Electronic Device And Electronic Circuit

Data of electronic device , PCB Design and electronic circuit

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Friday, January 30, 2009

High Current Microstep Stepper Motor Driver

High Current Microstep Stepper Motor Driver
with protection

The TMC236 / TMC236A (1) is a dual full bridge driver IC for bipolar
stepper motor control applications. It is realized in a HVCMOS
technology combined with Low-RDS-ON high efficiency MOSFETs
(pat. pend.). It allows to drive a coil current of up to 1500mA even at
high environment temperatures. Its low current consumption and high
efficiency together with the miniature package make it a perfect
solution for embedded motion control and for battery powered devices.
The low power dissipation makes the TMC236 an optimum choice for
drives, where a high reliability is desired. Internal DACs allow
microstepping as well as smart current control. The device can be
controlled by a serial interface (SPI™i) or by analog / digital input
signals. Short circuit, temperature, undervoltage and overvoltage
protection are integrated.


• Control via SPI with easy-to-use 12 bit protocol or external
analog / digital signals
• Short circuit, overvoltage and overtemperature protection integrated
• Status flags for overcurrent, open load, over temperature, temperature
pre-warning, undervoltage
• Integrated 4 bit DACs allow up to 16 times microstepping via SPI
(can be expanded to 64 microsteps)
• Any resolution via analog control
• Mixed decay feature for smooth motor operation
• Slope control user programmable to reduce electromagnetic emissions
• Chopper frequency programmable via a single capacitor or external clock
• Current control allows cool motor and driver operation
• Internal open load detector
• 7V to 34V motor supply voltage (A-type)
• Up to 1500mA output current and more than 800mA at 105°C
• 3.3V or 5V operation for digital part
• Low power dissipation via low RDS-ON power stage
• Standby and shutdown mode available

TMC236 Datasheet pdf

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Wednesday, January 28, 2009

Precision Microstepping Driver Circuit

PBM 3960 is a dual 7-bit+sign, Digital-to-Analog Converter (DAC)
Especially developed to be used together with the PBL 3771,
Precision Stepper Motor driver in micro-stepping applications.
The circuit has a set of input registers connected to an 8-bit data port
for easy interfacing directly to a microprocessor. Two registers are
used to store the data for each seven-bit DAC, the eighth bit being a
sign bit (sign/ magnitude coding). A second set of registers are used
for automatic fast/slow current decay control in conjunction with
the PBL 3771, a feature that greatly improves highspeed micro-stepping
performance. The PBM 3960 is fabricated in a high-speed CMOS

Key Features
- Analog control voltages from 3 V down to 0.0 V.
- High-speed microprocessor interface.
- Automatic fast/slow current decay control.
- Full-scale error ±1 LSB.
- Interfaces directly with TTL levels and CMOS devices.
- Fast conversion speed, 3 ms.
- Matches PBL 3771.

PBM 3960 Datasheet pdf

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Monday, January 26, 2009

Microstepping Data

Microstepping of Stepper Motors
Let's now look at what current ratios are needed to produce a particular
step angle. The Microstep angle can be graphically represented with
a Phasor Diagram. (See diagram below) The X and Y axis indicate
the current level in two respective coils A, B. A vector (ray from origin
to coordinate X,Y) shows the resultant angle and Torque (magnitude
of the vector) when some current is applied to both coils. Keep in mind
that this diagram shows the 'sub-angle' between natural whole steps
(poles) of the motors. On a typical 200 step per revolution motor this
is 1.8 degrees. The graph below is a representation of how that angle
can be further sub-divided.


Microstepping Tutorial

If the controller is designed with the capability to control the magnitude
of the current in each winding, then microstepping can be implemented.
The phase diagrams below all show different implementations of "divide
by 4" microstepping. Note that it is the phasor angle (not it's length) that
determines the microstep position.


Stepping Motor Physics
Microstepping allows even smaller steps by using different currents
through the two motor windings

For a two-winding variable reluctance or permanent magnet motor,
assuming nonsaturating magnetic circuits, and assuming perfectly
sinusoidal torque versus position curves for each motor winding

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Friday, January 23, 2009

Variable-reluctance Stepper Motors

Variable-reluctance (VR) Stepper Motors

The variable-reluctance (VR) stepper motor differs from the PM
stepper in that it has no permanent-magnet rotor and no residual
torque to hold the rotor at one position when turned off. When the
stator coils are energized, the rotor teeth will align with the energized
stator poles. This type of motor operates on the principle of minimizing
the reluctance along the path of the applied magnetic field. By
alternating the windings that are energized in the stator, the stator field
changes, and the rotor is moved to a new position.

Variable reluctance stepper

The drive waveforms for the 3-φ stepper can be seen in the
“Reluctance motor” section. The drive for a 4-φ stepper is shown in
Figure . Sequentially switching the stator phases produces a rotating
magnetic field which the rotor follows. However, due to the lesser
number of rotor poles, the rotor moves less than the stator angle for
each step.

Switched Reluctance Motor

switched reluctance (also known as variable reluctance) motor has
no permanent magnets or brushes. Coils connected in series around
a pair of opposite stator poles are energised by a DC current to create
lines of magnetic flux. This causes a pair of teeth on the iron rotor to
align themselves with the stator poles. This sequence is continued around
the stator poles causing the rotor to rotate. Suitable for high torque and
high speed applications

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Tuesday, January 20, 2009

Stepper Motor Data 3

How To Select A Step Motor Driver

A step motor driver provides precisely controllable speed and positioning.
The motor increments a precise amount with each control pulse easily

converting digital information to exact incremental rotation without the
need for feedback devices such as tachometers or encoders. Because
the system is open loop, the problems of feedback loop phase shift and
resultant instability, common with servo drives, are eliminated.
Load characteristics, performance requirements, and mechanical design
including coupling techniques must be thoroughly considered before
the designer can effectively select the most suitable motor and driver
combination for an application.

