nikarasumaruda 
Hello,
I'm looking for instructions/tips on how to set up one momentary switch to toggle power from 'on' to a low current standby mode ('off' to folk who don't know better) - this is for an atmega16 circuit.
I'm not sure what search terms to use though, hard to search for !
Any hints or just the name if any of this setup/mode appreciated.
:wink:
gchapman At the semiconductor manufacturers the terms are:
Push Button Controller
Push Button Controllers
On/Off Controller
ON/OFF Power Control
There are at least several circuits that do this if one does not want to use a does-all IC.
'soft' power up. What do you want to switch?
note that 'off' and low power standby are two different things.
The mega16 is not the best choice for low current standby - you really want a pinchange interrupt to wake the cpu.
gahelton I'm assuming that this is a battery powered application ?
In the past, I have used a low Q current D type flip flop configured as a T type to toggle when clocked. The PB switch was connected to the clock input of the latch through a RC filter. Every time the switch is depressed, the latch toggles. The output of the latch is connected to a MOSFET to control power to the rest of the circuit.
An old style CD4013 has a very, very low Q current in static mode, so it draws nearly nothing from the battery while it "waits". But it's in a SO14 package, so it's fairly large. More modern single latches are available (like the 74AUP1G374GW,125), but Q current is higher. You can do some shopping around to find one to meet your needs.
