I have a 2V regulator circuit which is used to drive a microcontroller (EFM32G222F128). On the output of this regulator I have a delay switch type circuit (see image below) which is used in order to allow the reservoir capacitor to charge enough in order to deal with the initial start up current of the \$\mu\$C.
The circuit as it is works fine, however, should, for any reason, the \$\mu\$C draw too much current (the regulator is only rated to allow a low current out) the output of the regulator will drop below 2V, thus causing the \$\mu\$C to lose power.
When this happens the voltage appears to latch at ~1.7V and power needs to be removed for a few seconds before the circuit will power up again properly.
I have put this down to the NX2301P not switching off properly once the voltage has dropped below 2V. This is sort of part of a bigger issue with this delay switch...
Say I remove power to the circuit, the regulator output voltage drops away slowly (a couple of seconds) and once it actually passes the 2V mark it drops more quickly down to about 0.5V where it only trickles away and I never really see it drop to zero without getting really bored waiting. If I try to turn power on during the 'quick discharge' region, the output won't go back up to 2V, it will latch at the 1.7V mentioned previously. I have to wait for the output to level out to around 0.5V before it will be able to go back up to the 2V steady output.
Is there a way I could, preferably using discreet components, improve the delay switch so that if the voltage output of the regulator drops below 2V, the PMOS will turn off and allow the circuit to sort of reset and get up to 2V before turning back on?
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