Anaheim Stepper AA2920 Users Guide

							AA2920A
BILEVEL STEP MOTOR DRIVER
CONTROLLER HYBRID CIRCUIT
910 E. ORANGEFAIR LANE
ANAHEIM, CA 92801
(714) 992-6990
FAX (714) 992-0471
http://www.anaheimautomation.com
email: [email protected]
October, 1997  #L010008COPYRIGHT
Copyright 1997 by Anaheim Automation.  All rights reserved.  No part of this
publication may be reproduced, transmitted, transcribed, stored in a retrieval
system, or translated into any language, in any form or by any means, electronic,
mechanical, magnetic, optical, chemical, manual, or otherwise, without the prior
written permission of Anaheim Automation, 910 E. Orangefair Lane, Anaheim, CA
92801.
DISCLAIMER
Though every effort has been made to supply complete and accurate information
in this manual, the contents are subject to change without notice or obligation to
inform the buyer.  In no event will Anaheim Automation be liable for direct, indirect,
special, incidental, or consequential damages arising out of the use or inability to
use the product or documentation.  
LIMITED WARRANTY
All Anaheim Automation products are warranted against defects in workmanship,materials and construction, when used under Normal Operating Conditions and
when used in accordance with specifications.  This warranty shall be in effect for a
period of twelve months from the date of purchase or eighteen months from the
date of manufacture, whichever comes first.  Warranty provisions may be voided
if the products are subjected to physical damage or abuse.
Anaheim Automation will repair or replace at its option, any of its products which
have been found to be defective and are within the warranty period, provided thatthe item is shipped freight prepaid, with RMA (return material authorization), to
Anaheim Automations plant in Anaheim, California. 
						

							12 TABLE OF CONTENTSDESCRIPTION
DESCRIPTION...............................................2
PACKAGE INFORMATION.....................................2
SPECIFICATIONS............................................3
BILEVEL DRIVE OPERATION..................................5
PIN DESCRIPTION...........................................6
CLOCK INPUT SELECTION...................................10
HALF-STEP/FULL-STEP......................................12The AA2920 is a CMOS integrated circuit based hybrid step motor driver ideallysuited for the design of 4-phase unipolar bilevel step motor drivers.  This hybrid can
be used to design half-step and full-step bilevel type drivers.
The basic function of this hybrid is to take input (i.e. clock and direction) signals and
turn them into appropriate phase signals that are used to drive output transistors.
In most applications, the end user simply adds a few components along with power
transistors for the output stage. This results in low cost, compact, and reliable
designs.
The AA2920 comes in a 34-pin hybrid package.  Dimensions below are in inches. 
						

							34 SPECIFICATIONSAA2820 OUTPUT CHARACTERISTICS
PARAMETERSYMBOLLIMITSUNITS
MINTYP.MAX
Supply VoltageVdd4.755.005.25V
Input Logic High (Vdd=5.0V)Vih3.5VddV
Input Logic Low (Vdd=5.0V)Vil00.8V
Operating Temperature (Ambient)Ta0-70 C
Storage TemperatureTs0-70 C
Power Dissipation250mW
Supply current50mA
Min. clock Pulse Widthtwh, twl15usec
Propagation Delay Time tpd3.55usec
(Clock to Output )
Figure 3: Input/Output Waveform Characteristics 
						

