Post
Topic
Board Hardware
Re: Klondike - 16 chip ASIC Open Source Board - Preliminary
by
Enigma81
on 05/07/2013, 10:31:26 UTC
... If I added a 1of4 analog switch and used the 2 available lines then I could sequentially sense each of the 4 thermistors, allowing separate readings for each quad. I could then relay them as status values for the driver to decide what to do. IS this something that is worth added cost of a switch chip?
I would say 1 sensor for 16 chips in the center on the heatsink. The heatsink will spread the warmth more or less and a sensor in the middle will probably pick up close to the highest temp of all 16 chips.
This is better way than measure in different spot and calculate average.

1 sensor in the middle will actually always read the lowest temp of all the chips MINUS the delta T between junction and Heat sink (could be many degrees C).  The BEST thermal monitoring uses one sensor per chip, and always makes critical decisions (like over temp shut-down) based upon the highest reading - not the average.  Just because the average temperature is 'safe' doesn't mean that one hot chip isn't about to explode due to an over-temp condition.

Enigma