The Acro Naze32 Rev 6 and Afro Mini Naze32 flight controllers have no diode/mosfet circuit to prevent power from the USB port being fed back to your input DC-DC converter or speed controller, this can cause issues when you want to calibrate ESC or to program them.
The easiest way to fix this is to put a schottky diode between the two as illustrated in this schematic:
The VIN would come from your 5V regulator/DC-DC and the LOAD is your NAZE32 rev6
Any 20V 1A diode like 1N5819 1N5817 will work. Here are the Schottky Diodes 20V 1A 1N5817 from Amazon.
12 thoughts on “Naze V6 Reverse Voltage Feedback Issue – Schottky Diode Fix”
Thank you for the pictures (a thousand words)… In theory you could put a diode on each of the Red wires coming from the ESC servo lead… wouldn’t that work the same… Solder and shrink tubing… Just trying to avoid soldering the modification to the board… Is there any advantage of having all the ESC’s powering the board… Electronics not my strong point, but soldering not a problem…
You shouldn’t actually connect all the red wires from each ESC, if you are using the ESC to power your flight controller with 5V you only want one of the ESC red wire connected(cut the other 3), and that red wire should go through the diode.
You can put it in the wire leading to the board and not on the board itself, I just put it on the board as it seemed simpler, and I solder all wires directly without connectors.
If you are using a separate BEC(battery eliminator circuit, really just a 5v regulator) or PDB(power distribution board) to create the 5V from the battery then you dont want any of the red wires from ESC connected, just cut them off.
The reason is that the ESCs power themselves with their own regulators, and you dont want to connect 5V regulators together as they will all sort of fight each other.
Even with none of the red wires from ESCs connected to the flight controller it is still possible to have them turn on from USB because without the diode the 5V can go back through your 5v regulator and supply 5v on the main flight battery power lines, so then the ESCs are being powered from their main battery input wires and turn on.
Hope that explains it all 🙂 let me know if you have other questions.
Thank you for your help I was starting to pull my hair out.
Hi, thanks for the mod. Its partially workout. you can now connect usb without disconnecting your pdb but still cant connect battery + usb. Im using afroflight rev6
Really? What happens if you connect the battery and USB? The diode should let whichever source is higher in voltage power the flight controller board.
Oh and make sure you have cut the red power wires from your speed controllers if they are not opto types.
My esc’s are opto’s, Well perhaps I found the problem, my osd is connected to the Rx, TX path and that might conflict with the USB while battery is connected, what do you think? I still have to check that
Yes depending on which flight controller you have that could be the case. Some of them use the same RX and TX lines for both. The newer F3 and F4 have enough serial ports that this usually is not an issue.
I have AfroFlight32 rev6 first batch I guess, rev6a n b that came after have this issue solved
I believe all the afroflights/naze32 use the F103 processor which uses the same serial port for the USB port and other things depending how it’s configured. When I was using that controller I used a connector on the TX and RX to the OSD so I could disconnect it whenever I wanted to use the USB port.
i ran into this problem. i webed it for 3 hours..and finally ran into your answer. i dont have becs.but the wire that feds the fc, i cut and wala, it works..usb pluged in..motor master up, plug in bat. and beepity beep beep and was easy as it should be..although ill have to put a diode in..i be sure to stay away from these defective FC. pain in the ass.
cut because i solder all my wires into the fc too..