Texas Instruments UC3717AQTR, UC3717AQ, UC3717AN Datasheet

4/97

• 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

Stepper Motor Drive Circuit

The UC3717A is an impro ved ver sion of the UC3717, us ed 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 inte­grated boots trap circuitry to lower recirculation saturation voltages.
The diagram shown below presents the building blocks of the
UC3717A. Includ ed are an LS-TTL compatible l ogic input, a current
sensor, a monostable, a ther mal s hutd ow n netw ork, and an H -bridge
output stage. The output stage features built-in fast recovery com­mutating 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°C to +70°C.

UC3717A

BLOCK DIAGRAM

FEATURES DESCRIPTION

Voltage

Logic Supply, VCC. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 7V

Output Supply, Vm. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 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) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . ±1.2A

Junction Temperature, TJ. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . +150°C

Storage Temperature Range, TS. . . . . . . . . . . . . . . . . . -55°C to +150°C

ABSOLUTE MAXIMUM RATINGS (Note 1)

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 pack­age.
Consult Packaging Section of Databook for thermal limi­tations and considerations of package.

1

UC3717A

PLCC-20 (TOP VIEW)
Q Package

PACKAGE PIN FUNCTION

FUNCTION PIN

N/C

1

B

OUT

2

Timing

3

V

m

4

Gnd

5

N/C

6

Gnd

7

V

CC

8

I

1

9

Phase

10

N/C

11

I

0

12

Current

13

V

R

14

Gnd

15

N/C

16

Gnd

17

V

m

18

A

OUT

19

Emitters

20

DIL-16 (TOP VIEW)
J or N Package

CONNECTION DIAGRAMS

ELECTRICAL CHARACTERISTICS

(Refer to the te st c ircui t, Figure 6. Vm = 36V, VCC = 5V, VR = 5V, TA = 0°C to 70°C,
unless otherwis e stat ed , TA = TJ.)

PARAMETERS TEST CONDITIONS MIN TYP MAX UNITS

Supply Voltage, Vm (Pins 3, 14) 10 46 V
Logic Supply Voltage, V

CC

(Pin 6) 4.75 5.25 V

Logic Supply Current, I

CC

(Pin 6) IO = I1 = 0 7 15 mA

Thermal Shutdown Temperature +160 +180 °C

Logic Inputs

Input Low Voltage, (Pins 7, 8, 9) 0.8 V
Input High Voltage, (Pins 7, 8, 9) 2 V

CC

V

Low Voltage Input Current, (Pins 7, 8, 9) V

I

= 0.4V, Pin 8 -100

µ

A

V

I

= 0.4V, Pins 7 and 9 -400 mA

High Voltage Input Current, (Pins 7, 8, 9) V

I

= 2.4V 10

µ

A

Comparators

Comparator Low, Thres ho ld Volt ag e (Pin 10) V

R

= 5V; IO = L; I1 = H 668090mV

Comparator Medium, Threshold Voltage (Pin 10) V

R

= 5V; IO = H; I1 = L 236 250 266 mV

Comparator High, Thre sh ol d Vol ta ge (Pin 10 ) V

R

= 5V; IO = L; I1 = L 396 420 436 mV

Comparator Input, Current (Pin 10)

±

20

µ

A

Cutoff Time, t

OFF

RT = 56kΩ, CT = 820pF 25 35

µ

s

Turn Off Delay, t

D

(See Figure 5) 2

µ

s

Source Diode-Transistor Pair

Saturation Voltage, V

SAT

(Pins 1, 15) Im = -0.5A, Conduction Period 1.7 2.1 V

(See Figure 5) I

m

= -0.5A, Recirculation Period 1.1 1.35 V

Saturation Voltage, V

SAT

(Pins 1, 15) Im = -1A, Conduction Period 2.1 2.8 V

(See Figure 5) I

m

= -1A, Recirculation Period 1.7 2.5 V

Leakage Current V

m

= 40V 300

µ

A

Diode Forward Voltage, V

F

Im = -0.5A 1 1.25 V
I

m

= -1A 1.3 1.7 V

2

Figure 1. Typical Source Saturation Voltage

vs Output Current (Recirculation Period)

Figure 2. Typical Source Saturation Voltage

vs Output Current (Conduction Period)

UC3717A

PARAMETERS TEST CONDITIONS MIN TYP MAX UNITS

Sink Diode-Transistor Pair

Saturation Voltage, V

SAT

(Pins 1, 15) Im = 0.5A 0.8 1.1 1.35 V

I

m

= 1A 1.6 2.3 V

Leakage Current V

m

= 40V 300

µ

A

Diode Forward Voltage, V

F

Im = 0.5A 1.1 1.5 V
I

m

= 1A 1.4 2 V

ELECTRICAL
CHARACTERISTICS (cont.)

(Refer to the te st c ircui t, Figure 6. VM = 36V, VCC = 5V, VR = 5V, TA = 0°C to 70°C, unless
otherwise stated, TA = TJ.)

Figure 3. Typical Sink Saturation

Voltage vs Output Current

Figure 4. Typical Power Dissipation

vs Output Current

Figure 5. Typical Waveforms with MA Regulating

(phase = 0)

3