鈥?/div>
Full-Step, Half-Step and Micro-Step
Capability
Bipolar Output Current up to 1A
Wide Range of Motor Supply Voltage
10-46V
Low Saturation Voltage with Integrated
Bootstrap
Built-In Fast Recovery Commutating
Diodes
Current Levels Selected in Steps or Varied
Continuously
Thermal Protection with Soft Intervention
DESCRIPTION
The UC3717A is an improved version of the UC3717, used to switch
drive the current in one winding of a bipolar stepper motor. The
UC3717A has been modified to supply higher winding current, more
reliable thermal protection, and improved efficiency by providing inte-
grated bootstrap circuitry to lower recirculation saturation voltages.
The diagram shown below presents the building blocks of the
UC3717A. Included are an LS-TTL compatible logic input, a current
sensor, a monostable, a thermal shutdown network, and an H-bridge
output stage. The output stage features built-in fast recovery com-
mutating diodes and integrated bootstrap pull up. Two UC3717As
and a few external components form a complete control and drive
unit for LS-TTL or micro-processor controlled stepper motor systems.
The UC3717A is characterized for operation over the temperature
range of 0擄C to +70擄C.
ABSOLUTE MAXIMUM RATINGS (Note 1)
Voltage
Logic Supply, V
CC
. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 7V
Output Supply, V
m
. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 50V
Input Voltage
Logic Inputs (Pins 7, 8, 9) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6V
Analog Input (Pin 10). . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . V
CC
Reference Input (Pin 11) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 15V
Input Current
Logic Inputs (Pins 7, 8, 9) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . -10mA
Analog Inputs (Pins 10, 11) . . . . . . . . . . . . . . . . . . . . . . . . . . . . -10mA
Output Current (Pins 1, 15) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
鹵
1.2A
Junction Temperature, T
J
. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . +150擄C
Storage Temperature Range, T
S
. . . . . . . . . . . . . . . . . . -55擄C to +150擄C
Note 1: All voltages are with respect to ground, Pins 4,
5, 12, 13. Currents are positive into, negative out of the
specified terminal. Pin numbers refer to DIL-16 pack-
age.
Consult Packaging Section of Databook for thermal limi-
tations and considerations of package.
BLOCK DIAGRAM
4/97
1
1
2
3
4
5
6
7
8
9
