MITSUBISHI <CONTROL / DRIVER IC>
M54676P
2-PHASE STEPPER MOTOR DRIVER
DESCRIPTION
The M54676P is a semiconductor IC to drive a bipolar stepper
PIN CONFIGURATION (TOP VIEW)
motor by the micro step method by changing the coil current of the
motor continuously.
20 VM
2
19 OutB
3
18 Out ∗B
4
17 SG B
GND
5
GND
6
Vref A
7
14 Sense B
Phase A
8
13 VrefB
Phase ∗A
9
12 PhaseB
●Bipolar and constant current drive
●Built in a thermal shutdown circuit and standby circuits
APPLICATION
M54676P
SG A
transistor and source output transistor simultaneously
●Built in flywheel diodes
1
Sense A
FEATURES
●Highly-accurate micro step drive by chopping sink output
OutA
Out ∗A
Vcc5 10
16 GND
15 GND
11 Phase ∗B
Office automation equipment such as printer and FAX
Outline 20P4
FUNCTION
The M54676P can drive a stepper motor by the 2-phase bipolar
method and also controls the coil current.
Furthermore, it controls the direction of the coil current by Ph input
and the coil current value by Vref pin.
Because two control circuits are built in this IC, a stepper motor
can be driven with a single IC by the 2-phase bipolar method.
BLOCK DIAGRAM
OUT A
Vref A Amp
OUT ∗A
VrefA
7
VM
VrefB
13
20
1
2
Vref 2 comparator
+
+
-
-
9KΩ
0.2V
+
-
1KΩ Current
comparator
Vref 2
comparator
Vref B Amp
3
SGA
+
+
-
18 OUT ∗B
0.2V
+
Vcc5 10
1KΩ
20KΩ
6KΩ
19 OUT B
-
9KΩ
Internal
bias
-
Current
comparator
TSD
11 12
16 15 6
GND
5
17
SGB
Phase ∗B
PhaseB
9
Phase ∗A
SenseB
SenseA
8
PhaseA
4 14
MITSUBISHI <CONTROL / DRIVER IC>
M54676P
2-PHASE STEPPER MOTOR DRIVER
ABSOLUTE MAXIMUM RATINGS (Ta= 25˚C, unless otherwise noted)
Symbol
VM
Vcc5
Iout
Vanalg
Vlogic
Parameter
Supply voltage 1
Supply voltage 2
Maximum output current
Analog input voltage
Logic input voltage
Pt
Allowable loss
Kθ
Thermal derating
Junction temperature
Operating temperature
Storage temperature
Tj
Ta
Tstg
Conditions
Pin
Pin
20
10
Pins 4 7 13 and 14
Pins 8 9 11 and 12
100mm x 100mm, t=1.6mm
Glass epoxy board (θ ja=50˚C/W )
ditto
Ratings
Vcc5 – 20
-0.3 – 7
±500
-0.3 – 7
-0.3 – 7
Unit
V
V
mA
V
V
2.5
W
20.0
150
0 – 75
-20 – 125
mW/˚C
˚C
˚C
˚C
ELECTRICAL CHARACTERISTICS (DC CHARACTERISTICS) (Ta=25˚C, VM=12V, Vcc=5V, unless otherwise noted)
Symbol
Vsat
Vcc5 H
Vcc5 L
Icc10
Icc20
Istby
Ivref
Test conditions
Parameter
Min.
Output saturation voltage
Vcc5 input voltage H
Vcc5 input voltage L
Circuit current
VM reactive current
Standby VM current
Vref input bias current
Load=350mA (total)
Pin 10 (Vcc5) voltage (Operating mode)
Pin 10 (Vcc5) voltage (Standby mode)
Pin 10 current (Vcc5=5V)
Pin 20 current (VM=12V, Vcc5=5V)
Pin 20 current (VM=12V, Vcc5=0V)
Vref=0V
Vref
Vref amplifier input voltage range
See Vref-Vsense characteristics 12-4
Vcoff : Comparator OFF reference voltage
Vcc off
Vsense
Sense pin threshold voltage
Sense pin voltage when output changes at
Vref=2.5V
230
Vcoff
Comparator OFF reference voltage
0.1
Vin H
Vin L
Iin H
Iin L
Isense
Ioff
Logic input voltage H
Logic input voltage L
Logic input current H
Logic input current L
Sense input current
Output cutoff current
Pins
Pins
Pins
Pins
Pins
Pins
8
9
8
9
8
9
8
9
4
14
1
2
and
and
11 and
11 and
=0V
11 and
11
12
11
12
12
12
4.5
0
-200
Limits
Typ.
1.35
5.0
38
6
0
-10
-20
-15
12
Unit
V
V
V
mA
mA
µA
nA
Vcc5
-1.5
V
250
270
mV
0.2
0.3
V
Vcc5
0.8
10
V
V
µA
µA
µA
µA
2.0
0
=5V
=0V
Max.
1.8
5.5
0.8
57
20
100
0
-7
-2
0
100
ELECTRICAL CHARACTERISTICS (AC CHARACTERISTICS) (Ta=25˚C, VM=12V, Vcc=5V, unless otherwise noted)
Symbol
Parameter
Test conditions
Min.
Limits
Typ.
Max.
