So, is this bad design, or am I onto something..? It would be nice to get some critical feedback.
I'm sketching out a battery driven circuit using a WiFi module (ESP32 WROVER-E). See attached schematic, showing only the power management. I decided to go for 3xAAA lithium cells and a linear 3v3 LDO. Lithium because the circuit might draw more current than alkaline batteries can provide.
With the energy level in Li cells i mind, I included a simple (perhaps too simple, omitting resistor and zener) reverse polarity protection (Q1) and a fuse.
The power button is a tactile pushbutton (SW2), that sets a latch (the two schmitt triggers, U1), activating Q2, thus powering the circuit. The microcontroller then does it's thing, before driving IO33 high after a given battery saving timeout, which resets the latch, turning the power off. The standby current seems to be very low (a few hundred nanoamps in preliminary tests).
Long pressing the power button should turn off the circuit immediately. The pushbutton is fed to IO36 on the controller. Since the button is connected directly to the battery (up to 5,5V), R16 and R5 reduces that voltage to a safe input level (below 3,5v, which is the specified maximum input voltage for the WROVER module).
Am I on a viable path here? Found some online resources, but would certainly be glad to receive a couple of links outlining best practices
