I hunted around for a 3.3V regulator circuit for lipo's for some time on the Internet. I didn't find anything in production but maybe I didn't look in the right places.

Check out Digikey part number: LTC1540CS8#PBF-ND

They have various different packages for that part, so choose the one that you like. What I'm still trying to figure out is whether I need this part if I am using this LiPo battery: http://www.sparkfun.com/products/8483, which mentions that the battery includes built-in protection against over voltage, over current, and minimum voltage. Additionally, I am using the MCP73831 as the charger IC. Would I need something like this?

 

Welcome to the forums.

You have a thread now, as the old topic was a bit stale - http://forum.allaboutcircuits.com/showthread.php?t=39518&page=2

 

Because a new thread was created, I'm going to try to provide some more information. Here is the original thread: http://forum.allaboutcircuits.com/showthread.php?t=39518. So I am wondering if I need to use the LTC154 (datasheet) in my circuit if the battery mentions that it includes built-in protection against over voltage, over current, and minimum voltage and am using the MCP73831 (datasheet) as the charger IC. Additionally, does anyone have a few supplier or distributors of Li-Poly batteries? So far I have found SparkFun and HobbyKing (the batteries are intended for RC cars, planes, etc).

 

I bought Parkzone Li-Po battery cells and my friend bought cheap Turnigy Chinese cells from HobbyKing and they do not last long.
Now I use ThunderPower (4th generation) Li-Po batttery cells and they are very powerful and survive very many charges and discharges.
I buy them from my local hobby store. They get them from www.horizonhobby.com .

 

I am looking for more LiPo batteries that are aimed towards small portable electronics, similar to the battery that I linked earlier from sparkfun. Size is a consideration, and I don't need it to be able to 20C capable, 2C is more than enough for my application, I believe.

The reason I am considering the LTC1540 is because I want the power from the battery to be regulated as it decreases in charge over time being used. I'm not sure how well the battery from Sparkfun specifically handles the protection issues. Additionally, in my circuit I have an accelerometer that cannot go above 3.6V, but the Li-Po battery is nominal at 3.7V. Is this going to be an issue? Should I instead do a zener diode voltage regulation? Or should I not worry about it?

Also, should I include a diode in my circuit right off the battery to protect electronics, in case the battery is hooked up in reverse, though the plug is keyed for one direction?

 

I answered your questions, maybe two minutes ago, maybe on another website.

 

Can you point me in the right direction? I have never done a rechargeable Li-Po battery circuit before, much less don't want to cause the batteries to short circuit, bulge, and spit fire out. Thanks for the help.

 

There are many things done by a battery charger IC for it to be safe. Buy one.
Read about the precautions at http://batteryuniversity.com/learn/article/charging_lithium_ion_batteries

 

In my circuit, I already have a MCP73831 as the battery charger IC, but because of the slight difference in voltage (3.7V nominal from the battery vs 3.6V max for the accelerometer), I was wondering if I should use the buck-boost voltage regulator LTC1540 which is specifically designed for Li-ion/Li-Po battery charging circuits. The other benefit that I read about the LTC1540 is that it features the ability to shutdown everything if the battery drops below a certain voltage (configurable by having specific resistors and such). Or should I not worry to much about the difference between 3.7V and 3.6V for the accelerometer?

As for Battery University, that looks like an amazing source. +1 Rep for that.

 

Your accelerometer IC might be destroyed by the too-high voltage of a fully charged (4.2V) Li-Po cell.