Unit
Tdon
Output turn-on delay
Time required to turn on output when Sense pin
voltage is decreased from 0.5V to 0V at Vref=2.5V
0.3
1.0
µS
Tdoff
Output turn-off delay
Time required to turn off output when Sense pin
voltage is increased from 0V to 0.5V at Vref=2.5V
1.5
2.5
µS
Tdamp
Vref amplifier response time
Time required to turn on output when Vref pin voltage
is increased from 0V to 3.5V at Sense=0.25V
10
30
µS
Tdph
Phase delay time
Time required to turn on output when Phase pin voltage is
increased from 0V to 5V at Vref=2.5V and Sense=0V
3
12
µS
Tdoff
Tdon
MITSUBISHI <CONTROL / DRIVER IC>
M54676P
2-PHASE STEPPER MOTOR DRIVER
• Standby circuit
FUNCTION DESCRIPTION
• Phase input
When Vcc5 voltage is 0.8V or below or open, the IC goes in the
Phase input decides the output mode.
standby state. In the standby state, leak current does not flow into
VM power supply, logic input pins (Phase input), and analog input
PhaseA
(PhaseB)
Phase ∗A
(Phase ∗B)
OutA
(OutB)
Out ∗A
(Out ∗B)
pins (Vref input and Sense input). Never forget to set VM power
H
L
H
L
applied to the IC in the standby state. (As for details, refer to
L
H
L
H
“PRECAUTIONS FOR USE.”)
H
H
Z
Z
L
L
Z
Z
*Z: High impedance
In order to prevent through current caused by turning on output
transistors simultaneously at PhaseA=Phase ∗A=“H”, both phase
inputs go in the high mode simultaneously and output goes in the
high impedance state.
Furthermore, as a countermeasure against output through current
supply to be the maximum voltage level among all voltages
• Thermal shutdown (TSD) circuit
This IC has the thermal shutdown function to protect itself against
damage by a fire when chip temperature rises abnormally.
• Flywheel diode
Because flywheel diodes for chopper current control are built in
this IC, it is not necessary to connect external flywheel diodes.
at the time of phase switching, a delay time (3us) to turn on the
Also, by connecting schottky diodes with low VF externally, it is
motor drive output when phase input goes in high state is set
possible to reduce thermal loss.
within the IC.
• Vref input (Comparative voltage)
Chopper current (motor current) is controlled by changing Vref
input voltage.
By inputting SIN wave to VrefA and COS wave to VrefB, A-phase
coil current and B-phase coil current change continuously and the
microstep drive of a stepper motor is performed.
• Current comparator
Sense pin voltage (voltage fall at current sensing resistor = motor
current) and Vref input proportional voltage (Vref/10) are
compared.
Sense pin voltage < Vref/10: the comparator output is in high
state and output transistors are turned on. Then, current flows into
the motor.
Sense pin voltage > Vref/10: the comparator output is in low state
and output transistors are turned off. Current does not flow into
the motor.
The above operation is repeated to control the current of the
motor.
• Vref comparator
Vref input proportional voltage {(Vref/10)} and internal reference
voltage are compared. If Vref input voltage is 0.3V or lower,
output transistors are turned off and motor current stops
regardless of Phase input and Sense input.
MITSUBISHI <CONTROL / DRIVER IC>
M54676P
2-PHASE STEPPER MOTOR DRIVER
APPLICATION EXAMPLE
φA
Stepper motor
φB
12V
1
OutA
VM
20
2
Out ∗A
OutB
19
3
SGA
Out ∗B
18
4
SenseA
SGB
17
5
GND
GND
16
RS1
SR1
RS2
SC1
SR2
6
GND
GND
15
SC2
D/A input
5V
7
VrefA
8
PhaseA
9
Phase ∗A
10
VCC5
SenseB
14
VrefB
13
PhaseB
12
Phase ∗B
11
RS1,RS2 = 0.5Ω
SR1,SR2 = 1.6KΩ
SC1,SC2 = 0.1µF
D/A input
MITSUBISHI <CONTROL / DRIVER IC>
M54676P
2-PHASE STEPPER MOTOR DRIVER
PRECAUTIONS FOR USE
Wiring on the board
Sequence of supply voltage (VM and Vcc5) and logic
input voltage
Current is controlled by flowing output current to the current
sensing resistor (1 ohmlevel) to measure the voltage fall.
The output current performs the chopping operation at high speed.
Therefore, wiring to flow current and to connect the highimpedance input pin (Vref) should be conducted carefully not to
cause a cross talk.
The VM voltage should be the maximum voltage among all voltages applied to this IC. If no voltage is applied to VM and 5V
voltage is applied to Vcc5 pin and logic input pin, leak current flows
from Vcc5 pin and logic input pin to VM through a surge protection
diode.
VM
Vcc5
Logic
input
12V
5V
5V,0V
Normal operation mode
12V
0V
(Open)
5V,0V
Standby mode (No current flows to
logic input pin and Vcc pin.)
5V,0V
Leak current flows
from Vcc5 pin and
Prohibited
logic input pin to
VM pin.
0V
(Open)
5V
Mode
Sequence
After the VM voltage rises, set the Vcc5 power supply voltage and
logic input voltage. Similarly, after Vcc5 supply voltage and logic
input voltage rise, raise the VM supply voltage.
Time
VM
Vcc5
and
logic input
Thermal shutdown function
The circuit board on which this IC is mounted is designed to realize
low impedance between power supply and output pin. Therefore, it
is desirable to take a safe measure such as fixing a fuse to avoid
such a situation that the board is damaged by a fire when output
pin is internally short-circuited by excessive surge voltage applied
externally by accident (or when the TSD function is damaged).
Thermal loss
In case that conditions for use (regarding supply voltage and
output current) or a board used is changed, sufficient thermal
evaluation should be conducted and design should be worked out
to leave a margin for thermal loss. The higher the chopping
frequency is, the larger switching loss within the IC becomes.