kehribar
commented
9 years ago Since we are using software based USB library, we can't sleep between measurements, otherwise the device will get disconnected from the bus. Also, we are using the internal PLL peripheral to multiply the internal clock and keep that as constant, and it also possibly draws some fair amount of current. That also necessary for the USB library.
In short, we can't do anything inside the firmware to reduce the heat generated by the microcontroller.
Thermal goo seems like the only option. Maybe after the prototype PCBs arrive we can do by-hand test and see the results. If the results good, we can apply this to the production routine.
The processors get fairly warm. Can we sleep between readings or do something else to minimize the power draw. It seems to be increasing the junction temperature readings.
The ideal situation is for the junction to be accurate to the room temperature, so it can be used as such. At a minimum, the junction temperature should be accurate to the junction temperature. Maybe a glob of thermal goo will help the MCP9800 achieve the same temperature as the junction. The MCP9800 is sitting right between the connectors, so this would be easy.