NJM3772D2 [NJRC]
DUAL STEPPER MOTOR DRIVER; 双步进电机驱动器
| 型号： | NJM3772D2 |
| 厂家： | 
NEW JAPAN RADIO |
| 描述： | DUAL STEPPER MOTOR DRIVER |
| 文件： | 总9页 (文件大小：166K) |
| 中文： | 中文翻译 | 下载： | 下载PDF数据表文档文件 |
NJM3772
DUAL STEPPER MOTOR DRIVER
■ GENERAL DESCRIPTION
■ PACKAGE OUTLINE
The NJM3772 is a stepper motor driver, which circuit is
especially developed for use in microstepping applications in
conjunction with the matching dual DAC (Digital-to-Analog
Converter) NJU39610.
The NJM3772 contains a clock oscillator, which is common
for both driver channels, a set of comparators and flip-flops
implementing the switching control, and two H-bridges with
internal recirculation diodes. Voltage supply requirements are
+5 V for logic and +10 to +45V for the motor. Maximum output
current is 1000mA per channel.
NJM3772FM2
NJM3772D2
■ FEATURES
• Dual chopper driver
• 1000mA continuous output current per channel
• Specially matched to the Dual DAC NJU39610
• Packages DIP22 / PLCC28
■ BLOCK DIAGRAM
E
Phase
V
C
1
V
1
MM1
1
R1
NJM3772
—
V
V
CC
CC
Q
R
S
+
M
M
A1
B1
Logic
V
V
BB1
BB2
+
—
M
M
B2
A2
Logic
RC
S
R
Q
+
—
E
V
Phase
V
C
GND
2
MM2
2
2
R2
Figure 1. Block diagram
NJM3772
■ PIN CONFIGURATIONS
RC
1
2
22
21
20
V
CC
C
2
C
1
V
3
V
R2
R1
V
5
6
25
24
V
C
R2
BB2
Phase
4
19 Phase
18 GND
17 GND
2
1
E
2
2
M
M
7
23 RC
B2
B1
GND
5
8
22
21
20
V
CC
NJM
3772D2
NJM3772FM2
GND
6
GND
9
C
V
1
E
1
10
11
R1
7
16
15
14
13
12
V
MM1
V
MM2
V
19 Phase
BB1
1
M
A2
8
M
A1
9
V
BB2
V
E
BB1
E
2
10
11
1
M
M
B2
B1
Figure 2. Pin configurations
■ PIN DESCRIPTION
PLCC
DIP
Symbol
Description
1-3, 9, 5, 6
13-17 17, 18
28
GND
Ground and negative supply. Note: these pins are used thermally for heat-sinking.
Make sure that all ground pins are soldered onto a suitably large copper ground
plane for efficient heat sinking.
4
5
8
9
MA2
VBB2
Motor output A, channel 2. Motor current flows from MA2 to MB2 when Phase2 is HIGH.
Collector of upper output transistor, channel 2. For lowest possible power dissipation, connect a
series resistor RB2 to VMM2. See Applications information, External components.
Common emitter, channel 2. This pin connects to a sensing resistor RS to ground.
Motor output B, channel 2. Motor current flows from MA2 to MB2 when Phase2 is HIGH.
Motor output B, channel 1. Motor current flows from MA1 to MB1 when Phase1 is HIGH.
Common emitter, channel 1. This pin connects to a sensing resistor RS to ground.
Collector of upper output transistor, channel 1. For lowest possible power dissipation, connect a
series resistor RB1 to VMM1. See Applications information, External components.
Motor output A, channel 1. Motor current flows from MA1 to MB1 when Phase1 is HIGH.
Motor supply voltage, channel 1, +10 to +40 V. VMM1 and VMM2 should be connected together.
Controls the direction of motor current at outputs MA1 and MB1. Motor current flows from MA1 to MB1
when Phase1 is HIGH.
6
7
8
10
11
10
11
12
13
14
E2
MB2
MB1
E1
VBB1
12
18
19
15
16
19
MA1
VMM1
Phase1
20
21
20
21
VR1
C1
Reference voltage, channel 1. Controls the threshold voltage for the comparator and hence the
output current.
Comparator input channel 1. This input senses the instantaneous voltage across the sensing
resistor, filtered by an RC network. The threshold voltage for the comparator is VCH1= 0.18 • VR1 [V],
i.e. 450 mV at VR1 = 2.5 V.
22
23
22
1
VCC
RC
Logic voltage supply, nominally +5 V.
