Some basic thoughts -
1) Linear regulators generally speaking, lower noise, lower efficiency, most simple,
layout insensitive (to some degree).
2) Charge pump regulators noisy, simple.
3) Buck/Boost noisy, layout sensitive, more efficient, parts count can be higher.
4) If you have very low level signals linear more forgiving, excellent PSRR, switching topologies more
5) Set a battery life goal, that then leads you to an allowable efficiency target.
6) TI, LTC, so many others have design/selection tools that do an excellent job of
helping with design, selection, even thru thermal considerations. Webench......
7) Caps, pay attention to actual datasheets, not all caps are equal. Your are especially concerned with ESR
in switching designs. Also some regulators have a minimum requirement on output cap ESR.
8) L's, their losses to be looked at vendor to vendor.
9) Pick synchronous where ever possible (for efficiency, catch diode is a switch, not a diode). If using diodes
pick fast recovery, schottkys.
You have a lot of options and tools at vendor websites.
If you wind up switching, and need low noise for low level, great bulk caps
are polymers, an order of magnitude better ESR vs F curves over Tanatalum.
Lastly if you go switching layout very important, google
"switching regulator layout considerations", there is lots
of application notes and help on this topic.
Thanks for all the input dana.
Battery life is of great concern. I would prefer to use a linear LDO regulator for simplicity and lower noise, but it's my understanding that a 3.7V LiPo will range from 3.9-2.7V while in use. Thus I couldn't get maxium operating time for my device with a LDO.
I'm looking at using TI's TPS63001 buck/boost converter to provide the first stage of power, and to power my digital components (PSoC 3 and BT module). It's fixed at 3.3V, has small footprint (3x3mm QFN10), and only requires one inductor plus filter caps.
Would this be a good choice for powering the PSoC from a 3.7V LiPo battery ?
That looks like a good starting point, although there are buck/boost parts
out there that have multi outputs, Micrel for one.
To develop + 1.5 a zener if thats accurate enough. To get - 1.5 one approach
is to use a clk or pwm output and a diode-C network to invert voltage. Like
these basic approaches.
See attached diode inverters.
Just diode network.doc 40.5 K