VNH driver operates in 24V

Dear all,
I got a problem for the VNH3SP30 motor driver. It was very easy to short when it is working in 24volts and the IC itself gets very hot( and then out of function). The PWM signal is 3.9KHz and the max output current is less than 8A…

Can VHN3SP30 working good in 24 volts? I know it is good to use in the 12 Volts, but the spec says that it can be used at Vcc (max) = 40 volts,30A output.

by the way, I purchased the “Pololu Motor Driver MD01B” to do the test. It is a pain to get burned.



The absolute maximum rating for the VNH3SP30 is 40V (meaning you can supply 40V without destroying the IC), but the maximum operating voltage is listed as 36V in the datasheet. However, as we have written on the product page, our experience is that shoot-through currents make PWM operation impractical above 16V. If you need to exceed this voltage, I recommend you avoid PWM operation or at least try the lowest frequency PWM that is practical for your application, though the best solution would probably be to go with something like our high-power motor driver 36v9.

- Ben

Hello there,
What is your recommand frequency if we use it and operates in 24 volts.

My recommendation is to not use PWM control beyond 16 V. Since the issue is the result of shoot-through, you are getting large current spikes every time the PWM signal changes state during the brief period where both the high and low MOSFETs are partially on. Decreasing the PWM frequency will decrease the frequency of these current spikes, but they will still be there. You might be able to use the driver at higher voltages, but I don’t really have any specific numbers for you; you’d have to test it out for yourself with lower PWM frequencies.

- Ben

Ok , might chang to the drive, “high-power motor driver 36v9” you recommended.
I have another motor operated at 42V, 6A. Can this high power motor driver 36v9A afford this voltage. The Spec Maximum operating voltage is 50V.


If 42V is your nominal battery voltage, that’s definitely too high for our drivers since the actual voltage could easily be over 50V. If 42V is somehow derived in a way that you are sure 50V won’t get exceeded, the motor driver could work.

- Jan

Hello There,
I got a "Pololu High-Power Motor Driver 36v9 " whcih you suggest me to use for 24V motors.

I encountered the FF1 stay Low and FF2 stay High. This status happened when I changing the DIR pin manually by switching DIR pin from +5 to Gnd on the break board( operate at motor 24V). The upper-left N-Mosfet ( the G, D, S are all short when tested, OUTA is on the left side ) was somehow breakdown.

please advice.

If it was working for a while and then failed, there’s probably not much you can do about it. You can email us to get an RMA number so you can send it back to us.

- Jan


What is the stall current of your motor at 24V? Was your motor spinning at full speed when you changed the DIR input from high to low?

- Ben

Dear Ben & Jan,
Thank you for all your reply.

The stall current is around 40A. Yes, I did chang the DIR when it run at full speed.

Last night I had tried another moter driver to give PWM and DIR from MUC to replace break board experience. I also put the DIR and PWM signal on the oscilloscope to see the signal. It was running great for around 5 minutes. But somehow the motor stop running and power supplier had a current around 0.48A( I only run at 12V). The heat came out from the 24 pins IC. The motor dirve then breakdwon again but this time it’s the 24 pins IC. It was so frustrating.
We did switch one good N-Mosfet to the board which was first breakdowm. So, one of the driver is survive and one is dead now.
Please advice how to slove this problem.

Thank you.

Is that a 40A stall at 24V? I interpreted your initial post to mean that your motor had a “max output current of less than 8A”. If it has a 40A stall, 8A is definitely NOT the maximum output current. Did you mean that the free-run current of your motor is around 8A at 24V? When you switched from full speed forward to full speed reverse, you were probably putting close to 80A through the controller, which well exceeds its specifications.

It sounds like you overheated the second driver. These high-power motor drivers do not have thermal protection, so you need to pay attention to the current you are trying to pull from them. What was the current draw during the five minutes it was running well? What were you doing to the motor during that five minutes (e.g. were you toggling the direction input while driving the motor at full speed)?

- Ben