UNITRODE UC1717, UC2717, UC3717 Technical data

Loading...

UC1717

UC1717

UC2717

UC3717

Stepper Motor Drive Circuit

FEATURES

Half-step and Full-step Capability

Bipolar Constant Current Motor Drive

Built-in Fast Recovery Schottky Commutating Diodes

Wide Range of Current Control 5-1000mA

Wide Voltage Range 10-45V

Designed for Unregulated Motor Supply Voltage

Current Levels can be Selected in Steps or Varied Continuously

Thermal Overload Protection

DESCRIPTION

The UC3717 has been designed to control and drive the current in one winding of a bipolar stepper motor. The circuit consists of an LS- TTL-compatible logic input, a current sensor, a monostable and an output stage with built-in protection diodes. Two UC3717s and a few external components form a complete control and drive unit for LSTTL or micro-processor controlled stepper motor systems.

The UC1717 is characterized for operation over the full military temperature range of -55°C to +125°C, the UC2717 is characterized for -25°C to +85°C, and the UC3717 is characterized for 0°C to +70°C.

ABSOLUTE MAXIMUM RATINGS (Note 1)

Voltage

Logic Supply, VCC . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

7V

Output Supply, VM . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

45V

Input Voltage

 

Logic Inputs (Pins 7, 8, 9). . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

6V

Analog Input (Pin 10) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

Vcc

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) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . ±1A Junction Temperature, TJ . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . +150°C Storage Temperature Range, TS . . . . . . . . . . . . . . . . . . -55°C to +150°C

Note 1: All voltages are with respect to ground, Pins 4,5, 12, 13. Pin numbers refer to DIL-16 package. Currents are positive into, negative out of the specified terminal.

Note 2: Consult Packaging Section of Databook for information on thermal limitations and considerations of package.

BLOCK DIAGRAM

7/95

 

 

 

 

 

 

 

UC1717

 

 

 

 

 

 

 

UC2717

CONNECTION DIAGRAMS

 

 

 

 

 

 

UC3717

 

 

 

 

 

 

 

 

DIL-16 (TOP VIEW)

 

 

 

PLCC-20 (TOP VIEW)

PACKAGE PIN FUNCTION

 

 

 

FUNCTION

 

PIN

J or N Package

 

 

 

Q Package

 

 

 

 

N/C

 

 

1

 

 

 

 

 

 

 

 

 

 

 

 

BOUT

 

 

2

 

 

 

 

 

Timing

 

3

 

 

 

 

 

VM

 

 

4

 

 

 

 

 

Gnd

 

 

5

 

 

 

 

 

N/C

 

 

6

 

 

 

 

 

Gnd

 

 

7

 

 

 

 

 

VCC

 

 

8

 

 

 

 

 

I1

 

 

9

 

 

 

 

 

Phase

 

 

10

 

 

 

 

 

N/C

 

 

11

 

 

 

 

 

I0

 

 

12

 

 

 

 

 

Current

 

13

 

 

 

 

 

VR

 

 

14

 

 

 

 

 

Gnd

 

 

15

 

 

 

 

 

N/C

 

 

16

 

 

 

 

 

Gnd

 

 

17

 

 

 

 

 

Vm

 

 

18

 

 

 

 

 

AOUT

 

 

19

 

 

 

 

 

Emitters

 

20

RECOMMENDED OPERATING CONDITIONS

 

 

 

 

 

 

PARAMETER

MIN

TYP

MAX

UNITS

 

 

 

 

Supply Voltage, VCC

4.75

5

5.25

V

 

 

 

 

Supply Voltage, VM

10

 

40

V

 

 

 

 

Output Current. IM

20

 

800

mA

 

 

 

 

Rise Time Logic Inputs, tR

 

 

2

ms

 

 

 

 

Fall Time Logic Inputs, tF

 

 

2

ms

 

 

 

 

Ambient Temperature, TA

 

 

 

 

 

 

 

 

UC1717

-55

 

125

°C

 

 

 

 

UC2717

-25

 

85

°C

 

 

 

 

UC3717

0

 

70

°C

 

 

 

 

ELECTRICAL CHARACTERISTICS Unless otherwise specified, these specifications apply for VCC = 5V, TA = TJ.

 

PARAMETER

 

 

TEST CONDITIONS

MIN

TYP

MAX

UNITS

Supply Current, ICC

 

 

 

 

 

 

25

mA

High-Level Input Voltage, Pins 7, 8, 9

 

 

 

 

2.0

 

 

V

Low-Level Input Voltage, Pins 7, 8, 9

 

 

 

 

 

 

0.8

V

High-Level Input Current, Pins 7, 8, 9

VI = 2.4V

 

 

 

 

20

mA

Low Level Input Current, Pins 7, 8, 9

VI = 0.4V

 

 

-0.4

 

 

mA

Comparator Threshold Voltage

IO = 0, I1 = 0, VR = 5.0V

390

420

440

mV

 

IO = 1, I1 = 0, VR = 5.0V

230

250

270

mV

 

IO = 0, I1 = 1, VR = 5.0V

65

80

90

mV

Comparator Input Current

 

 

 

 

-20

 

20

mA

Output Leakage Current

IO = 1, I1 = 1, TA = +25°C

 

 

100

mA

Total Saturation Voltage Drop

IM = 500mA

 

 

 

 

4.0

V

Total Power Dissipation

IM = 500mA, fS = 30kHz

 

1.4

2.1

W

 

IM = 800mA, fS = 30kHz

 

2.9

3.1

W

Cut Off Time, tOFF

VM = 10V, tON³ 5ms (See Figure 5 and 6)

25

30

35

ms

Turn Off Delay, tD

TA = +25°C; dVc/dt ³ 50mV/ms (See Figure 5 and 6)

 

1.6

2.0

ms

Thermal Shutdown Junction Temperature

 

 

 

+160

 

+180

°C

2

UNITRODE UC1717, UC2717, UC3717 Technical data

UC1717

UC2717

UC3717

Figure 1

Figure 2: Typical Source Saturation Voltage vs Output Current

FUNCTIONAL DESCRIPTION

The UC3717 drive circuit shown in the block diagram includes the following functions:

(1)Phase Logic and H-Bridge Output Stage

(2)Voltage Divider with three Comparators for current control

(3)Two Logic inputs for Digital current level select

(4)Monostable for off time generation

Input Logic: If any of the logic inputs are left open, the circuit will treat it as a high level input.

Phase Input: The phase input terminal, pin 18, controls the direction of the current through the motor winding. The Schmidt-Trigger input coupled with a fixed time delay assures noise immunity and eliminates cross conduction in the output stage during phase changes. A low level on the phase input will turn Q2 on and enable Q3 while a high level will turn Q1 on and enable Q4. (See Figure 7).

Output Stage: The output stage consists of four Darlington transistors and associated diodes connected in an H-Bridge configuration. The diodes are needed to provide a current path when the transistors are being switched. For fast recovery, Schottky diodes are used

Figure 3: Typical Sink Saturation Voltage vs Output Current

Figure 4: Typical Power Losses vs Output Current

Figure 5: Connections and Component Values as in Figure 6.

across the source transistors. The Schottky diodes allow the current to circulate through the winding while the sink transistors are being switched off. The diodes across the sink transistors in conjunction with the Schottkys provide the path for the decaying current during phase reversal. (See Figure 7).

PHASE INPUT

Q1, Q4

Q2, Q3

Low

Off

On

High

On

Off

3

+ 6 hidden pages