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I'm looking to make an Arduino powered rock crawler with 4 motors (want independent control of each wheel, also need to reverse).

I'm looking into buying 12V DC motors that seem to have about a 1A current draw. I'm looking at the 20 rpm 12V version here. Not sure if the motor will draw more current than 1 Amp based on the limited data sheet.

My original thought was to use 2 L298N motor drivers. I then realized the large voltage drop would be too inefficient so am now looking into MOSFET based drivers.

I'm now looking into using a set of DRV8871 (datasheet) or TB6621 (datasheet) motor drivers. Each of these appear to be much more efficient MOSFET based drivers. Would the DRV8871 be superior in this scenario?

Which of these drivers, if either would be appropriate for this project? I'm open to using other motor controllers as well.

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  • \$\begingroup\$ The DRV8871 looks decidedly superior. It is one-channel and can be distributed closer to motors, it is more powerful, it has twice of operating voltage (15V is dangerously close to system power 12V, which might have spikes). It is smaller, it is faster (max 200 kHz PWM versus 100 kHz for the Toshiba part). \$\endgroup\$ – Ale..chenski Feb 12 at 4:43
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The question you didn't ask: you can figure out the stall current of those motors. Stall current is roughly \$i_r + (i_r - i_{nl})\frac{\omega_{r}}{\omega_{nl}}\$ where \$i_{nl}\$ is the motor no-load current, \$\omega_{nl}\$ is the motor no-load speed, \$i_r\$ is the motor rated current, and \$\omega_r\$ is the motor rated speed. So I get around 3.5A to 4A stall current.

Of the two parts you list I like the TI part better, and either part is better than the L298. I think it'll work for you. I like it because it has built-in current monitoring, which looks to be programmable, and because the data sheet seems more complete. The part about the data sheet may just be a consequence of me being more used to TI data sheets, however.

You really don't want to run the motor at stall current if you can avoid it -- so setting the driver current limit to 1A or 1.5A would probably be a Good Idea.

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Yes. MOSFET based H-Bridge drivers like these are well suited to your application.

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  • \$\begingroup\$ Which one would be better used for this scenario? \$\endgroup\$ – Claire Jacobs Feb 12 at 1:02
  • \$\begingroup\$ Which one is better is a matter of opinion. It's such differences of opinion that drive the diversity of solutions you'll find on the market. \$\endgroup\$ – TimWescott Feb 12 at 1:30

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