Ultra low power power supply

[steevke]

Hello,

I'm working on a small hobby project and battery life is important.

Main components are an ATMega168V micro, ultra low power LCD, some op-amps with powersave, all at 3.3 Volt.

As soon as the unit isn't used, it drops into sleep mode, disables the lcd and opamps, and only keeps the RTC running. However, at that moment the power supply consumes much more power than the micro.

I've heard of people adding supercaps so they can disable the power supply and keep the micro running on the supercap. As soon as more power is needed or if powercap is nearly depleted, switch on the power supply again to recharge the cap. (I planned on using the TI tps60205 that has can be shutdown.)

Does anybody have any pointers to these kind of circuits? I've googled around a bit but don't seem to find that much information. I'm fairly inexperienced hardware wise, so any help would be appreciated.

Thanks in advance

Steven

 

[Oznog]

Your part already has skip-pulse circuit, which is a more efficient and effective implementation of the same concept.