stepper motor question

[armess]

motor stepper 5a

I have a stepper motor driver in which i am using TIP122 to drive a 1Amp 2 phase unipolar stepper motor.
Due to the less torque provided by the motor i need to change it to another one. The new motor is asking for 2Amp per phase. What modification do i need to do in my circuit?
Can somebody plz help me on this.

Added after 3 minutes:

I am not using a microcontroller in the circuit.

 

[A.Anand Srinivasan]

stepper motor+driver+tip122

use some other power transistor... i've seen power transistors with a current range of 4A... go to some semiconductor devices company site and search for power transistor... you'll find many....

 

[roykyn]

no modification is required according to the details given by you.....tip 122 can handle up to 5amps according to this doc.but i have seen most of them get heated at current beyond 1A.A heat sink will help and also increase the life of the tip 122.if it get heated
a lot then you can try two tips in parallel.But i cannot assure it might work.just check if equal amount of current if flowing through of of the TIPs.
https://www.learn-c.com/tip120.pdf

 

[armess]

Why get into using a heat sink??
Why not use something which can handle 2 Amps without getting heated....
Plz suggest one.................

 

[A.Anand Srinivasan]

2A is a huge current for any device... consider a voltage of 5V across the device and this leads to a power dissipation of 10W.... mostly these devices would have a metal cap which by itself would act as a heat sink... so use heat sink just incase the heating is too much....

 

[armess]

That means i need to only increase the currentgiven by my power supply by using a transformer with higher current rating and the cct should work?????

 

[A.Anand Srinivasan]

i referred a little and found there are MOSFETs which could handle the current you are requiring... but they surely would get heated.... you better go to some company sites and see for power MOSFETs...

 

[armess]

TIP122 has a current rating of 5 Amps.
Will they not work as it is?

 

[PaulHolland]

Better use a MOSFET look at IRF or Vishay and select a mosfet with < 50mOhm Rds_on in TO-220 so you do not need heatsinks.

Paul.

 

[A.Anand Srinivasan]

ya.... TIP122 with a current rating of 5A would be just fine because due to that high a rating the heat sinking given by the metal cap in them would aid you...

 

[armess]

How can i check how much current rating motor the circuit will be able to drive?

 

[A.Anand Srinivasan]

it depends the on the output drive of the circuit you are using and the amount of amplification that you use at the output.....

 

[mghoffman78]

The TIP122 can only handle 5A with good heatsinking. Lets say best case when you turn the transistor on you get a VCE of 0.75V. At 2 amps this results in a power dissipation of 1.5W. If you use the TIP122 with the TO-220 package without heatsinking, the junction to ambient thermal resistance is say 63 degrees Celsius per watt. At 25 degrees celsius that results in a junction temperature of 119.5 degrees Celsius. While that is not hot enough to destroy the device it sure will burn the crap out of your finger if you touch it.

You can do this calculation in reverse to determine the max power dissipation of the device to keep it at or below a certain temperature.

Mike