Sensorless BLDC motor schematic (update march-21-2013)

Hi All. Here is the first second schematic of a new project. A Brushless DC motor shield.

It use a Allegro A4960 IC controller and a IPD090N03LF n-channel mosfet of Infineon (30V-30A).

We accept contributions or comments.


Jaume Nogues
Vall Hebron Tech School

brushlessShield_march21-2013.pdf (296 KB)

I think it looks good. A few small remarks: - The type of mosfet is not in the schematic. - I can't find what a good value for Creg (C4) is, the datasheet tells "sufficiently large", so I have no idea. - Creg (C4) doesn't have a voltage specificiation in the schematic. It it used to make a higher voltage, so that would be something to know. - If D7 is floating (not HIGH or LOW), the 10k pull-down for the reset could be a high value in a noisy environment. Perhaps 4k7 is better.

Hi Erdin. Thanks!, I will change this items and re-upload it!

Now is update the second version. Soon we start the design of the PCB.

Thanks Erdin!

I think it should work. Making a good PCB for high currents is far more complicated than the schematic.

Is the chip rated to work with Vdd (5V) present but Vbb absent? If not you've got an issue - it would be better to derive Vdd from Vbb on board with a regulator and make the incoming signals opto-isolated or at least add series limiting resistors.

You really don't want it to try powering the motor from the 5V supply via internal protection diodes!

Hi MarkT, reading the data sheet I think there is no problem with this two voltages. When I check the first prototype I see it! Fried Arduino!

What are those resistors for ?

Which, the gate resistors (limits fast switching rise/fall times for reduced EMI), or the current shunt resistors?

The 2W resistors are for sensing motor current.


When will you shield be available for the market?

hi jnogues, thanks for your great work on the A4960 bldc driver, how did you deal with the exposed pad, shoul we tie it to GND or just make it float(not connected), this just made me confused. Thanks for your reply :)


I have just come across this post. I am looking at making a stackable brushless motor shield and would like to build on the work you have already done.

I would like to know the status of this project and if I could get copies of the libraries or .ino files that you used.

Regards Anton Wigley