Adding Schottky Diode to fix the Naze32 V6a 

Adding Schottky Diode to fix the Naze32 V6a reverse current issue… by David HK July 2016

I bought a cheap clone Naze32 V6a from China, which does not have the diode to prevent reverse current from the USB power-in to the BEC power-in (either ESC or PDB).


If I wired the Naze32 5V BEC power-in from an ESC BEC output, whenever I connect the Naze32 to my PC via the USB, I will noticed the motor that is providing the 5V BEC power is twisting, because it is getting the reversed current from the Naze32 (via the 5V power-in red wire).

If I wired the Naze32 5V BEC power-in from a PDB (which is my current setup), whenever I connect the Naze32 USB port to my PC, my PC will complain “USB port drawing too much current… etc” (or similar message), this is because the quite a lot of current from the PC USB port is being drew to the PDB via the Naze32 5V power-in (revised current), as my PDB also connecting the fpv cam+vtx, and 2 LEDs.  Normally this shouldn't happened if the Naze32 has a diode to prevent reverse current getting out via the 5V power-in port.

The above issue only happens in Rev6a of the Naze32 board.

A workaround is to power the Naze32 with a Lipo battery first, and then connect the PC USB, so that the PDB is getting sufficient 5V voltage from the Lipo via PDB 5V out, hence no reversed current will happen.

Recently, I found a permanent fix, from this link:

So I visited my local electronic shop, they don’t have the 1N5819 in the standard wire connector version, but they have the surface mount SS14 version, which is the equivalent of 1N5819.  It is very small, less than 3mm x 5mm, as you can see it on my thumb below.



I cut the 5V power-in red wire and soldered the diode in between.  Note that the connection is directional, there are lines mark (or grey colour mark) at one end of diode, which is the cathode end, this should be the output direction of the current flow (ie connect to the Naze32 5V power-in).  Here is what it looked like of the connection (unfortunately I’ve already shrink-wrapped before taking this photo, but I want to show you how small the diode is).    


So problem fixed! Period!


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