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Stepper Motor Controllers - Lecture Notes | ECE 441, Exams of Electrical and Electronics Engineering

Oregon State University (OSU)Electrical and Electronics Engineering

Material Type: Exam; Class: ENGINEERING DESIGN PROJECT; Subject: Electrical & Computer Engineer; University: Oregon State University; Term: Fall 2006;

Typology: Exams

Pre 2010

Uploaded on 08/30/2009

koofers-user-4ld 🇺🇸

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®

L297

STEPPER MOTOR CONTROLLERS

NORMAL/WAVE DRIVE

HALF/FULL STEP MODES

CLOCKWISE/ANTICLOCKWISE DIRECTION

SWITCHMODE LOAD CURRENT REGULA-

TION

PROGRAMMABLE LOAD CURRENT

FEW EXTERNAL COMPONENTS

RESET INPUT & HOME OUTPUT

ENABLE INPUT

DESCRIPTION

The L297 Stepper Motor Controller IC generates

four phase drive signals for two phase bipolar and

four phase unipolar step motors in microcomputer-

controlled applications. The motor can be driven in

half step, normal and wawe drive modes and on-

chip PWM chopper circuits permit switch-mode

control of the current in the windings. A feature of

December 2001

Symbol Parameter Value Unit

VsSupply voltage 10 V

ViInput signals 7V

P

tot Total power dissipation (Tamb = 70°C) 1W

T

stg, TjStorage and junction temperature -40 to + 150 °C

ABSOLUTE MAXIMUM RATINGS

this device is that it requires only clock, direction

and mode input signals. Since the phase are gen-

erated internally the burden on the microprocessor,

and the programmer, is greatly reduced. Mounted

in DIP20 and SO20 packages, the L297 can be

used with monolithic bridge drives such as the

L298N or L293E, or with discrete transistors and

darlingtons.

TWO PHASE BIPOLAR STEPPER MOTOR CONTROL CIRCUIT

DIP20 SO20

ORDERING NUMBERS : L297/1 (DIP20)

L297D (SO20)

1/11

Discover Exams of Electrical and Electronics Engineering Oregon State University (OSU)

Partial preview of the text

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® L

STEPPER MOTOR CONTROLLERS

NORMAL/WAVE DRIVE

HALF/FULL STEP MODES

CLOCKWISE/ANTICLOCKWISE DIRECTION

SWITCHMODE LOAD CURRENT REGULA-

TION

PROGRAMMABLE LOAD CURRENT

FEW EXTERNAL COMPONENTS

RESET INPUT & HOME OUTPUT

ENABLE INPUT

DESCRIPTION

The L297 Stepper Motor Controller IC generates

four phase drive signals for two phase bipolar and

four phase unipolar step motors in microcomputer-

controlled applications. The motor can be driven in

half step, normal and wawe drive modes and on-

chip PWM chopper circuits permit switch-mode

control of the current in the windings. A feature of

December 2001

Symbol Parameter Value Unit Vs Supply voltage 10 V Vi Input signals 7 V Ptot Total power dissipation (Tamb = 70°C) 1 W Tstg, T (^) j Storage and junction temperature -40 to + 150 (^) °C

ABSOLUTE MAXIMUM RATINGS

this device is that it requires only clock, direction

and mode input signals. Since the phase are gen-

erated internally the burden on the microprocessor,

and the programmer, is greatly reduced. Mounted

in DIP20 and SO20 packages, the L297 can be

used with monolithic bridge drives such as the

L298N or L293E, or with discrete transistors and

darlingtons.

TWO PHASE BIPOLAR STEPPER MOTOR CONTROL CIRCUIT

DIP20 SO

ORDERING NUMBERS : L297/1 (DIP20)L297D (SO20)

PIN CONNECTION (Top view)

BLOCK DIAGRAM (L297/1 - L297D)

L297/ L297D

N ° NAME FUNCTION

19 HALF/FULL Half/full step select input. When high selects half step operation,when low selects full step operation. One-phase-on full step mode is obtained by selecting FULL when the L297’s translator is at aneven-numbered state. Two-phase-on full step mode is set by selecting FULL when thetranslator is at an odd numbered position. (The home position is designate state 1). 20 RESET Reset input. An active low pulse on this input restores thetranslator to the home position (state 1, ABCD = 0101).

