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Topic: Help me choose a DC boost converter IC (Read 1 time) previous topic - next topic

danb35

I'm working on a Teensy-based project that I want to power with a couple of AA batteries, so I'm going to need to use a step-up circuit, and looking for an IC to handle it.  Here's what I need to do with it:


  • Input of 2 AA batteries, output of 5V DC

  • Average load of ~70 mA, peak about 135

  • Surface mount, but not too small--the MAX1674 with .5mm pin pitch was just too small for me to hand-solder

  • Minimal additional parts count

  • Cheap, if possible

  • Efficiency would be nice, but this isn't intended for constant use--10-15 minutes at a time at the most, so battery life shouldn't be a big issue



I'm looking at the NCP1402, which seems to meet all these requirements, but is there another choice that would be better?

dc42

That looks a very suitable chip, and I don't know of a better one - but I am not an expert in this field.

Be very careful how you select the inductor and output capacitor - getting them right is critical to switching regulators, especially the inductor.
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danb35

Fortunately, the NCP1402 data sheet calls out a particular inductor, which is easily and inexpensively available.  Likewise, they give specs for the output cap which should make it easy to comply.

fungus

I'd get a pre-built one off ebay: http://www.ebay.com/sch/i.html?_nkw=5v+dc+boost

I've used loads of them, they work really well.
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lemming

The tiny chips will run down to 2.7 volts. Why not run directly off the batteries(without boost) and set the brownout fuse to 2.7 volts?

danb35


I'd get a pre-built one off ebay: http://www.ebay.com/sch/i.html?_nkw=5v+dc+boost

Trying to keep everything on one (small-ish) PCB, so I don't really have room additional modules.  That would make the job easier, though.

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