Small form factor driver board with integrated encoder

Hello all! I have designed this board for size critical projects. It features a DRV8711 BLDC driver from Texas Instruments and AS5600 magnetic encoder.

Here is general information:

-28.5mm x 30mm footprint
-Operating voltage: 5-12V
-Continious current: 2A(limited by connectors)
-Current sense feedback(0.5V/A)
-AS5600 12 bit magnetic encoder

Hoping that it will work smoothly with simplefoc! Will update this thread once I have got the boards produced.

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I can see some problems in your schematic:

You have used a 10V capacitor for the input voltage (C1, C4, C7), when you state the operating voltage will be 5-24V. You need to pick a capacitor rated for at least your operating voltage, otherwise the capacitor might fail (possibly explode). There is also another 6.3V capacitor (C3) which you need to replace for the same reason. I also suggest limiting the maximum operating voltage to 20V, as the absolute maximum rating of the chips should not be interpreted as continuous ratings.

You can’t connect VIN to the 5V pin of U2 (AS5600) unless you only intend to run the board on 5V. You should add a buck regulator or LDO to generate a 5V rail.

You say that the gain setting is 0.5V/A, but you have tied the GAIN pin to AVDD, which means the gain is actually set to 2V/A. You need to connect it to GND via a 47k resistor to get 0.5V/A gain.

You can get rid of R2 if you want the nFAULT pin to light a LED. In your current schematic R2 does nothing.

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I would replace this encoder with a fast one. 5600 is for servos.

Also it would be best if you post a picture or pdf of the schematics and pcb layouts. I don’t have kikad. Also downloading gerbers and looking at them is very time taking. You can get a lot more help if you make it easy for people to instantly see your design.

Cheers,
Valentine

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I was about to comment the same, it would be nice if .pdf is provided for schematic and layout, even though I use Kicad, I don’t want to have to setup whole project just to look over :slight_smile:

You can get MT6701 encoder, higher resolution, smaller, lower noise, and cheaper than AS5600. Or there are many others to pick, too.

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@alperbasarn

As much as I passionately hate reddit and wish it sinks to the bottom of the whatever hell is on earth, they do have some good advice about PCB reviews that you must follow to get the best help here.

https://old.reddit.com/r/PrintedCircuitBoard/wiki/index

Cheers,
Valentine

hey guys thanks for feedback! in the github link of original post, you can find .pdf files for both schematic and layout!

  1. You need to provide also values on the PDF for the resistors, instead of saying R1, R2, etc.
  2. Your capacitors are not sized for the voltage expected.
  3. The fuse is 2A but your mode is 5A.
  4. VIN is connected to 3.3v out (???)

I’m sure there is more but I’ll stop here until you fix those.

Please review all components one by one and assure they are sized for the purpose.

Change the heading of the thread to something like “Review requested, etc…”

Follow the guidelines I linked.

Cheers,
Valentine

thank you very much for your precious time and review. I will process your comments and come back asap!

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Please take your time. This is a learning experience. We are happy to help you learn. Making hardware is hard, that’s why it’s called hardware

Cheers,
Valentine

2 Likes