							56 Figure 4:  High Voltage Output (OUT5) vs. Reset
(R13) and OUT1.BILEVEL DRIVEAA2920A PIN DESCRIPTION
The basic function of a step motor driver is to control the motor winding currents.PINNAMEDESCRIPTIONMotor performance is determined by how fast the driver can increase and decrease
the winding currents. A rapid rise in winding current is achieved by applying a high1VddPower (+5Vdc)
voltage directly to a motor.  This rapid rise of current is also referred to as the kick
or operating current.  When a desired current level is reached, a low voltage is2VHVDriver High Voltage 
applied to maintain a suitable holding current level.  When a motor winding is
turned off, a rapid decrease in winding current is achieved by routing the energy in
the collapsing field back to the power supply through a high voltage path.  The high3B24Base Output for High Voltage Darlington Transistor.
voltage supply furnishes the energy necessary to maintain motor output torque at( Phase 2 and Phase 4)
high step rates thus providing high mechanical power output.  The low voltage
supply provides much of the current needed at low step rates and all of the holding4E24Emitter Output for High Voltage Darlington Transistor.
current.  ( Phase 2 and Phase 4)
The efficiency of the bilevel drive makes for step motor performance that is far5B13Base Output for High Voltage Darlington Transistor.
superior to that produced by L/R drives.  Also, bilevel drivers do not use high( Phase 1 and Phase 3)
frequency switching techniques as chopper drivers do.  Consequently, they do not
create the EMI, RFI, and motor heating problems that are associated with chopper6E13Emitter Output for High Voltage Darlington Transistor.
drivers.( Phase 1 and Phase 3)
AA2920A Operation7HV OFFGrounding this pin will disable the High Voltage.
Each time the AA2920 receives a clock signal, the phase outputs change state.
When a phase output turns on, a high voltage output also turns on.  This high
voltage output is used to turn on a high-side switch.  The high voltage output will8Reg AResistor Network Useful in producing an external 5Vdc   
stay on until the chip gets a reset signal.  In Figure 4, OUT1 turns on when the                       supply with a LM317 Voltage Regulator.
CLOCK input goes low.  OUT5 turns on at the same time.  OUT5 stays on until the
reset input, R13 goes low.  The waveforms in Figure 4 are for half-step operation.91B01  Base Driver for Phase 1 (Output  Impedence of 500
In half-step operation, the phase outputs are on for three clock cycles.  The highOhms.) 
voltage output will turn on the first two of these cycles.  If the reset input never goes
low, the high voltage output will stay on.  In full-step operation, each phase output102B01Base Driver for Phase 1 (Output  Impedence of 150
is on for two clock cycles and the corresponding high voltage output will turn on atOhms.) 
the beginning of each clock cycle.
111B03Base Driver for Phase 3 (Output  Impedence of 500
Ohms.) 
122B03Base Driver for Phase 3 (Output  Impedence of 150
Ohms.) 
131B02Base Driver for Phase 2 (Output  Impedence of 500
Ohms.)  
						

							78 AA2920A PIN DESCRIPTION (cont)AA2920A PIN DESCRIPTION (cont)
PINNAMEDESCRIPTION142B02Base Driver for Phase 2 (Output  Impedence of 150PINNAMEDESCRIPTIONOhms.) 
151B04Base Driver for Phase 4 (Output  Impedence of 500
Ohms.) 
27(03IN)DIR.Phase 3 in Phase Mode or Direction Control for clockwise
162B04Base Driver for Phase 4 (Output  Impedence of 150
Ohms.) 
17Vss0VdcDown).Note this pin is also the Test Point for the Internal
18Vss0Vdc
selection for Counter Clock Wise motion.
19POTLS Kick Current Potentiometer Low Side.
20R24Sense Resistor Input for Phase 2 and Phase 4.with Phase Mode or Input Polarity for Negative and
(Signal feeds into Comparator of Phase 2 and Phase 4)Positive Polarity in Clock and Direction Mode.
21POTCOM Kick Current Potentiometer Common (Wiper).
22R13Sence Resistor Input for Phase 1 and Phase 3.
(Signal feeds into Comparator of Phase 1 and Phase 3)
23POTHS Kick Current Potentiometer High Side.
24ON/OFFEnables Driver Output (Pulled High) and Disables DriverOutputs when Pulled Down.
Outputs (Pulled Low).
25(04IN)HS/FSPhase 4 in Phase Mode or Enables Half-Step(Pulled High)
and Full-Step(Pulled Down) in Clock and Direction Mode.26R2527Pull-Up or Pull-Down Resistors used in conjunction with
with Phase Mode or Clock and Direction Mode. 
and counter clockwise motion selection.
28C/P(OSCOUT)Selects Clock Mode (Pulled Up) or  Phase Mode(Pulled
Oscillator = 1MegHz ±10%.
29(02IN)CCWPhase 2 in Phase Mode or Clock Input in Two Clock Mode
30R2931(IP)Pull-Up or Pull-Down Resistors used in conjunction with
31(01IN)CLOCKPhase 1 in Phase Mode or Clock Input in Clock and
Direction Mode.
32Step OutStep Clock Output 
33RUN/STOPEnables Outputs (Pulled High) when running and Disables
34VddPower (+5Vdc) 
						

