Self holding circuit - Looking for improvements

Question

I have a battery-powered circuit (2x 3.7 V LiPo batteries) and I want to use a push-button as on switch by using some sort of low power self-holding mechanism. I have two possible solutions in my mind:

Option 1

This option uses a switch to enable the battery voltage and the MCU will assert the SH signal, so the transistor Q206 is turned on permanently.

Option 2

This option applies the battery voltage directly to the LDO and enables the LDO when the push button is pressed. Again the MCU will assert SH and bridge the switch.

I´m unsure which of these methods is the better one with the aspect of the current consumption. And I´m unsure if Option 2 is working very well. Maybe booth circuits can be improved in terms of current consumption. The only thing that I would improve is the value of the resistors (replace 100k with 1M). Are there any other options to improve that circuit?

Answer 1

There is no symbol for the LDO with Enable so I used a logical equivalent AND gate. SW1 is turn ON latch only with positive feedback and R3 will current limit the over voltage from the LiPo with internal ESD protection using Sch Diode clamps on EN input. C1 filters our EMI.

^{simulate this circuit – Schematic created using CircuitLab}

Answer 2

Shouldn´t the use be able to turn off the device using the same button? In that case you will also need to monitor the current button state.

^{simulate this circuit – Schematic created using CircuitLab}

This is a pretty simple solution. Don´t forget to add a fuse right next to the LiPo.