Stepper Mootr Driver

Go To Last Post
21 posts / 0 new
Author
Message
#1
  • 1
  • 2
  • 3
  • 4
  • 5
Total votes: 0

hi
i want to build a Stepper Motor Driver that can carry at each phase around 5A
so i decide to use mosfet 

i decide to use atmega8 and pic above is driver part

i have 4 diode as protection 

my mosfet has low Rds ON and it capable of 5 A

what i should consider in choosing mosfet and all the component?

what u suggest me on this project?(any pull up resistor or pull down ? any isolation? any transistor to drive mosfet?p chanel or n chanel? what ever come in mind to consider in this project please tell me)

Last Edited: Mon. Oct 30, 2017 - 11:02 AM
  • 1
  • 2
  • 3
  • 4
  • 5
Total votes: 0

This is a simple driver circuit, but you won't get good performance out of the motor. There are many ICs that do microstepping and current control of the motor and achieve much better performance.

 

As for component selections, you will need logic level mosfets since you are driving direct from the AVR port pins. A common mosfet like a IRF540 is not logic level - it needs around 10V on the gate to turn on. 

You will need pull down resistors on the mosfet gates. 10k should be adequate. You need these as the port pins will not be driven whilst the AVR is in reset.

You will need to consider the power dissipation of the mosfets and ensure the temperature rise is not too much and/or add heatsinking. This will determine the package of the mosfet.

  • 1
  • 2
  • 3
  • 4
  • 5
Total votes: 0

I assume you are using the impedance of the motor windings to limit the current?

'This forum helps those who help themselves.'

 

pragmatic  adjective dealing with things sensibly and realistically in a way that is based on practical rather than theoretical consideration.

  • 1
  • 2
  • 3
  • 4
  • 5
Total votes: 0

navidrct wrote:
what u suggest me on this project? ... what ever come in mind to consider in this project please tell me)

What do I suggest? What springs immediately to mind is exactly what Kartman said:

Kartman wrote:
There are many ICs that do microstepping and current control of the motor and achieve much better performance
 

So why don't you just use one of those ICs ??

  • 1
  • 2
  • 3
  • 4
  • 5
Total votes: 0

The "F300" in the diagram is a bit of a giveaway - you've just taken it off the Silicon Labs site, haven't you?

 

https://www.silabs.com/products/mcu/motor-control

  • 1
  • 2
  • 3
  • 4
  • 5
Total votes: 0

Kartman wrote:

This is a simple driver circuit, but you won't get good performance out of the motor. There are many ICs that do microstepping and current control of the motor and achieve much better performance.

 

As for component selections, you will need logic level mosfets since you are driving direct from the AVR port pins. A common mosfet like a IRF540 is not logic level - it needs around 10V on the gate to turn on. 

You will need pull down resistors on the mosfet gates. 10k should be adequate. You need these as the port pins will not be driven whilst the AVR is in reset.

You will need to consider the power dissipation of the mosfets and ensure the temperature rise is not too much and/or add heatsinking. This will determine the package of the mosfet.

thanks allot

 

There are many ICs that do microstepping and current control of the motor and achieve much better performance.

in my country there is not allot IC that can do that unfortunatly

 

you will need logic level mosfets since you are driving direct from the AVR port pins.

can i use transistor to pulled it high to 12 V that its in Drain of mosfet to turn it on?

i want to use Si4410DY as mosfet

thanks allot 

 

  • 1
  • 2
  • 3
  • 4
  • 5
Total votes: 0

Brian Fairchild wrote:

I assume you are using the impedance of the motor windings to limit the current?

I measure the impedance of my motor and its 3 ohms in each phase can I put this value in V=RI to measure the current that it takes?

if the motor has 3ohm phase impedance, if I put 24 volts on it it will take 8 A, is that right? won't it break motor?is it too much for the motor?

im not perfection in motor so thanks for understanding and answering my q

  • 1
  • 2
  • 3
  • 4
  • 5
Total votes: 0

awneil wrote:

The "F300" in the diagram is a bit of a giveaway - you've just taken it off the Silicon Labs site, haven't you?

