Auto-cutoff Power to Circuit

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Ser Brynden

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How can I automatically cutoff power to a 12VDC circuit after about a minute, while power is still applied to it? I'm not trying to keep it powered after main power is removed, like a delay-off circuit.

This is in regard to my circuit posted here: Help with Vehicle Audio Sound Board Design
I did a web search and found a few auto-off designs, some with 555 IC timers, but wasn’t sure how to adapt them to my circuit.
 
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Is the MOSFET required?
Yes, the PFET is the key to such a simple circuit. The PFET will switch several Amps of current with only a small voltage drop (a few 10s of mV). There are dozens of PFETS that would work in this circuit.

I just want power to cutoff after a minute and not come back on until source power is reset. It looks like the the circuit you mentioned goes off and on again.
The circuit produces an output for a duration of ~R2*C1 each time power is applied. I did it twice in a row in the simulation to show that even a momentary interruption of the input power resets the timing network for a new cycle.
 
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