PIN FUNCTIONS - L297/1 - L297D (continued)

CIRCUIT OPERATION

The L297 is intended for use with a dual bridge

driver, quad darlington array or discrete power

devices in step motor driving applications. It re-

ceives step clock, direction and mode signals from

the systems controller (usually a microcomputer

chip) and generates control signals for the power

stage.

The principal functions are a translator, which gen-

erates the motor phase sequences, and a dual

PWM chopper circuit which regulates the current in

the motor windings. The translator generates three

different sequences, selected by the HALF/FULL

input. These are normal (two phases energised),

wave drive (one phase energised) and half-step

(alternately one phase energised/two phases en-

ergised). Two inhibit signals are also generated by

the L297 in half step and wave drive modes. These

signals, which connect directly to the L298’s enable

inputs, are intended to speed current decay when

a winding is de-energised. When the L297 is used

to drive a unipolar motor the chopper acts on these

lines.

An input called CONTROL determines whether the

chopper will act on the phase lines ABCD or the

inhibit lines INH1 and INH2. When the phase lines

are chopped the non-active phase line of each pair

(AB or CD) is activated (rather than interrupting the

line then active). In L297 + L298 configurations this

technique reduces dissipation in the load current

sense resistors.

A common on-chip oscillator drives the dual chop-

per. It supplies pulses at the chopper rate which set

the two flip-flops FF1 and FF2. When the current in

a winding reaches the programmed peak value the

voltage across the sense resistor (connected to

one of the sense inputs SENS 1 or SENS 2 ) equals

Vref and the corresponding comparator resets its

flip flop, interrupting the drive current until the next

oscillator pulse arrives. The peak current for both

windings is programmed by a voltage divider on the

Vref input.

Ground noise problems in multiple configurations

can be avoided by synchronising the chopper os-

cillators. This is done by connecting all the SYNC

pins together, mounting the oscillator RC network

on one device only and grounding the OSC pin on

all other devices.

Symbol Parameter DIP20 SO20 Unit R (^) th-j-amb Thermal resistance junction-ambient max (^80 100) °C/W

THERMAL DATA

MOTOR DRIVING PHASE SEQUENCES

The L297’s translator generates phase sequences

for normal drive, wave drive and half step modes.

The state sequences and output waveforms for

these three modes are shown below. In all cases

the translator advances on the low to high transis-

tion of CLOCK.

Clockwise rotation is indicate; for anticlockwise ro-

tation the sequences are simply reversed RESET

restores the translator to state 1, where ABCD =

HALF STEP MODE

Half step mode is selected by a high level on the HALF/FULL input.

NORMAL DRIVE MODE

Normal drive mode (also called "two-phase-on" drive) is selected by a low level on the HALF/FULL input

when the translator is at an odd numbered state (1, 3, 5 or 7). In this mode the INH1 and INH2 outputs

remain high throughout.

Symbol Parameter Test conditions Min. Typ Max. Unit Ileak Leakage current (pin 3) V (^) CE = 7 V (^1) μA Vsat Saturation voltage (pin 3) I = 5 mA 0.4 V Voff Comparators offset voltage(pins 13, 14, 15) Vref = 1 V 5 mV Io Comparator bias current(pins 13, 14, 15) -100 10 μA Vref Input reference voltage (pin 15) 0 3 V tCLK Clock time 0.5 (^) μs tS Set up time 1 μs t (^) H Hold time 4 μs t (^) R Reset time (^1) μs t (^) RCLK Reset to clock delay (^1) μs

ELECTRICAL CHARACTERISTICS (continued)

Figure 1.

APPLICATION INFORMATION

TWO PHASE BIPOLAR STEPPER MOTOR CONTROL CIRCUIT

This circuit drives bipolar stepper motors with winding currents up to 2A. The diodes are fast 2A types.

Figure 2.

Figure 3 : Synchronising L297s

A

B e

D

E

L

K

H

A1 C

SO20MEC

h x 45˚

SO

DIM. mm^ inch MIN. TYP. MAX. MIN. TYP. MAX. A 2.35 2.65 0.093 0. A1 0.1 0.3 0.004 0. B 0.33 0.51 0.013 0. C 0.23 0.32 0.009 0. D 12.6 13 0.496 0. E 7.4 7.6 0.291 0. e 1.27 0. H 10 10.65 0.394 0. h 0.25 0.75 0.010 0. L 0.4 1.27 0.016 0. K 0˚ (min.)8˚ (max.)

