Description
Summary
Okay this is a big dummy move on my part! Didn't read the data sheet carefully enough and just realized that the AP2265X load switches are only rated to work up to a recommended 5.5V and a maximum 6V.
This is not an issue for the face load switches (since we are just supply 3.3V through them) but it is potentially a big problem for the burn wire and heater circuits that can be supplied with up to 8.4V if a 100% full battery pack is connected. At this time we have not seen a failure of either circuit due to this, but most people have also not need powering their V5 boards from battery packs. It is unknown how long it would take for a failure to manifest itself, but it is likely that this can become a mission ending point of failure if the load switches burn through (get stuck in the closed - passing current - configuration due to gate breakdown).
Location of the Problems
Plan for Resolution
We'll try to do a few things to resolve this issue:
- Warn all existing users of V5a flight controller to boards that they should limit or completely stop the use of battery packs mitigate the chance of load switch failure
- Replace the AP2265 load switches in the burn wire and heater circuits in the next board revision (unclear if that will be V5b or a full V6 jump at this point)