Non-pushbutton supervisory IC with interrupt and enable outputs, kill input and adjustable power down timer
This simple design might work just fine. The TLV431A is a 3 pin adjustable zener with a 1.25 volt ref, but in this design it is used as a comparator. Combined with a 100K variable resistor it can be set to trip from 1.25 volts up to the battery voltage. This IC is very stable. The N-channel MOSFET is a level shifter/inverter. The 47K resistor sets the minimum drive current for the TLV431, and under a low voltage trip condition the MOSFET gate goes up to the battery voltage, so it is ON enough for the drain pin to ground the PB\ input of your controller IC.

Adjust the battery voltage (adjustable supply or dropping diodes) to a low value that you want the power to be cut off, then adjust R2 until the circuit triggers a shutdown by pulling the PB\ pin low. Now it is ready to use. It has been modified so the 'low' signal to the PB pin is just a brief pulse. When battery voltage returns to normal the MOSFET shuts OFF.

If an ON and OFF pulse is needed add a Schmitt trigger XOR gate from the CD4000 series of logic, along with the RC time delay. 







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This is the correct schematic for a output normally high, or logic '1'. Any change in the input causes a brief low pulse at the output.The MOSFET turning on or off will create a positive pulse at the first XOR gate output, so another XOR gate is used as an inverter to get a brief negative pulse. There are 4 gates per package. Unused inputs MUST be grounded.







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