I built two L297 L298 bipolar stepper driver. I used one circuit some days ago (it was working) but today I tried to use it again. Surprising thing is that, it was not working, and after debugging, I found that L297 output lines ABCD were not working. I dont know why L297 is not working.

Then I connected SECOND similar circuit, I used it for some hours. After an hour break. I found, it was also not working in the same way like first circuit.

Any comment?

 

Hello,

Can you post your schematic?

Is it similar to the circuit in the L298 datasheet?


Bertus

 

Yes, it is similar to this as shown in attached image.

Here I keep Enable pin (l297) free. The circuit was working when it was free and when it stopped working then I connect it to +5v to keep it high. But there nothing happens.

Now it is not working. Do I need to reset L297 by making it Low then High again?

 

Hello,

At what voltage is Vref adjusted?
1 Volt will be the maximum value as that will sens a max of 2 Amps @ 0.5 Ohm sens resistors.

Bertus

 

I tried adjusting the volt at Vref but all output lines ABCD keep low.

Both circuits are not working but there is not any burning sign or smock.

 

Hello,

What voltages do you measure at Vref Sens1 and Sens2?
The outputs will be blocked when Sens1 or Sens2 is higher than Vref.

Bertus

 

Recap: Two L297 L298 drivers was working but after a break of some times, they stopped working.

I checked the sense resistor volt with both circuits. The volt at both sense resistor with both circuits is 3.3V.
Then I set Vref volt equal to 3.3 or less with both circuits.
But still output ABCD lines with both circuits keep LOW.

Here I keep Enable pin (l297) free. The circuit was working when it was free and when it stopped working then I connect it to +5v to keep it high. But still it is not working (keep low).
Now it is not working. Do I need to reset L297 by making it Low then High again?

 

Hello,

What is the value of the sens resistors?
When they are 0.5 Ohms as in the schematic, the current would be 6.6 Amps @ 3.3 Volts Vsens.
Then the L298 will be fried as the maximum allowed current is 2 Amps.

Bertus

 

The volt at Vref is 3.3v. I try to reduce it to 1 or less.

I would like to show two bipolar drivers here, there is not anything to adjust.
Plz tell me if there is still something to take care of.

 

In above two bipolar stepper driver circuits, there is not anything to adjust critically. I want to make me free from critical settings.

I want to drive my stepper motor (bigger one = 4kg) at 35-40v.
Please give your expert comments about above two simple drivers.

I think, my two L297 chips in two circuits have burnt out. In above two simple circuits, I think, there is no risk of component burning.

 

I just want to use Mosfets instead of H-bridge chips such as L298, because it offers higher range of amp and volt. you may suggest any change in above circuits.

 

Why not use one of the many available dedicated stepper driver IC's? The L297/298 chips are very inefficient (drops more voltage) compared to a dedicated stepper driver.

 

Hey Shortbus,

You may suggest some.

 

You need to look and see which ones match your needs. There are also stepper driver boards very cheap on Ebay.
http://www.digikey.com/product-sear...t=0&page=1&quantity=0&ptm=0&fid=0&pageSize=25