Clock oscillator RC pin. Connect a 15 kohm resistor to VCC and a 3300 pF capacitor to ground to
obtain the nominal switching frequency of 26.5 kHz.
24
2
C2
Comparator input channel 2. This input senses the instantaneous voltage across the sensing
resistor, filtered by an RC network. The threshold voltage for the comparator is VCH2= 0.18 • VR2 [V],
i.e. 450 mV at VR2 = 2.5 V.
25
26
27
3
4
7
VR2
Reference voltage, channel 2. Controls the threshold voltage for the comparator and hence the
output current.
Controls the direction of motor current at outputs MA2 and MB2. Motor current flows from MA2 to MB2
when Phase2 is HIGH.
Phase2
VMM2
Motor supply voltage, channel 2, +10 to +40 V.VMM1 and VMM2 should be connected together.
NJM3772
■ FUNCTIONAL DESCRIPTION
Each channel of the NJM3772 consists of the following sections: an output H-bridge with four transistors, capable
of driving up to 1000 mA continuous current to the motor winding; a logic section that controls the output transis-
tors; an S-R flip-flop; and a comparator. The clock-oscillator is common to both channels.
Constant current control is achieved by switching the output current to the windings. This is done by sensing the
peak current through the winding via a current-sensing resistor RS, effectively connected in series with the motor
winding during the turn-on period. As the current increases, a voltage develops across the sensing resistor, which
is fed back to the comparator. At the predetermined level, defined by the voltage at the reference input VR, the
comparator resets the flip-flop, which turns off the output transistors. The current decreases until the clock oscillator
triggers the flip-flop, which turns on the output transistors again, and the cycle is repeated.
The current paths during turn-on, turn-off and phase shift are shown in figure 3. Note that the upper recirculation
diodes are connected to the circuit externally.
External recirculation diodes
VMM
1
R
B
VBB
2
3
RS
Motor Current
1
2
3
Time
Fast Current Decay
Slow Current Decay
Figure 3. Output stage with current paths
during turn-on, turn-off and phase shift.
NJM3772
■ ABSOLUTE MAXIMUM RATINGS
Parameter
Pin no. DIP package
Symbol
Min
Max
Unit
Voltage
Logic supply
Motor supply
Output stage supply
Logic inputs
Comparator inputs
Reference inputs
22
VCC
VMM
VBB
VI
VC
VR
0
0
0
-0.3
-0.3
-0.3
7
45
45
6
VCC
7.5
V
V
V
V
V
V
7, 16
9, 14
4, 19
2, 21
3, 20
Current
Motor output current
Logic inputs
Analog inputs
8, 11, 12, 15
4, 19
2, 3, 20, 21
IM
II
IA
-1200
-10
-10
+1200
mA
mA
mA
-
-
Temperature
Operating junction temperature
Storage temperature
Tj
TS
-40
-55
+150
+150
°C
°C
Power Dissipation (Package Data)
Power dissipation at TGND = +25°C, DIP and PLCC package
Power dissipation at TGND = +125°C, DIP package
Power dissipation at TGND = +125°C, PLCC package
PD
PD
PD
-
-
-
5
2.2
2.6
W
W
W
■ RECOMMENDED OPERATING CONDITIONS
Parameter
Symbol
VCC
VMM
VBB
IM
TJ
tr, tf
RT
Min
4.75
10
VMM- 0.5
-1000
-20
Typ
Max
5.25
40
VMM
+1000
+125
2
Unit
V
V
Logic supply voltage
Motor supply voltage
Output stage supply voltage
Motor output current
Junction temperature **
Rise and fall time, logic inputs
Oscillator timing resistor
5
-
-
-
-
V
mA
°C
µs
kΩ
-
2
-
15
20
** See operating temperature chapter
E
Phase
19
V
C
V
1
1
R1
1
MM1
20
21
16
13
| V
– V
|
NJM3772
Pin no.
refers to DIP-package
MA
MB
t
—
+
V
V
I
CC
CC
CC
Q
R
S
22
M
15
A1
B1
t
on
off
M
Logic
12
50 %
V
V
14
9
BB1
BB2
15 kΩ
+
R
—
T
M
M
11
8
t
B2
A2
I
I
OL
M
Logic
V
t
I
RC
RC
d
E
1
S
R
Q
+
—
R
V
B
CH
3
300 pF
V
CC
C
T
5, 6, 17, 18
GND
7
10
E
4
3
2
Phase
V
C
V
2
2
MM2
2
R2
I
MM
I
I
I
I
IH
IL
A
I
I
C
I
A
V
I
1 kΩ
t
V
R
V
CH
V
V
V
V
V
MM
V
C
A
E
M
BB
IH
V
t
V
V
R
1
+ t
on
+
820 pF
MA
IL
C
f =
D =
s
t
t
R
t
C
C
on
off
S
on
off
Figure 4. Definition of symbols
Figure 5. Definition of terms
NJM3772
■ ELECTRICAL CHARACTERISTICS
Electrical characteristics over recommended operating conditions, unless otherwise noted. -20°C< TJ < 125°C
Parameter
Symbol
Conditions
Min
Typ
Max
Unit
General
Supply current
Total power dissipation
ICC
PD
Note 4.
