Features of this circuit:
- Polarity protection
- Over voltage protection
- Under voltage protection after a time limit
- Schmitt trigger on lower voltage limit
This circuits drives a power Mosfet. It drives the Mosfet on when the input voltage is with in a certain range (10.7v - 15.5v). If the voltage exceeds the upper threshold then the pwr Mos is driven off. If the voltage dips below the lower threshold for more than a set time (~3 sec) the pwr Mos is driven off. The pwr Mos will continue to be driven off until the input voltage exceeds the lower threshold by a percentage (105%). The lower voltage threshold is analogous to a Schmitt trigger.