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MX1508 motor driver flyback diode controversy

MX1508 motor driver flyback diode controversy

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Hi I am trying to use the MX1508 motor driver with my 6V dc motor, but I’ve read criticism that it doesn’t have flyback diodes.

I’m seeing conflicting opinions online about this.

For example, in this article:http://docplayer.net/171091206-Using-the-mx1508-brushed-dc-motor-driver-with-an-arduino.html the author explains “There is some discussion on some forums where people describe a few problems with reverse EMF voltage spikes coming back through the system and confusing their micro-controllers. The MX1508 breakout board sold by Banggood appears to have all the necessary capacitors and flyback diode to combat this.”.

Here is an example that I’m sure the author is referring to: How can i stop DC motors from dropping out my arduino?

I’ve also seen the following counter: “I was wondering about the statement: ‘the MX1508 has no fly back/free-wheeling diodes present, though they are advised by the chip manufacturer’. Wouldn’t the MOSFET structure itself act as a fly back diode, similar to other H-bridges like the L9110 and TB6612?”

What is really going on with this MX1508 motor driver? Is it safe to use on its own without any additional diodes?

Thanks all for your time and help with this.

MX1508

motordc-motordrivermotor-controllermotordriverShareEditFollowFlagasked 2 hours agoJason Easton3711 bronze badge

  • 1The Chinese data sheet for the MX1508 shows it uses MOSFETs in the H bridge and those MOSFETs have internal reverse (bulk) diodes. But I wouldn’t use it because (a) I don’t speak Chinese and (b) I have no faith in its quality (now or in the future). What to check for when buying an electronic component or module. – Andy aka 2 hours ago 
  • @Andyaka Thank you for the response. I’ve purchased one before and have it available. Would there be any way to check if the reverse diodes are truly functioning as expected? Should I hook up oscilloscope probe to motor + and oscilloscope ground to motor – and see if my voltage jumps to high values? – Jason Easton 2 hours ago 
  • I wouldn’t trust it so any advice I give is inherently weakened by its lack of believability. – Andy aka 2 hours ago 
  • @Jason Easton, MX1x08 seems to have built in flybacks. See Appendix O of my answer to the following Q&A: Choice of DC motor Drivers – EESE 2020jkul16 electronics.stackexchange.com/questions/510755/…. Cheers. – tlfong01 12 mins ago   Delete

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