Torque-angle curves for the stepping motor

(a) permanent-magnet rotor and (b) variable-reluctance rotor.

currents. Reversing the phase currents will cause the rotor to reverse
its orientation. This is in contrast to VRM configuration with
a ferromagnetic rotor, in which two rotor positions are equally stable
for any particular set of phase currents, and hence the rotor position
cannot be determined uniquely. Permanent-magnet stepping motors
are also unlike their VRM counterparts in that torque tending to align
the rotor with the stator poles will be generated even when there is
no excitation applied to the phase windings. Thus the rotor will have
preferred unexcited rest positions, a fact which can be used to advantage
in some applications.


Sunday, January 18, 2009

Stepper Motor Data 2

Types of Stepper Motors
A stepper, or stepping motor converts electronic pulses into
proportionate mechanical movement. Each revolution of
the stepper motor's shaft is made up of a series of discrete individual
steps. A step is defined as the angular rotation produced by the output
shaft each time the motor receives a step pulse.
The most popular types of stepper motors are permanent-magnet
(PM) and variable reluctance (VR).

Half Stepping

The motor can also be "half stepped" by inserting an off state
between transitioning phases.This cuts a stepper's full step angle
in half.For example,a 90° stepping motor would move 45 on each
half step,

Typical Stepping Sequence for a Four Phase Stepper Motor

A change in the coil states (ie. changing from state 2 to state 3 as
shown above) results in a single step of the motor shaft. Direction
is easily controlled by running through the above sequence either
forward or backward. It should also be noted that the coils A and A'
are always oppositely charged, as are coils B and B'. By inverting
the signals going to coils A and B, the corresponding signals A' and B'
can be attained. Thus, only two control lines are required to place
the motor into any one of the 4 possible states.


Thursday, January 15, 2009

Stepper Motor Data 1

program shows the basic operation of the stepper motors

This program shows the basic operation of the unipolar and
bipolar stepper motors. In addition there are demos of a translator
, oscillator and indexer.

Basic theory of Stepping Motors

Stepping motors are electromagnetic, rotary, incremental devices
which convert digital pulses into mechanical rotation. The amount
of rotation is directly proportional to the number of pulses and the
speed of rotation is relative to the frequency of those pulses.

Static or holding torque - displacement characteristic
The characteristic of static (holding) torque - displacement is best
explained using an electro-magnet and a single pole rotor . In
the example the electro-magnet represents the motor stator and is
energized with it's north pole facing the rotor

Stepper Motors: Principles of Operation

Permanent Magnet stepper motors incorporate a permanent magnet
rotor, coil windings and magnetically conductive stators. Energizing
a coil winding creates an electromagnetic field with a north and south
pole .

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Monday, January 12, 2009

Microstep Stepper motor driver circuit

Half-step, full-step and microstep Stepper motor driver

The L6219 is a bipolar monolithic integrated
circuits intended to control and drive both winding
of a bipolar stepper motor or bidirectionally control
two DC motors.
The L6219 with a few external components form a
complete control and drive circuit for LS-TTL or
microprocessor controlled stepper motor system.
The power stage is a dual full bridge capable of
sustaining 46V and including four diodes for
current recirculation.

- Able to drive both windings of bipolar stepper
- Output current up to 750 mA each winding
- Wide voltage range: 10 V to 46 V
- Half-step, full-step and microstepping mode
- Built-in protection diodes
- Internal PWM current control
- Low output saturation voltage
- Designed for unstabilized motor supply voltage
- Internal thermal shutdown

L6219 Datasheet pdf

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Saturday, January 10, 2009

bipolar stepper motor with current control

The UDN2916B, UDN2916EB, and UDN2916LB motor drivers are
designed to drive both windings of a bipolar stepper motor or
bidirectionally control two dc motors. Both bridges are capable of
sustaining 45 V and include internal pulse-width modulation (PWM)
control of the output current to 750 mA. The outputs have been
optimized for a low output saturation voltage drop (less than 1.8 V
total source plus sink at 500 mA).

- 750 mA Continuous Output Current
- 45 V Output Sustaining Voltage
- Internal Clamp Diodes
- Internal PWM Current Control
- Low Output Saturation Voltage
- Internal Thermal Shutdown Circuitry
- Similar to Dual PBL3717, UC3770

UDN2916 Datasheet pdf

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Wednesday, January 07, 2009

2A Step Motor Driver Circuit

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

The L297/A/D 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 switchmode
control of the current in the windings.


L297 Datasheet pdf

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Friday, January 02, 2009

PWM Generator with Current Limit Circuit


The SG2524 and SG3524 incorporate all the
functions required in the construction of a
regulating power supply, inverter, or switching
regulator on a single chip. They also can be used
as the control element for high-power-output
applications. The SG2524 and SG3524 were
designed for switching regulators of either polarity,
transformer-coupled dc-to-dc converters, transformerless
voltage doublers, and polarity converter applications
employing fixed-frequency, pulse-width-modulation
techniques. The complementary output allows
either single-ended or push-pull application. Each device
includes an on-chip regulator, error amplifier, programmable
oscillator, pulse-steering flip-flop, two uncommitted
pass transistors, a high-gain comparator, and current-limiting
and shut-down circuitry.

SG3524 Datasheet pdf

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