.5A, IRIPPLE=0.1A
5.0V
Clock
2.5V
0V
V(CLK)
5.0V 1.0A
1 2 Phase A Current I_HYS=0.1A
2.5V 0.5A
>> I_SET=0.5A
0V 0A
1 V(FA) 2 -I(U1:A)
5.0V 1.0A
1 2 Phase /A Current
2.5V 0.5A
>>
0V 0A
1 V(/FA) 2 -I(U1:/A)
5.0V 1.0A
1 2
Phase B Current
2.5V 0.5A
>>
0V 0A
1 V(FB) 2 -I(U1:B)
5.0V 1.0A
1 2 Phase /B Current
2.5V 0.5A
SEL>>
0V 0A
0s 10ms 20ms 30ms 40ms
1 V(/FB) 2 -I(U1:/B)
Time
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7.2 Two-Phase Sequence Drive, IPHASE=0.5A, IRIPPLE=0.1A
VCC VCC VCC VCC
CLK
D1 Vcc
R1 U9 DIODE 12
CLK
1k FA S1 A A B
FA
+ +
0 U5
- - RON = {RON} Acom Bcom 0
/FA S
AND REF
+ 0 /A /B
/FB
- +
- U1
UNI-POLAR_STEP_MOTR
FB FB.
VCC L = 2.5M
HY S_I-CTRL R = 4.2
U10 VHY S = {VHY S} D2
2-PHASE U8 I_SET = {I_SET} DIODE
PPS = 100 /FA S2 /A
+ +
- -
U4 RON = {RON}
S
Two-Phase AND
+
REF
0
Step Sequence - +
Generator (100
-
FB.
VCC
pps) HY S_I-CTRL
VHY S = {VHY S} D3
U7 I_SET = {I_SET} DIODE
/FB S3 /B
+ +
- -
U3 RON = {RON}
S
AND REF
+ 0
- +
-
FB.
VCC
HY S_I-CTRL
VHY S = {VHY S} D4
U6 I_SET = {I_SET} DIODE
FB S4 B
+ +
U2
- - RON = {RON}
S
AND REF
+ 0
- +
-
FB.
HY S_I-CTRL
VHY S = {VHY S} *Analysis directives:
PARAMETERS: I_SET = {I_SET} PARAMETERS:
I_SET = 0.5
VHY S = 0.1
RON = 10m .TRAN 0 40ms 0 10u SKIPBP
.OPTIONS ITL4= 40
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7.2 Two-Phase Sequence Drive, IPHASE=0.5A, IRIPPLE=0.1A
5.0V
Clock
2.5V
0V
V(CLK)
5.0V 1.0A
1 2 Phase A Current I_HYS=0.1A
2.5V 0.5A
>> I_SET=0.5A
0V 0A
1 V(FA) 2 -I(U1:A)
5.0V 1.0A
1 2 Phase /A Current
2.5V 0.5A
>>
0V 0A
1 V(/FA) 2 -I(U1:/A)
5.0V 1.0A
1 2
Phase B Current
2.5V 0.5A
>>
0V 0A
1 V(FB) 2 -I(U1:B)
5.0V 1.0A
1 2 Phase /B Current
2.5V 0.5A
SEL>>
0V 0A
0s 10ms 20ms 30ms 40ms
1 V(/FB) 2 -I(U1:/B)
Time
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7.3 Half-Phase Sequence Drive, IPHASE=0.5A, IRIPPLE=0.1A
VCC VCC VCC VCC
CLK
D1 Vcc
R1 U9 DIODE 12
CLK
1k FA S1 A A B
FA
+ +
0 U5
- - RON = {RON} Acom Bcom 0
/FA S
AND REF
+ 0 /A /B
/FB
- +
- U1
UNI-POLAR_STEP_MOTR
FB FB.
VCC L = 2.5M
HY S_I-CTRL R = 4.2
U10 VHY S = {VHY S} D2
HALF-STEP U8 I_SET = {I_SET} DIODE
PPS = 100 /FA S2 /A
+ +
- -
U4 RON = {RON}
S
Half-Phase AND
+
REF
0
Step Sequence - +
Generator (100
-
FB.
VCC
pps) HY S_I-CTRL
VHY S = {VHY S} D3
U7 I_SET = {I_SET} DIODE
/FB S3 /B
+ +
- -
U3 RON = {RON}
S
AND REF
+ 0
- +
-
FB.