OUTLINE AND MECHANICAL DATA

Information furnished is believed to be accurate and reliable. However, STMicroelectronics assumes no responsibility for the consequences ofuse of such information nor for any infringement of patents or other rights of third parties which may result from its use. No license is granted by implication or otherwise under any patent or patent rights of STMicroelectronics. Specification mentioned in this publication are subject tochange without notice. This publication supersedes and replaces all information previously supplied. STMicroelectronics products are not authorized for use as critical components in life support devices or systems without express written approval of STMicroelectronics. The ST logo is a registered trademark of STMicroelectronics © 2001 STMicroelectronics – Printed in Italy – All Rights Reserved STMicroelectronics GROUP OF COMPANIES Australia - Brazil - Canada - China - Finland - France - Germany - Hong Kong - India - Israel - Italy - Japan - Malaysia - Malta - Morocco -Singapore - Spain - Sweden - Switzerland - United Kingdom - United States. http://www.st.com

Stepper Motor Controllers - Lecture Notes | ECE 441, Exams of Electrical and Electronics Engineering

Related documents

Partial preview of the text

Download Stepper Motor Controllers - Lecture Notes | ECE 441 and more Exams Electrical and Electronics Engineering in PDF only on Docsity!

® L

STEPPER MOTOR CONTROLLERS

NORMAL/WAVE DRIVE

HALF/FULL STEP MODES

CLOCKWISE/ANTICLOCKWISE DIRECTION

SWITCHMODE LOAD CURRENT REGULA-

TION

PROGRAMMABLE LOAD CURRENT

FEW EXTERNAL COMPONENTS

RESET INPUT & HOME OUTPUT

ENABLE INPUT

DESCRIPTION

The L297 Stepper Motor Controller IC generates

four phase drive signals for two phase bipolar and

four phase unipolar step motors in microcomputer-

controlled applications. The motor can be driven in

half step, normal and wawe drive modes and on-

chip PWM chopper circuits permit switch-mode

control of the current in the windings. A feature of

ABSOLUTE MAXIMUM RATINGS

this device is that it requires only clock, direction

and mode input signals. Since the phase are gen-

erated internally the burden on the microprocessor,

and the programmer, is greatly reduced. Mounted

in DIP20 and SO20 packages, the L297 can be

used with monolithic bridge drives such as the

L298N or L293E, or with discrete transistors and

darlingtons.

TWO PHASE BIPOLAR STEPPER MOTOR CONTROL CIRCUIT

DIP20 SO

ORDERING NUMBERS : L297/1 (DIP20)L297D (SO20)

PIN CONNECTION (Top view)

BLOCK DIAGRAM (L297/1 - L297D)

N ° NAME FUNCTION

PIN FUNCTIONS - L297/1 - L297D (continued)

CIRCUIT OPERATION

The L297 is intended for use with a dual bridge

driver, quad darlington array or discrete power

devices in step motor driving applications. It re-

ceives step clock, direction and mode signals from

the systems controller (usually a microcomputer

chip) and generates control signals for the power

stage.

The principal functions are a translator, which gen-

erates the motor phase sequences, and a dual

PWM chopper circuit which regulates the current in

the motor windings. The translator generates three

different sequences, selected by the HALF/FULL

input. These are normal (two phases energised),

wave drive (one phase energised) and half-step

(alternately one phase energised/two phases en-

ergised). Two inhibit signals are also generated by

the L297 in half step and wave drive modes. These

signals, which connect directly to the L298’s enable

inputs, are intended to speed current decay when

a winding is de-energised. When the L297 is used

to drive a unipolar motor the chopper acts on these

lines.

An input called CONTROL determines whether the

chopper will act on the phase lines ABCD or the

inhibit lines INH1 and INH2. When the phase lines

are chopped the non-active phase line of each pair

(AB or CD) is activated (rather than interrupting the

line then active). In L297 + L298 configurations this

technique reduces dissipation in the load current

sense resistors.

A common on-chip oscillator drives the dual chop-

per. It supplies pulses at the chopper rate which set

the two flip-flops FF1 and FF2. When the current in

a winding reaches the programmed peak value the

voltage across the sense resistor (connected to

one of the sense inputs SENS 1 or SENS 2 ) equals

Vref and the corresponding comparator resets its

flip flop, interrupting the drive current until the next

oscillator pulse arrives. The peak current for both

windings is programmed by a voltage divider on the