Typical Performance Characteristics
Source Saturation Voltage vs. Output Current
(Recirculation Period)
Source Saturation Voltage vs. Output Current
(Conduction Period)
4
3
2
1
0
4
3
2
1
0
0.2
0.4
0.6
0.8
0.2
0.4
0.6
0.8
I (A)
I (A)
Sink Saturation Voltage vs. Output Current
Comparator Threshold vs. Junction Temperature
4
3
2
1
0
100
80
60
40
20
0
0.2
0.4
0.6
0.8
20 40 60 80 100 120 140 160
TJ (C)
I (A)
Application Information
The application diagram shows a typical application in
which two CS3717A's control a two phase bipolar stepper
motor.
Control of the motor
The stepper motor can rotate in either direction according
to the sequence of the input signals. It is possible to obtain
a full step, a half step and quarter step operation.
Programming
The amplitude of the current flowing in the motor wind-
ing is controlled by the logic inputs IN0 and IN1. The
truth table (page 3) shows three current levels and an off
state. A high level on the ÒDirectionÓ logic input sets the
direction of that current from OUTA to OUTB; a low level
from OUTB to OUTA.
Full step operation
Both windings of the stepper motor are energized all the
time with the same current IMA = IMB
.
IN0 and IN1 remain fixed at whatever torque value is
required.
Calling A the condition with winding A energized in one
direction and A in the other direction, the sequence for
full step rotation is:
It is recommended that unused inputs are tied to VCC or
(Gnd) as appropriate to avoid noise problems.
The current levels can be varied continuously by changing
AB®AB®AB®AB etc.
VREF
.
4
CHERRY [ CHERRY SEMICONDUCTOR CORPORATION ]
