June 6, 2010
about 10 months ago
Product 11360 won’t turn itself on automatically if it completely discharges, and will turn itself off if there’s not enough load. You can solve the latter problem by adding load, but that means you get less runtime (for a 15mA load, 11360 is equivalent to the $25 cheaper https://www.sparkfun.com/products/341), so it’s not really a solution.
In more practical terms, this one will run an unmodified Arduino Pro Mini 328 continuously for a week on a full charge, while the 11360 will run it for only a few seconds at any charge.
You could take 11360 apart, cannibalize its battery goodness, and reverse engineer or replace its charge controller–but you would have to do some work like that to make the products equivalent for this kind of price comparison. Out of the box they do not behave the same way at all.
11360 is designed to recharge smartphones with huge built-in batteries, and can also be used for things like big USB fans or flashlights–anything with a big enough continuous minimum load. It’ll run a heavy USB device like a Raspberry or BeagleBone for a while too–but if you’re too aggressive at saving power, it will shut off without warning.
Tutorial - PowerCell Quickstart Guide
about 10 months ago
The schematic has it pulled high with a 10K resistor. The TPS61200 data sheet says you pull PS low to make it active.
As for what it does…it looks like it makes a tradeoff between power efficiency and output voltage accuracy. If you pull PS low, you get more ripple on the output, but more power efficiency with smaller (1mA-10mA) loads. The device uses shorter bursts of higher current because it’s most efficient between the middle and top end of the operating range.
News - July Caption Contest
about 2 years ago
I don’t care what the data sheet says! I’m still not 100% sure it’s safe to use our new laser module to heat beverages. Shouldn’t we be wearing safety goggles or something? Or at least open the can first?
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