I am using a a TI TLV3202 comparator (U2B) with a bridge circuit as shown in the schematic below.
After power-up and when RLS is approx. 50 k\$\Omega\$ range things seem to work - the voltage at TP13 varies with RLS. However, if RLS goes to approx. 1M or is open circuited, the voltage at TP13 goes to approx. 5V (as expected), but then STAYS at 5V, regardless of the resistance of RLS. In other words, it seems that the positive input of the comparator latches 'high'.
What could be causing this?? The lead length of the positive input is relatively long (~3 in) - could this be some sort of parasitic capacitance feedback effect from the output? If so, is there a way to address it without laying out the board again?