Stepper motor "driver"

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Hi all,

Bit of an odd one.
I have an aftermarket car ecu that has a 4 wire stepper motor attached to it.
Unfortunately, the ecu is current limiting to 1 amp.

The motor needs 1.85 amps (6.5 ohm motor, 12volts).

It therefore needs a bigger current supply (no position feedback needed as the throttle body and ecu already have that side covered).

It has been suggested that mosfets or BJT transistors be used.

Not sure what components and configuration is needed.

thanks

Rod

2

Hi Rod,

I think you’ll need to setup your own motor driver circuit specifically for this application. Here’s a really good video guide that should get you well along the way!

Let us know how you go, and if you have any questions we’re here to help!

Regards,
Oliver
Support | Core Electronics

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Hi Oliver,

Thank you very much.

cheers

Rod

6

Hi Oliver,

Looks like this would be the go…

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Hi Rodney,

It should be able to handle that load although it’s pretty close to the limit, as the L298N is rated for 2A and up to 35V driving, with a max of 25W continuos (2 A * 12 V = 24 W). That’s a simple H-Bridge which essentially allows you to control two high current, high voltage (relatively) pairs of outputs in either direction from much lower-powered inputs. You can find the specifications and the part available from our website at the link below. Please note that this is not a stepper motor driver, and only essentially “upgrades” four GPIO of the Arduino (if you’re using a different controller with a higher voltage output be sure to include a resistor respectively) to control higher powered loads.

If there’s anything else that we can do for you please let us know.

Bryce
Core Electronics | Support

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Hi Rodney and Bryce,

Easy point to miss, but that won’t work for you directly! I expect your ECU will output somewhere between 12V and 14V. The L298N has a control voltage limit of 5V-7V.

I’d suggest using a simple resistor voltage divider between the ECU’s stepper outputs and ground to drop the voltage down to the required 5v.

Regards,
Oliver
Support | Core Electronics

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