M54640P Datasheet, PDF (1/6 Pages) Mitsubishi Electric Semiconductor – STEPPER MOTOR DRIVER

MITSUBISHI <CONTROL / DRIVER IC>
M54640P
STEPPER MOTOR DRIVER
DESCRIPTION
The M54640P is a semiconductor IC to drive a stepper motor by
the bipolar method.
FEATURES
q Bipolar and constant-current drive
q Wide current control rage (20 – 800mA)
q Wide supply voltage drive range (10 – 40V)
q Built in flywheel diodes
q Current level can be changed by steps or continuously.
q Built in a thermal shutdown circuit
APPLICATION
Printer, FDD, HDD, Fax
PIN CONFIGURATION (TOP VIEW)
Output MB ← 1
One-shot-multi
time constant
T→ 2
Output power
supply
VMM
3
4
GND
5
Power supply VCC ₆
Output current
value setting
Output current
direction switching
I1 7
Ph → 8
16 → E Current sensor
15 → ^MA ^Output
14
VMM
Output power
supply
13
GND
12
11 ← ^VR
Comparator
reference input
10 ← ^{C Comparator input}
9
Io
Output current
setting
Outline 16P4
FUNCTION
The M54640P drives a stepper motor by the bipolar drive method to
change the current direction of a single coil and controls the current
direction with PHASE input pin. In order to obtain higher efficiency,
the constant current drive system to control the coil current is
introduced. The current value can be selected among four levels (0
to max.) by selecting the combination of three internal comparators
by logic input. It also can be continuously changed by controlling
the reference voltage. Conversion to voltage is conducted by the
current value sensing resistor (Rs) and the voltage is sensed with
each comparator, and then each comparator output triggers
monomulti and the current is cut for a certain time (tOFF) by utilizing
the inductance of the coil.
Also, diodes needed for choppering and a thermal shutdown circuit
as a countermeasure against overvoltage are built in this circuit.
BLOCK DIAGRAM
Comparator reference input
VR
VCC
11
6
Cutput current
direction switcing
Ph
8
Output current
value setting
I1 7
I0 9
Schmitt trigger
Output
MA
15
Output
MB
1
1
1
3 VMM
14 _{Output power}
1
supply
>1
>1
00 01 10 11
VKH
VKM
Monostable
tOFF = 0.69 • RT CT
VKL
4
5
GND
12
13
Current sensor
10
C
Comparator input
2
T
One-shot-multi time constant
16
E
Current sensor