What is a stepper motor driver?
Stepping Motor driver is an electronic device used to drive stepping motor.
It usually does not perform any operations on its own and must be used with controllers such as the sharp r60.
There are many different types of stepper motor drivers, but in general, they all do the same thing-Move the stepping motor.
Why do you need a stepping driver? The stepping motor needs voltage and/or current that the controller cannot generate at all.
Therefore, we need to use a stepper motor driver.
The electronic device will convert our motion instructions from the controller into a sequence in which the winding of the stepping motor will be turned on or off while still providing sufficient power.
All of this can of course be generated by microcontrollers that drive several FETs, but design and programming take time. Fortunately, there is already a solution.
Driver types, usually, have two types of drivers. Constant voltage driver (Left/Right Drive)And a constant current driver (Chopper driver). Constant voltage driver (Left/Right Drive)
: They are cheaper than constant current drivers, generate torque with voltage, are usually inefficient, and have worse performance than chopper drivers. Constant current drivers (Chopper driver)
: More expensive and more complex circuits, using constant current to generate torque, better performance than left/right drivers, due to many available ICs, and providing better performance, therefore, constant current drivers are almost always used.
You will find integrated circuits that already have integrated FET, which are usually used for lower currents (Maximum is A)
Because they are small and heat dissipation may become a problem.
The other type uses an external FET, and the maximum current is limited only by the external FET used. Micro stepping, stepping motor usually takes 1. 8 °Step motion, that is, 200 steps per turn.
When we need little tricks, this may be a problem.
One option is to use a certain transmission method, but there is another method-Micro step.
Micro-stepping means that we can have more than 200 steps per revolution, and the movement is smaller. This option is already integrated in most ICs.
When the stepper motor is driven in full step, the output of the stepper motor driver looks like a square signal and produces rough motion.
The larger the micro-step distance, the more the output signal looks like a sine wave, and the smoother the movement of the stepping motor. But this has one drawback.
With the increase of the micro-step value, the torque will decrease a lot. If the value is too large, the motor may not be able to generate enough torque or even rotate.
Generally, 1/4, 1/8 or even 1/16 can produce satisfactory smooth motion while still producing sufficient torque.
The following figure shows how the output changes when different microstep values are selected.
You can see that the output looks more and more like a sine wave. So what do these values really mean?
Micro steps tell us how many micro steps a stepper should take to produce a complete step.
The value of 1/1 tells us that the stepper must take a micro step to produce a complete step (So there is no micro step).
The value of 1/2 is called half step, which tells us that the stepping motor must take 2 micro steps as a complete step.
This means that the stepper motor should turn a full circle 400 steps.
The value of 1/8 will tell us that the motor takes 8 micro steps per whole step and 1600 steps per whole turn. The same principle applies to all microstep values.
How to drive stepper motor driver most stepper motor drivers have a step/direction input.
This means that each driver requires only two signals.
Stepping signals are used for stepping and look like PWM signals. Each pulse means that the stepper will move one step (Or micro step).
The dir signal represents the direction and is used to signal the direction of the step rotation (CW or CCW).
In conclusion, we found that if our design requires the use of a stepper motor, the stepper motor driver must be used because the controller cannot generate sufficient current and sufficient high voltage.
There are different types, but chopper drivers provide the best performance.
Moreover, micro-stepping provides a good solution at first glance, but it causes the problem of torque reduction. It is still very useful, but must be used correctly.
There are many different ICs that can be used to drive stepper motors, and many already manufactured solutions (For example, ruite R42 and R60)
Plug and Play solutions are available and easy to use.
TAG stepper motor driver