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You will also need:
2 100uf capacitor
1 USB female connector
1 battery holder
Wires
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Are they marked ?
Please explain. Thanks.
Pin 2 Data-
Pin 3 Data+
Pin 4 Ground
However if you want to build your own you can check out this instructable http://www.instructables.com/id/12v-to-USB-adapter-12v-to-5v-transformer-great-/
Granted, it's good practice to place an electrolytic close to the load, that's primarily to improve transient response (also as noted in the datasheet) though for charging applications, load transients may be minimal (but YMMV, as always).
I recently built an iPhone solar charger. I had the same problem.
im getting mine tomorrow:) and along with that when alls said and done ti gives you other tsamples you may be interested in in the same emails. click them to get more free samples. you must choose standard ship in order to be totally free of cost.
ti only allows 5 samples per request but multiple requests may be possible. choose any type of business you want i put electronics amusement as mine.
hope this info helps those trying to build these.
sweet instructable i will post my results when my module arrives:)
I've been waiting for an easy 5V charger 'ible and finally someone made one!
Congrats man! 5*
Also (and perhaps more importantly), the data for that chip says that a resister is required between pins 1 and 4 to set the output voltage. If no resister is used, thoutputtdefaultsls to -1.79volts, which is not only wrong for USB, but is also outside the chipoperatinggn range. I don't see a resistementionednd in your write up at all, so how on earth did you get this to work?
What it does instead, is makes this instructable poorly thought out because you can't use more than a small fraction of the battery capacity. Instead of 2 x alkaline cells it should use 3, or a different boost circuit.
The datasheet says "open" in the resistor for 5 volts, so you don't have to use any.
Ragards, Bruno.
So 3x AAA would be far more efficient.
Good find on this chip. I scoured the TI site for something like this, but I guess I looked too hard under DC-DC and not this section. This chip looks really strong... Max 12W means you could adapt for an iPad charger.. Sweet!
It's probably safer to undervoltage the input than to overvoltage it....and it's also one less battery. :-/
Note that this Texas Instruments chip is designed to work with undervoltage... "anything" under 5V is boosted to 5v... but the more you undervolt, the less efficient the TI boost circuit will operate.
I proposed making the input 3xAA or 3x1.5v (nominal 4.5v input). The advantage is twofold: greater capacity, and greater efficiency in voltage conversion by the boost.
It's true that new batteries will contain > 1.5v (1.65v being common), but 3x1.65 = 4.95v. Even if the batteries were 1.7v, that is still 5.1v total which is far less than USB max of 5.5v.