ON/OFF pushbutton circuit for battery powered device

[Andy_123]

Not sure if this forum is the best place for this post, just let me know if I should move it

I am making a PIC based device that uses +5V for PIC and +3.3V for some other circuits.
Power coming from two AA batteries converted to +5V and +3.3V using TPS60120 and TPS60140.

What I need is ON/OFF switch using one (on/off) or two (on and off) pushbuttons.
Slider on/off switch is not an option, I need pushbuttons

Something like:
- ON button brings power to PIC,
- PIC bypasses ON switch, seals it
- PIC will shut device down once OFF button held for 5 seconds or no activity for a 2 minutes.

It would be better if I can make it with one button.

Can TPS's enable input be used?

Any other ICs?
Battery gives only 1.8-2.6V and any voltage drop is costly.

 

[HarveyH42]

Don't no much about PIC, and just a beginner with AVR, but seems like this could be done with an plain SPST pushbutton, SLEEP MODE, and a Pin Change Interupt. Not sure if your PIC has these features, but $1.16, 8-pin ATTiny13L does, and current draw in Power-Down sleep mode is very low, <0.1 uA at 1.8 volts.

 

[Andy_123]

I was looking at sleep mode, but I don't really want to keep these charge pumps running. At least I need to keep +5V running and this will drain battery I guess...

 

[Andy_123]

I probably needs something like this
https://www.linear.com/pc/productDetail.jsp?navId=H0,C1,C1003,C1144,P10330

or event better, because no extra ICs needed:
**broken link removed**
I can implement this one with TPS60140 and 2 diodes instead of "OR"