This circuit resets lock-up processor/IC by cycling the power when it detects that the input to the circuit has been stuck at low.
To simulate, push on the switch to turn on the pulse train from the processor. The turning the switch off simulates locked processor with out put at 0V. This sets the output of the opAmp low which discharges the capacitor through the diode which pulls the output on the second opAmp low.
The RC values can be adjusted for time between reset.
