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I have a project where I'd like to convert a 0.5 V, 800 mA supply (a solar cell) to at least 3 V with as much efficiency as possible. I've seen DC boost converters, but all the ones I've seen are designed for a higher voltage.

Any tips on a good low voltage one?

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You're going to struggle with only 0.5 V. Look for a different solar cell or array that can supply at least 1.5 V. There are a few existing solutions aimed at running off a single 1.5 V cell. Have a look at the LTC3400 from Linear Technology.

Note that it's hard to even turn on a transistor with only 0.5 V, so even if you could get the converter running correctly, it would be pretty challenging to bootstrap itself into starting at such a low voltage.

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  • \$\begingroup\$ Very well said, I would like to add there are many boost converters that operate well at .8 V so you can easily use two solar panels in series. \$\endgroup\$ – Kortuk Nov 28 '09 at 14:22
  • \$\begingroup\$ Definitely a good point. \$\endgroup\$ – Shawn J. Goff Nov 28 '09 at 23:30
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You're not the only one who has this problem, given the recent interest in solar energy.

Check out the TPS61200 from TI. It needs 0.5V for startup, but once started can operate down to 0.3V. I haven't used this part myself but TI's a very reputable player in the power management IC business (among many others).

Clint is correct, though, in that you'll have better efficiency (and more part choices!) if you string several cells in series to get to 1.5V or 2V.

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  • \$\begingroup\$ That's a pretty neat device. I'll have to order one and try it out. \$\endgroup\$ – Shawn J. Goff Nov 28 '09 at 16:32
  • \$\begingroup\$ I would stand behind TI support any day, nice device. \$\endgroup\$ – Kortuk Nov 30 '09 at 4:09
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Over at Electronics Exchange, Rex Logan had a great answer - the LVBoost is exactly what I'm looking for.

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