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• weird update, all of a sudden, my controller board stopped blinking its led (meaning something was wrong) and started becoming extremely hot when plugged into my laptop. I probed across 3V3 and gnd and see that now its shorted on the controller board. something must have happend during my testing to somehow short 3V3 to gnd with my controller attached, thus damaging the CB and most likely the MCU. In addition, for some reason the LTC seems to not work properly because it is able to turn on the output without a 3V3 reference, which should not happen. After waiting a couple of minutes and trying again, it seems that this is not the case, and the bulk capacitor was probably the reason I was still seeing output on the LTC as it was holding the 12V for a bit longer.

• More testing on switchover (with a new controller board that I haven't destroyed of course), I will check if the supply will switchover in the cases outlined in josh’s test plan → that is if the primary source goes OV or UV, the ltc will switch to the other supply. the following table are my results

• from the above table, the values for UV seem a bit off, otherwise though it was successful.

• adding on to the switchover times recorded, another important one josh noted is the time from swithching from aux to DCDC, and the time in which there is no 12V reference on the output. Looking at the scope shot below, there is not really a moment where the 12V output is stopped, which means that the caps are large enough to keep it going through the switchover time (purple is output voltage, blue is aux voltage and yellow is DCDC voltage with the rise being when i turned DCDC on and it took priority over aux)

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• Note, that all the tests done today were done with a 1A load. DCDC would only ever supply 17A max, and even with out power budget we dont expect to fly higher than about half that. To confirm the board is able to handle high loads, I will be running the aux supply at 10A for about 10min to see if there is any weird heating or other faults. Note: I have placed a 20A fuse on the aux input so it should be sufficient for this testing. Also note that the voltage form the supply is 13.5V. Also note that while doing this, I found that loading 10A has the output voltage at 12.7V! Thats a huge drop from 13.5V, 800mV to be exact. I probed the voltage difference from the input annode to output annode, and only notices 350mV drop, so the rest ~450mV has to come from the wires I’m using (18 and 16 AWG).

• After about 10min, i used a temp probe to measure some components facing that high current. The following table summarizes that:

• It seems that there are no huge temp or voltage drop problems board side, so it seems good!