MOSFET for stepper motor

Thread Starter

Adamko

Joined Oct 30, 2012
2
Hello!

I have a problem i do not know which transistors to use for my application.
I have unipolar stepper motor:
4 coils (9 wires, two wires pro coil and one ground)
R = 5Ω (pro coil)
Imax.= 1 A (pro coil)
switching frequency < 50kHz
power supply = 5 V,

I try to realize a circuit with transistors TIP122, but they were to slow. Motor was working only at low frequency till 2 KHz pro step (picture up). I think i need to use MOSFET-transistors. The problem is that i do not know which one to use. Does anyone has experience with similar things? I do not know too how to design a circuit. Can i connect gate directly to the microcontroller, Source to power supply ( 5V power supply from an old computer source) and Drain to ground or do i have to add some safety diodes and resistors?

I would appreciate every kind of help!
Thanks!

Adam
 

Thread Starter

Adamko

Joined Oct 30, 2012
2
One question more: Direction of diodes on source of transistors? I thing that in example U posted no current will flow through transistor,or? Why U put diodes there anyway?
Thanks for your help!
 
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