-
-
60
1.8
75
2.1
mA
W
VMM = 12 V, IM1= IM2= 750 mA.
RB = 0.68 ohm. Notes 2, 3, 4, 5.
VMM = 12 V, IM1 = 1000 mA, IM2 = 0 mA.
RB = 0.47 ohm. Notes 2, 3, 4, 5.
Total power dissipation
PD
-
1.8
2.2
W
Thermal shutdown junction temperature
Turn-off delay
-
-
160
1.4
-
°C
µs
td
TA = +25°C, dVC/dt ≥ 50 mV/µs,
2.0
IM = 100 mA. Note 3.
Logic Inputs
Logic HIGH input voltage
Logic LOW input voltage
Logic HIGH input current
Logic LOW input current
VIH
VIL
IIH
2.0
-
-
-
-
-
-
-
0.8
20
-
V
V
µA
mA
VI = 2.4 V
VI = 0.4 V
IIL
-0.4
Comparator Inputs
Threshold voltage
| VCH1 - VCH2 | mismatch
Input current
VCH
RC = 1 kohm, VR = 2.50 V
430
-
-10
450
1
-
470
-
1
mV
mV
µA
VCH,diff RC = 1 kohm
IC
Reference Inputs
Input resistance
Input current
RR
IR
TA = +25°C
VR = 2.50 V
-
-
5
0.5
-
kohm
mA
1.0
Motor Outputs
Lower transistor saturation voltage
Lower transistor leakage current
Lower diode forward voltage drop
Upper transistor saturation voltage
Upper transistor saturation voltage
Upper transistor leakage current
IM = 750 mA
-
-
-
-
-
-
0.6
-
1.2
0.6
0.8
-
0.9
700
1.5
0.9
1.1
700
V
µA
V
V
V
VMM = 41 V, VE = VR = 0 V, VC = VCC
IM = 750 mA
IM = 750 mA. RB = 0.68 ohm. Note 5
IM = 750 mA. RB = 0.47 ohm. Note 3, 5
VMM VBB = 41 V, VE = VR = 0 V, VC = VCC
µA
Chopper Oscillator
Chopping frequency
fs
CT = 3300 pF, RT = 15 kohm
25.0
26.5
28.0
kHz
■ THERMAL CHARACTERISTICS
Parameter
Symbol
Conditions
Min
Typ
11
40
9
Max
Unit
Thermal resistance
RthJ-GND DIP package
-
-
-
-
-
-
-
-
°C/W
°C/W
°C/W
°C/W
RthJ-A
DIP package. Note 2
RthJ-GND PLCC package
RthJ-A
PLCC package. Note 2
35
Notes
1. All voltages are with respect to ground. Currents are positive into, negative out of specified terminal
2. All ground pins soldered onto a 20 cm2 PCB copper area with free air convection, TA = +25°C
3. Not covered by final test program
4. Switching duty cycle D = 30%, fs = 26.5 kHz
5. External resistors RB for lowering of saturation voltage
NJM3772
■ APPLICATIONS INFORMATION
Current control
The output current to the motor winding is determined by the voltage at the reference input and the sensing
resistor, RS.
Chopping frequency, winding inductance and supply voltage also affect the current, but to much less extent.
The peak current through the sensing resistor (and motor winding) can be expressed as:
IM,peak = 0.18 • ( VR / RS )[A]
i.e., with a recommended value of
0.47 ohm for the sensing resistor RS, a 2.5 V reference voltage will produce an output current of approximately
960 mA.
To improve noise immunity on the VR input, the control range may be increased to 5 V if RS is correspondingly
changed to 1 ohm.