VCC
HY S_I-CTRL
VHY S = {VHY S} D4
U6 I_SET = {I_SET} DIODE
FB S4 B
+ +
U2
- - RON = {RON}
S
AND REF
+ 0
- +
-
FB.
HY S_I-CTRL
VHY S = {VHY S} *Analysis directives:
PARAMETERS: I_SET = {I_SET} PARAMETERS:
I_SET = 0.5
VHY S = 0.1
RON = 10m .TRAN 0 80ms 0 10u SKIPBP
.OPTIONS ITL4= 40
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7.3 Half-Phase Sequence Drive, IPHASE=0.5A, IRIPPLE=0.1A
5.0V
Clock
2.5V
0V
V(CLK)
5.0V 1.0A
1 2 Phase A Current I_HYS=0.1A
2.5V 0.5A
>> I_SET=0.5A
0V 0A
1 V(FA) 2 -I(U1:A)
5.0V 1.0A
1 2 Phase /A Current
2.5V 0.5A
>>
0V 0A
1 V(/FA) 2 -I(U1:/A)
5.0V 1.0A
1 2
Phase B Current
2.5V 0.5A
>>
0V 0A
1 V(FB) 2 -I(U1:B)
5.0V 1.0A
1 2 Phase /B Current
2.5V 0.5A
SEL>>
0V 0A
0s 10ms 20ms 30ms 40ms 50ms 60ms 70ms 80ms
1 V(/FB) 2 -I(U1:/B)
Time
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8.Drive Circuit Efficiency (%)
VCC VCC VCC VCC
CLK
D1 Vcc
R1 U9 DIODE 12
CLK
1k FA S1 A A B
FA W
+ +
0 U5
- - RON = {RON} Acom Bcom 0
/FA S
AND REF
+ 0 /A
W
/B
/FB
- +
- U1
UNI-POLAR_STEP_MOTR
FB FB.
VCC L = 2.5M
HY S_I-CTRL R = 4.2
U10 VHY S = {VHY S} D2
1-PHASE U8 I_SET = {I_SET} DIODE
PPS = 100 /FA S2 /A
+ +
- -
U4 RON = {RON}
S
Half-Phase AND
+
REF
0
Step Sequence - +
Generator (100
-
FB.
VCC
pps) HY S_I-CTRL
VHY S = {VHY S} D3
U7 I_SET = {I_SET} DIODE
/FB S3 /B
+ +
- -
U3 RON = {RON}
S
AND REF
+ 0
- +
-
FB.
VCC
HY S_I-CTRL
VHY S = {VHY S} D4
U6 I_SET = {I_SET} DIODE
FB S4 B
+ +
U2
- - RON = {RON}
S
AND REF
+ 0
- +
-
FB.
HY S_I-CTRL
VHY S = {VHY S} *Analysis directives:
PARAMETERS: I_SET = {I_SET} PARAMETERS:
I_SET = 0.5 RON = 10m .TRAN 0 40ms 0ms 10u SKIPBP
VHY S = 0.1
.STEP PARAM RON LIST 10m, 100m, 1
.OPTIONS ITL4= 40
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8.Drive Circuit Efficiency (%)
100
at switches Ron = 10m, (99.6%)
at switches Ron = 100m, (99.3%)
98
96 at switches Ron = 1, (95.9%)
94
10ms 15ms 20ms 25ms 30ms 35ms 40ms
100* AVG(W(U1))/(-AVG(W(Vcc)))
Time
Note: Add trace 100*AVG(W(U1))/(-AVG(W(Vcc))) for the Efficiency.
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Simulation Index
Simulations Folder name
1. One-Phase Sequence Drive, IPHASE=0.5A, IRIPPLE=0.1A................................... 1-Phase
2. Two-Phase Sequence Drive, IPHASE=0.5A, IRIPPLE=0.1A................................... 2-Phase
3. Half-Phase Sequence Drive, IPHASE=0.5A, IRIPPLE=0.1A.................................... Half-Phase
4. Drive Circuit Efficiency (%)............................................................................... Efficiency
Libraries :
1. ..¥unipolar_stp-motr.lib
2. ..¥diode.lib
3. ..¥hys_i-ctrl.lib
4. ..¥logicgate.lib
5. ..¥step-seq.lib
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