I am coming into a design that uses a custom designed, 24V brush-less DC motor controller. I am wondering, is it better to power this type of system with a linear power supply, a switch mode power supply (SMPS), or does it not matter?

For the SMPS, I am concerned that the high frequency pulsing nature of the current drain of the motor controller may interfere with its operation.

Thank you.


2 Answers 2


What really matters in this power supply us the ability to sink current, if the servo regenerates energy, which happens quite often. In fact best is a transformer + rectifier which a huge capacitor.

But on the other hand, in my practice most people ignore that and usually no damage is done. I would say that 99% of cases use smps, as they are cheap, small and available, and it works perfectly. Just need to be sure your servo rated voltage is significantly higher than the smps output, so if the voltage risea due to regeneration, no damage is done.


enter image description here Source: http://powersupply.blogs.keysight.com/2011/

A fast responding supply is probably the best thing, since the load is switching and causing ripple. The supply that reduced ripple and returns to the voltage setpoint (and is a 'technically' a lower impedance source) will probably be best. So either a linear supply, or a high performance SMPS.

If your worried about your controller, if the power input is separate from the motor power input, it may be best to run them both in parallel back to the power supply so a power dip won't affect the controller.


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