[TriEmbed] TriEmbed Digest, Vol 16, Issue 18 - Power regulator questions

[Charles McClelland]

Michael, 

Thanks for taking a look at the power supply thread,  as my projects run on batteries, I have put some time into this.

Here are a few thoughts:
	- Like you, my circuits draw a relatively small amount of current.  I developed these tests at a higher current so they would not take a month to run
	- your current regulator (MCP1700-3302E) is Linear so it will dissipate - read waste - power equal to the product of the difference between Vin and Vout time current (Eqn 6-1 in data sheet)
	- This is where I started but I decided to move to a switched power supply for three reasons:
		- They are battery omnivores - since the TPS63031 is both boost and buck and is over 90% efficient over a large range (1.8-5.5Vin) - I can throw all sorts of batteries at it
		- As they are more efficient, they should throw off less heat - potentially a big deal since I put them in a box and bury them
		- This supply can handle from very small 25uA to 800mA currents

As with all things in Engineering, there are some trade-offs I had to accept:
	- more expensive
	- QFN packaging - ugh
	- weird and exotic new component required - an inductor - no really!  There are a bewildering number of choices here!

Some suggestions:
	- I would be happy to loan you my test rig which you could use to test your current power supply and compare it to the three I made.  
	- I added the Excel spreadsheet with the full set of tests and results to the posting on the Triembed.org site
	- I could give you a TPS63031 breakout board so you could test the supply in your circuit without the pain of soldering - I have some extras
	- You could look at commercial options such as the little breakout boards from Pololu - I have one of these you could borrow if you like

Hope this helps.  

BTW, my next step in my power supply obsession is to add a battery fuel gauge to the circuit so my Arduino can check it and so I could use LiPO batteries with more confidence.


Chip



On Sep 16, 2014, at 5:00 PM, triembed-request at triembed.org wrote:

> MCP1700-3302E

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