Feedback Input needs 250k Ohm equivalant to correctly bias diff pair of LT3652 feedback (Vfb) amplifier.
One of the 100k is a thermister (B=4250, i.e. 6.71V:50.7k@40C, 6.8365V:100k@25C, and 7.048V:357k@0C) placed on SLA type battery to match charge voltage with temperature.
When the current in both legs of diff pair are matching then the network is at threshold voltage.
Circuit board(s) I am working on with this:
http://epccs.org/indexes/Board/CC01/
