# Thread: power supply for stepper motor

1. ## power supply for stepper motor

I am using a pair of stepper motors for building a AGV .specification of each stepper is :

1 A/phase
5 V/phase
1.8 degree/phase

It is a unipolar stepper motor with four terminals and 2 other terminals soldered to form the COMMON . .What sort of power supply source should it require?? (I Heard that current supplied by the source is important for driving stepper). For driver circuit we are connecting a ULN2003 and its input is provided by AtMega16L. How should we construct a portable 12V supply for this assembly???

2. 1. ULN 2003 cannot drive that Stepper. Better use a L298. Read the data sheets before doing anything.
2. Just use a 12v battery on-board.

3. Originally Posted by docel
1. ULN 2003 cannot drive that Stepper. Better use a L298. Read the data sheets before doing anything.
2. Just use a 12v battery on-board.
I couldn't understand it..can't ULN drive a unipolar stepper motor, I thought it can't drive bipolar motor

4. ULN Maximum Current - 500mA (600mA peak) per channel
These are rated at 1A per phase.
L298 gives 2A per channel.

5. does any power supply ( of 12V) works with stepper motor if we use ULN 2003 ?? what i mean is ..do we need to see the current rating of the power supply?

6. I couldn't understand it..can't ULN drive a unipolar stepper motor, I thought it can't drive bipolar motor
Did anyone say ULN can drive a bipolar motor??

does any power supply ( of 12V) works with stepper motor if we use ULN 2003 ?? what i mean is ..do we need to see the current rating of the power supply?
Its not about the voltage. Its about the current. Guess you didnt understand Doc's post.

The supply should have a current rating a bit higher than what you require. In you case, supply should be at least 1A, since your motor is rated at 1A @5V

ULN cannot drive your motor because ULN cannot handle currents above 500mA. So you need a driver which can drive at 1A, thats why an L298 was suggested.

7. hi !
i purchased a AstroSyn stepper recently . i have a 12V - 1A power source which i got it made at Visha (7812 regulated supply).
The Stepper motor is taking up too much of current. I have already burned out a ULN2803 driver IC .
Now after reading the posts here i think i will be using L298 .
Could u please provide me with the connection diagrams for a Unipolar stepper and L298 ?

i am using my PC parallel port to control this motor.

Thnx.

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