ELM312DSB [ELM]

STEPPER MOTOR CONTROLLER; 步进电机控制器


型号：	ELM312DSB
厂家：	ELM ELECTRONICS
描述：	STEPPER MOTOR CONTROLLER 步进电机控制器电动机控制电机控制器
文件：	总5页 (文件大小：35K)
中文：	中文翻译
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ELM312

Stepper Motor Controller

Description

Features

The ELM312 is an interface circuit for use

• Low power CMOS design - typically 1mA at 5V

• Wide supply range - 3.0 to 5.5 volt operation

• Two inputs control Half step motion

between high speed logic and four phase stepper

motor driver circuits. All of the logic required to

provide stepping in two directions is contained in this

one 8 pin package.

• No external timing components

• Completely static operation - will maintain a step

position indefinitely

This circuit supports only the half-step mode of

operation. This mode provides eight distinct phase

control output signals for driving a variety of motors.

For dual mode operation, the ELM310 should be

considered.

• High current drive outputs - up to 25 mA

• Very high speed - up to 25000 steps per second

The ELM312 can be controlled by a wide variety

of circuits, due to its fully static operation. In addition

to using high speed microprocessor control, suitably

debounced mechanical switches or continuously

running oscillator circuits could also be used.

Connection Diagram

PDIP and SOIC

(top view)

Applications

VDD

VSS

• Stepper motor drive logic

• Process sequencing

Dir

• Sequential left/right LED driver

Step

Block Diagram

20msec

Startup

Timer

Inhibit

Dir

Step

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ELM312

Pin Descriptions

VDD (pin 1)

Step (pin 4)

This pin is the positive supply pin, and should

always be the most positive point in the circuit.

Internal circuitry connected to this pin is used to

provide power on reset of the microprocessor, so

an external reset signal is not required. Refer to

the Electrical Characteristics section for further

information.

This input is used to control the motion of the

motor. Outputs will change to their next state on

the high to low transition of this input. Step is

normally maintained at a low level, and is only

brought high then low to cause a step to occur.

The Step input is ignored for about 20ms after

power-up to allow sufficient time for external

circuits to stabilize.

A (pin 2)

D (pin 5)

This is the active high output drive signal for the

(first) phase A winding. Normally, this output

would be the first to be energized when starting a

stepping sequence, and is always the first state

entered into internally on powerup. After powerup,

however, the ELM312 treats this pin specially,

maintaining it at a low level until the first step

command is received. This in effect keeps the

motor off until selected by control circuitry.

This is the active high output drive signal for the

(fourth) phase D winding.

C (pin 6)

This is the active high output drive signal for the

(third) phase C winding.

B (pin 7)

This is the active high output drive signal for the

(second) phase B winding.

Dir (pin 3)

This pin determines the sequence that the outputs

will be energized in. A high input on the Dir pin

while the step input is pulsed will cause a single

clockwise step, while a low level will cause a

counter-clockwise step. (Refer to Figures 1 & 2).

VSS (pin 8)

Circuit common is connected to this pin. This is

the most negative point in the circuit.

Dir must be at a stable level prior to the low to

high transition of Step in order to be recognized

(refer to the Tsu specification).

Ordering Information

These integrated circuits are available in either the 300 mil plastic DIP format, or in the 200 mil SOIC surface

mount type of package. To order, add the appropriate suffix to the part number:

300 mil Plastic DIP............................... ELM312P

200 mil SOIC..................................... ELM312SM

Every effort is made to verify the accuracy of information provided in this document, but no representation or warranty can be

given and no liability assumed by Elm Electronics with respect to the accuracy and/or use of any products or information

described in this document. Elm Electronics will not be responsible for any patent infringements arising from the use of these

products or information, and does not authorize or warrant the use of any Elm Electronics product in life support devices and/or

systems. Elm Electronics reserves the right to make changes to the device(s) described in this document in order to improve

reliability, function, or design.

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ELM312

Absolute Maximum Ratings

Storage Temperature....................... -65°C to +150°C

Note:

Stresses beyond those listed here will likely damage

the device. These values are given as a design

guideline only. The ability to operate to these levels

is neither inferred nor recommended.