V
+5 V
MM
+
R
R
B
B
10 µF
0.1µ F
0.5 Ω
11
0.5 Ω
D1
D2
22
18
27
5
12
V
V
V
V
V
M
MM2
MM1
BB1
CC
BB2
A1
19
Phase
1
2
8
4
20
M
B1
V
R1
NJM3772
M
26
25
A2
Phase
7
V
M
R2
B2
RC
E
C
2
C
GND
E
2
1
1
STEPPER
MOTOR
23
6
10
1 kΩ
24
1, 2,
3, 9,
28, 13,
14, 15,
16, 17,
21
1 kΩ
15 kΩ
+5 V
D3
D4
V
MM
3300 pF
820 pF
820 pF
R
D1 - D4 are UF 4001 or
R
S
S
BYV 27, t ≤ 100 ns.
rr
0.5 Ω
0.5 Ω
Pin numbers
GND (V
)
MM
GND (V
CC
)
refer to PLCC
package.
Figure 6. Typical stepper motor driver application with NJM3772
V
(+5V)
V
CC
MM
+
R
R
B
B
0.1 µF
10 µF
0.5 Ω
0.5 Ω
11
D1
D2
22
18
27
5
14
25
V
V
V
V
V
12
V
D0
DD
CC
MM1
BB1
MM2
M
M
M
BB2
A1
B1
A2
B2
12
10
19
Sign
Phase
1
1
2
20
8
4
16
D7
DA
V
1
R1
To
mP
NJU39610
NJM3772
27
A0
26
25
4
6
28
A1
Phase
Sign
2
15
WR
1
CS
7
V
DA
7
R2
2
M
6
RESET
9
+2.5V
V
V
GND
C
E
C
E
Ref
SS
RC
23
STEPPER
MOTOR
2
1
1
2
10
1 kΩ
24
1, 2,
3, 9,
28, 13,
14, 15,
16, 17,
21
2
1 kΩ
15 kΩ
+5 V
D3
D4
V
MM
3300 pF
820 pF
R
820 pF
R
D1 - D4 are UF 4001 or
100 ns
S
S
BYV 27, t
rr
0.5 Ω
0.5 Ω
Pin numbers refer to
PLCC package.
Figure 7. Microstepping system with NJU39610 and NJM3772
NJM3772
External components
The NJM3772 exhibits substantially less power dissipation than most other comparable stepper motor driver ICs on
the market. This has been achieved by creating an external voltage drop in series with the upper transistor in the
output H-bridge, see figure 3. The voltage drop reduces the collector-emitter saturation voltage of the internal
transistor, which can greatly reduce power dissipation of the IC itself. The series resistor, designated RB , shall be
selected for about 0.5 V voltage drop at the maximum output current. In an application with an output current of
1000 mA (peak), a 0.47 ohm,
1/2 W resistor is the best choice.
In low current applications where power dissipation is not a critical factor, the RB resistor can of course be
omitted, and the VMM and VBB pins (pins 5, 11, 18, 27) can all be connected directly to the motor supply voltage VMM.
Contributing to the low power dissipation is the fact that the upper recirculation diodes in the output H- bridge are
connected externally to the circuit. These diodes shall be of fast type, with a trr of less than 100 ns. Common types
are UF4001 or BYV27.
A low pass filter in series with the comparator input prevents erroneous switching due to switching transients.
The recommended filter component values, 1 kohm and 820 pF, are suitable for a wide range of motors and
operational conditions.
Since the low-pass filtering action introduces a small delay of the signal to the comparator, peak voltage across
the sensing resistor, and hence the peak motor current, will reach a slightly higher level than than what is defined
by the comparator threshold, VCH , set by the reference input VR (VCH = 450 mV at VR= 2.5 V).
The time constant of the low-pass filter may therefore be reduced to minimize the delay and optimize low-current
performance. Increasing the time constant may result in unstable switching. The time constant should be adjusted
by changing the CC value.
The frequency of the clock oscillator is set by the RT-CT timing components at the RC pin. The recommended
values result in a clock frequency (= switching frequency) of 26.5 kHz. A lower frequency will result in higher
current ripple, but may improve low-current level linearity. A higher clock frequency reduces current ripple, but
increases the switching losses in the IC and possibly the iron losses in the motor. If the clock frequency needs to
be changed, the CT capacitor value should be adjusted. The recommended RT resistor value is 15 kohm.
The sensing resistor RS, should be selected for maximum motor current. The relationship between peak motor
current, reference voltage and the value of RS is described under Current control above. Be sure not to exceed the
maximum output current which is 1200 mA peak when only one channel is activated. Or recommended output
current, which is 1000 mA peak, when both channels is activated.
NJM3772
Motor selection
The NJM3772 is designed for two-phase bipolar stepper motors, i.e., motors that have only one winding per
phase.