							910 CLOCK INPUT SELECTION
There are three three clocking methods for the and AA2920A.  The C/P input is
used to select CLOCK inputs or PHASE inputs.  The IP input is used to select
positive or negative going inputs.  See Table 1.
INPUT CLOCK SELECTIONC/PIP
+ GOING CLOCK INPUTS10
- GOING CLOCK INPUTS11
POSITIVE TRUE PHASE INPUTS00
NEGATIVE TRUE PHASE INPUTS01
 TABLE 1:  Clock Input Selection.
CLOCK and DIRECTION:  Pulses applied to the CLOCK input will cause the motor
to step in the clockwise direction if the DIRECTION input is logic 1.  Pulses
applied to the CLOCK input will cause the motor to step in the counterclockwise
direction if the DIRECTION input is logic 0.  Figure 7 shows Clock and Direction
signals which will make 5 steps in the clockwise direction and 5 steps in the
counterclockwise direction.
CLOCK and CCW:  Pulses applied to the CLOCK input cause the motor to step in
the clockwise direction.  Pulses applied to the CCW input cause the motor to step
in the counterclockwise direction.  Pulses should NOT be applied to both of these
inputs at the same time.  The input which is not being used should be held low when
using positive going clock inputs, or held high when using negative going clock
inputs.  Figure 7 shows Clock and Direction signals which will make 5 steps in the
clockwise direction and 5 steps in the counterclockwise direction.
PHASE INPUTS:  Half-step or Full-step sequence phase inputs may be used to
synchronize multiple axes.  Only the phase input sequences shown in Figure 8 may
be used.  The phase input sequences in Figure 8 produce clockwise motor
movement.  The phases may be reversed to obtain counterclockwise motor
movement.  Positive or Negative true phase inputs may be used.Figure 8:  Phase Input Sequence Figure 7:  The CLOCK and DIRECTION signals are
equivalent to the CW and CCW signals 
						

							HALF-STEP/FULL-STEP
The AA2920A operates  a motor in either half-step or full-step operation.  In half-
step mode, the motor is stepped by alternately energizing one phase, and then two
phases of  the motor.  With a 1.8 degree motor (200 steps/rev), half-step mode will
provide 400 steps/revolution.  Table 2 below shows the sequence for half-step.
PHASE 1PHASE 2PHASE 3PHASE 4
CCW
 
CW 1000
1100
0100
0110
0010
0011
0001
1001
 Table 2:  Half-step Phase Sequence   1=ON, 0=OFF
In Full-step mode, there are always two phases on at a time.  The motor is stepped
by turning off a phase and turning on the opposite phase (i.e. - turn phase 1 off and
turn phase 3 on).  A standard 1.8 degree motor will provide 200 steps/revolution in
full-step mode.  The phase sequence for full-step is shown in figure y2.
PHASE 1PHASE 2PHASE 3PHASE 4
CCW
 
CW 1100
0110
0011
1001
Table 3:  Full-step Phase Sequence    1=ON, 0=OFFNOTES 
						

							NOTES
910 E. Orangefair Lane
Anaheim, CA 92801
(714) 992-6990
fax (714) 992-0471