 

https://www.silabs.com/products/mcu/motor-control

to be clear i search it at google . cheeky

i think this kind of post will answer the basic question of everything.

Last Edited: Mon. Oct 30, 2017 - 11:50 AM
  • 1
  • 2
  • 3
  • 4
  • 5
Total votes: 0

navidrct wrote:
in my country there is not allot IC that can do that unfortunatly

And you can not do international orders?

What country?

"He used to carry his guitar in a gunny sack, or sit beneath the tree by the railroad track. Oh the engineers would see him sitting in the shade, Strumming with the rhythm that the drivers made. People passing by, they would stop and say, "Oh, my, what that little country boy could play!" [Chuck Berry]

 

"Some questions have no answers."[C Baird] "There comes a point where the spoon-feeding has to stop and the independent thinking has to start." [C Lawson] "There are always ways to disagree, without being disagreeable."[E Weddington] "Words represent concepts. Use the wrong words, communicate the wrong concept." [J Morin] "Persistence only goes so far if you set yourself up for failure." [Kartman]

  • 1
  • 2
  • 3
  • 4
  • 5
Total votes: 0

JohanEkdahl wrote:

navidrct wrote:
in my country there is not allot IC that can do that unfortunatly

And you can not do international orders?

What country?


I'm afraid I can't.I'm from Iran

  • 1
  • 2
  • 3
  • 4
  • 5
Total votes: 0

It will be cost effective as well
Can I put resistor to limite current?
Or I can use another mosfet with opamp to adjust current right?

Last Edited: Mon. Oct 30, 2017 - 12:36 PM
  • 1
  • 2
  • 3
  • 4
  • 5
Total votes: 0

Oh dear.  Yes, you will have trouble with international orders.

 

And no, you can't use a pullup to 12V, that will blow (wreck, kill, do bad things to) the pins on your microcontroller.

 

You will need a resistor to limit the current somewhere, but three ohms in your motor will probably do fine.

 

In your schematics the tops of your diodes are not connected to the power rail.  They should be.

 

There's more wrong, but welcome to the world,

 

S.

 

Edited to add:  And PS it's resistance at DC, it ain't impedance until some given frequency that wasn't given!   S

 

No need to be offensive. Moderator

 

Last Edited: Tue. Oct 31, 2017 - 12:50 PM
  • 1
  • 2
  • 3
  • 4
  • 5
Total votes: 0

Scroungre wrote:

Oh dear.  Yes, you will have trouble with international orders.

 

And no, you can't use a pullup to 12V, that will blow (wreck, kill, do bad things to) the pins on your microcontroller.

 

You will need a resistor to limit the current somewhere, but three ohms in your motor will probably do fine.

 

In your schematics the tops of your diodes are not connected to the power rail.  They should be.

 

There's more wrong, but welcome to the world,

 

S.

 

Edited to add:  And PS, you muttonheads, it's resistance at DC, it ain't impedance until some given frequency that wasn't given!  So there.  S


If we have transistor to drive mosfet it won't blow or or do anything to mcu pin.

  • 1
  • 2
  • 3
  • 4
  • 5
Total votes: 0

True, but now you need two transistors, kinda like a half-bridge, one Q (transistor) to drive high, the other Q  to drive low.  This can be done, of course, it's just a bit trickier.  And it'll be an interesting question how long your MOSFET hangs around in the linear region when you turn it off.  Efficient it might not be.  Probably work, though, if you don't mind your MOSFETs getting stinking hot.  Keep in mind the gate capacitance.

 

S.