Ambient Temperature with

Power Applied....................................-40°C to +85°C

Voltage on VDD with respect to VSS............0 to +7.5V

Voltage on any other pin with

respect to VSS........................... -0.6V to (VDD + 0.6V)

Electrical Characteristics

All values are for operation at 25°C and a 5V supply, unless otherwise noted. For further information, refer to note 1 below.

Characteristic

Minimum Typical

Maximum Units

Conditions

Supply Voltage, VDD

VDD rate of rise

3.0

5.0

5.5

V/ms

see note 2

VDD = 5V

0.05

Average Supply Current, IDD

Input low voltage

1.0

2.4

0.15 VDD

VDD

see note 3

VSS

Input high voltage

Output low voltage

Output high voltage

0.85 VDD

0.6

Current (sink) = 8.7mA

VDD - 0.7

Current (source) = 5.4mA

Direction Input Setup Time (Tsu)

Hold Time (Th)

see note 4

µsec

see note 4

see note 5

Step Pulse Width (Tp)

Delay Between Steps (Td)

Step Inhibit on Power-up

Notes:

µsec

msec

1. This integrated circuit is produced with a Microchip Technology Inc.’s PIC12C5XX as the core embedded

microcontroller. For further device specifications, and possibly clarification of those given, please refer to the

appropriate Microchip documentation.

2. This spec must be met in order to ensure that a correct power on reset occurs. It is quite easily achieved

using most common types of supplies, but may be violated if one uses a slowly varying supply voltage, as

may be obtained through direct connection to solar cells, or some charge pump circuits.

3. This IC is uses CMOS technology so input currents to the logic are negligible. Each input does have internal

diode protection circuits, however, which may cause up to 1µA of leakage currents to flow.

4. Operation of the ELM312 is completely static, so there is no maximum time for any of these parameters.

Each of the values is graphically displayed in Figure 1 on page 4.

5. The Step input will initially be blocked for this time, to allow external circuits time to stabilize.

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ELM312

Timing Diagrams

Step

Dir

Tsu

Figure 1. Circuit Timing

Output Logic Level

Step

Figure 2. Stepping Sequence (Clockwise Direction)

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ELM312

Example Application

Figure 3 shows the ELM312 used in a circuit to

control a four phase stepper motor. The motor shown

here is typical of the type often found in computer disk

drives, and are readily available on the surplus market.

This particular motor requires +12V at 160mA per phase

to operate, and has a resolution of 3.6° per step.

connected from Drain to Source internally. This diode

helps to control inductive kick-back when a winding is de-

energized. Optional resistors (50-100W) are shown in the

circuit to dampen resonances due to wiring inductance

and gate capacitance. They should be used if the

transistors are mounted any more than a few inches from

the ELM312.

Momentary action pushbuttons are used as control

inputs in this case. This allows the user to experiment

with the operation of the motor. An ELM410 is used to

debounce the switches, so that the mechanical

bouncing of the switches does not cause multiple steps

of the motor armature.

Operation of the circuit is straight-forward. The motor

advances one step each time the step button is released.

If the clockwise input is also pressed, the windings will be

energized in the order A-AB-B-BC-C-CD-D-DA. Recall

that when power is first applied, no winding is energized,

to provide a means to sequence the start-up of several

motors in larger systems. For this reason, no output will

appear until the first step command is issued.

Both integrated circuits are powered from a 5 volt

supply, not shown on this diagram. This supply could be

derived from the 12V for the motor, but is not

necessarily, as the user may want to separate the two

due to noise from the motor.

This circuit demonstrates the operation of a stepper

motor, and can easily be modified for further

experimentation. One change that could be made is the

addition of an oscillator in the place of the ELM410, to

provide continuous motion. Another might be the direct

connection of the ELM312 to a computer port for

robotics, and the incorporation of sensors for feedback to

the computer.

The motor is directly driven by IRF511 power

MOSFETS in this design, because they were readily

available, but many other devices would be suitable.

The main criteria, as well as voltage and current

capabilities, is that the MOSFET be fully switched by the

logic signal available (in this case 5V). Some of the

‘logic level’ HEXFETs would be well suited in this case

(IRLZ14 or IRL510 for example).

+12V

The main advantages of power MOSFETs over

bipolar types are their ability to be driven directly from

CMOS logic, and their inherent reverse biased diode

Stepper

Motor

+5V

Clockwise

+5V

* - see text

0.1µF

Step

Figure 3. Manual Control of a Stepper Motor

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ELM312DSB [ELM]

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