The chopping principle of the NJM3772 is based on a constant frequency and a varying duty cycle. This scheme
imposes certain restrictions on motor selection. Unstable chopping can occur if the chopping duty cycle exceeds
approximately 50%. See figure 5 for definitions. To avoid this, it is necessary to choose a motor with a low winding
resistance and inductance, i.e. windings with a few turns.
It is not possible to use a motor that is rated for the same voltage as the actual supply voltage. Only rated current
needs to be considered. Typical motors to be used together with the NJM3772 have a voltage rating of 1 to 6 V,
while the supply voltage usually ranges from 12 to 40 V.
Low inductance, especially in combination with a high supply voltage, enables high stepping rates. However, to
give the same torque capability at low speed, a reduced number of turns in the winding must be compensated by a
higher current. A compromise has to be made.
Choose a motor with the lowest possible winding resistance that still gives the required torque, and use as high
supply voltage as possible, without exceeding the maximum recommended 40 V. Check that the chopping duty
cycle does not exceed 50% at maximum current.
Phase inputs.
A logic HIGH on a Phase input gives a current flowing from pin MA into pin MB. A logic LOW gives a current flow in
the opposite direction. A time delay prevents cross conduction in the H-bridge when changing the Phase input.
Heat sinking.
Soldering the batwing ground leads onto a copper ground plane of 20 cm2 (approx. 1.8" x 1.8"), copper foil thick-
ness 35 µm, permits the circuit to operate with 750 mA output current, both channels driving, at ambient tempera-
tures up to 70°C. Consult figures 8, 9, 10 and 11 in order to determine the necessary copper ground plane area for
heat sinking at higher current levels.
Thermal shutdown.
The circuit is equipped with a thermal shutdown function that turns the output off at chip temperatures above
160°C. Normal operation is resumed when the temperature has decreased.
Operating temperature.
The max recommended operating temperature is 125°C. This gives an estimated lifelength of about 5 years at
continuous drive, A change of ±10° would increase/decrease the lifelength of the circuit about 5 years.
Thermal resistance [°C/W]
80
28-pin PLCC
70
60
50
40
30
22-pin
DIP
20
5
10
15
20
25
30
35
PCB copper foil area [cm2]
PLCC package
DIP package
Figure 8. Typical thermal resistance vs. PC Board copper area and suggested layout
NJM3772
■ TYPICAL CHARACTERISTICS
Maximum allowable power dissipation [W]
PD (W)
PD (W)
NJM3772
NJM3772
6
5
4
3
2
1
0
3.0
3.0
2.5
2.0
1.5
1.0
.5
Two channels on.
= 0.68 ohm.
R
2.5
2.0
1.5
1.0
.5
Batwing
Ambient
V
= 36 V
MM
temperature
pin
temperature
Two channels on.
V
= 12 V
MM
R
= 0.47 ohm.
B
One channel on.
R
= 0.47 ohm.
B
-25
0
25
50
75
125
150
R
= 0.68 Ω
100
B
V
= 12 V
MM
Temperature [°C]
0
0
0
.20
.40
.60
IM (A)
.80
1.0
1.2
0
.20
.40
.60
.80
1.0
1.2
PLCC package
DIP package
All ground pins soldered onto a
20 cm2 PCB copper area with
free air convection.
IM (A)
Figure 10. Power dissipation vs. motor
Figure 9. Power dissipation vs.
Figure 11. Maximum allowable
current, both channels on. Ta = 25°C
motor current. Ta = 25°C
power dissipation vs. temperature
VCE Sat, ut (V)
VCE Sat, lt (V)
Vd (V)
NJM3772
PBL 3772
NJM3772
1.2
1.2
1.0
.8
1.0
1.2
1.0
.8
RB = 0.47Ω
.8
.6
.6
RB = 0.68Ω
TJ =25¡C
TJ =125¡C
.4
.4
.2
.6
.2
.4
0
.20
.40
.60
IM (A)
.80
1.0
1.2
.2
0
.20
.40
.60
IM (A)
.80
1.0
1.2
0
.20
.40
.60
IM (A)
.80
1.0
1.2
Figure 13. Typical lower diode voltage Figure 14. Typical upper transistor
Figure 12. Typical lower transistor
saturation voltage vs. output current
drop vs. recirculating current
saturation voltage vs. output current
The specifications on this databook are only
given for information , without any guarantee
as regards either mistakes or omissions.
The application circuits in this databook are
described only to show representative
usages of the product and not intended for
the guarantee or permission of any right
including the industrial rights.
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