 

PS - I know you swiped it from a spec sheet, but the idea that all the flyback diodes just go to a Zener really bugs me.  It might work...  Sorta.  It might go bang, too, and in a bad way.  I'd never build a circuit that way.  Hook your flybacks to the rail.  S;

  • 1
  • 2
  • 3
  • 4
  • 5
Total votes: 0

Scroungre wrote:

True, but now you need two transistors, kinda like a half-bridge, one Q (transistor) to drive high, the other Q  to drive low.  This can be done, of course, it's just a bit trickier.  And it'll be an interesting question how long your MOSFET hangs around in the linear region when you turn it off.  Efficient it might not be.  Probably work, though, if you don't mind your MOSFETs getting stinking hot.  Keep in mind the gate capacitance.

 

S.

 

PS - I know you swiped it from a spec sheet, but the idea that all the flyback diodes just go to a Zener really bugs me.  It might work...  Sorta.  It might go bang, too, and in a bad way.  I'd never build a circuit that way.  Hook your flybacks to the rail.  S;

so instead of 4 n channel we need 6 n channel or 5 to drive high end of it in this pic right?

its just a pic that am refering to . of curse i will connect to to the rail

 

 

 

  • 1
  • 2
  • 3
  • 4
  • 5
Total votes: 0

in this pic it show block diagram of st powerstep

it use 8 mosfet and buffer to drive them . so i can use 8 mosfet to avoid any miss clocking 

and i should use buffer something like npn or pnp

please if u have any comment on this pic tell me

  • 1
  • 2
  • 3
  • 4
  • 5
Total votes: 0

What is the part number?

My guess is you don't need external mosfets as they're built in - otherwise why would it need current sensing?

Miss clocking is usually not a problem - missing steps is.

Why do you want us to comment? You haven't asked us a question.

Please don't post random pictures and expect to get anything useful.

 

Let's take a step back and discuss what you want to achieve - do you have a motor in mind that you can purchase locally?

  • 1
  • 2
  • 3
  • 4
  • 5
Total votes: 0

Kartman wrote:

What is the part number?

My guess is you don't need external MOSFETs as they're built in - otherwise, why would it need current sensing?

Miss clocking is usually not a problem - missing steps is.

Why do you want us to comment? You haven't asked us a question.

Please don't post random pictures and expect to get anything useful.

 

Let's take a step back and discuss what you want to achieve - do you have a motor in mind that you can purchase locally?

its POWERSTEP01

im trying to build a circuit for step motor driver 

I need external mosfet cause I don't have any IC to drive step motor. I want to build it myself

miss step is in MCU section of my program let me be worried about it later

I want u to comment on it to tell me if u get any important point to it that I should consider

I post this picture to analyze it to understand it better

one q. why all of u trying to bully me?im new be ok?if u care to help please help. if u don't, just don't do something that I disappointed in this project

 

  • 1
  • 2
  • 3
  • 4
  • 5
Total votes: 0

I’ve tried to provide constructive criticism - at no point have i been abusive or condescending, so please think carefully before writing rubbish.. if you want help, then it is in your interest to be clear.

  • 1
  • 2
  • 3
  • 4
  • 5
Total votes: 0

Kartman wrote:
I’ve tried to provide constructive criticism - at no point have i been abusive or condescending, so please think carefully before writing rubbish.. if you want help, then it is in your interest to be clear.

thanks for all ur help

  • 1
  • 2
  • 3
  • 4
  • 5
Total votes: 0

In your schematics the tops of your diodes are not connected to the power rail.  They should be.

  but the idea that all the flyback diodes just go to a Zener really bugs me.  It might work...  Sorta.  It might go bang, too, and in a bad way.  I'd never build a circuit that way.  Hook your flybacks to the rail.  S

@ Scroungre: before posting, you may want to take a closer look at how the motor is wired.

 

When you see strange things and not sure about, another way to think of it is: would have not been cheaper to just connect the diodes to the rail instead adding a new component into play? Why the designer chose this way ?

Last Edited: Wed. Nov 1, 2017 - 06:49 PM