Is there a simple IC for disconnecting a power source?
Common terminology for such devices is &quot;load switch&quot;
For example NCP3902 Load bidirectional load switch
For this particular application, it doesn't seem that you need a bidirectional switch as the main requirement is to be able to stop the capacitor from discharging into the load when the logic signal is low. It is probably acceptable if the capacitor charges if the 12V supply is above the voltage of the capacitor even if the control signal is low.
This can be achieved with a single P-channel FET arranged as a high-side switch. There will be a small discharge current from the 12v rail when the capacitor is turned on, but none when off.



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