super small dc/dc step up

Ideas and questions about MintyBoost kits

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spycept
 
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Joined: Sat Apr 14, 2007 8:58 am

super small dc/dc step up

Post by spycept »

i found this board online for $10 and i was wondering if it would work in a mintyboost it would be awesome if it would cause is super small the size of a quarter allmost http://www.sparkfun.com/commerce/produc ... ts_id=8290

adafruit
 
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Joined: Thu Apr 06, 2006 4:21 pm

Post by adafruit »

yup that would probably work just fine, you'll need to add a USB jack and do the right stuff with the data lines

ketas
 
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Joined: Tue Jul 17, 2007 4:47 pm

Post by ketas »

I'm wondering what's it's efficiency?

xinsight
 
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Joined: Wed Jul 25, 2007 11:14 am

Post by xinsight »

i think the efficiency is similar to mintyboost. on the supplier page (yahoo store) they show the dc to dc step integrated in a AA battery holder and say that it is 80% efficient.

it also has an 8 pin IC, 2 capacitors, an inductor... so it looks like a comparable design.

Cheeser
 
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Joined: Tue Oct 09, 2007 5:36 pm

Post by Cheeser »

What exactly is, "the right stuff with the data lines," if doing this with an alternative 5v source, like the one mentioned above? Looking at the diagram, it looks like I need the R5 resistor to connect pin 3 and pin 4, and the R4 resistor to connect pin 2 to the 3V input... am I reading that right???


Also, in order to provide more amps (~1A), could multiple mintyboost circuits be connected to one usb connector in parallel?

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salsaman
 
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Joined: Thu Sep 27, 2007 2:53 am

so... how to mod the Vpack for iPhone charging...?

Post by salsaman »

Huh... I got one of these bodhilabs boards to build a charger into my hand crank multi-machine, but even though it puts out 5V, it won't charge my iPhone or newer iPod (but does charge an older iPod)-- just like my mintyboost before swapping the resistors for 100K's...:(

The Vpack pdf suggests adding a higher capacitance C2 for a smaller ripple:
http://www.sparkfun.com/datasheets/Prot ... blic-1.pdf
Curious is it would be a bad idea to try swapping out C2 entirely...? Anyone? Not looking forward to dealing with the surface mount stuff...

ps-- sorry for the off-minty-boost topic... should have just gotten another mintyboost kit for this project!

pps-- Cheeser, dig that sig!
Last edited by salsaman on Tue Oct 09, 2007 9:07 pm, edited 1 time in total.

adafruit
 
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Post by adafruit »

Cheeser wrote:What exactly is, "the right stuff with the data lines," if doing this with an alternative 5v source, like the one mentioned above? Looking at the diagram, it looks like I need the R5 resistor to connect pin 3 and pin 4, and the R4 resistor to connect pin 2 to the 3V input... am I reading that right???
you'll want about 30kohm impedence into ~2V
its up to you how to do that
Also, in order to provide more amps (~1A), could multiple mintyboost circuits be connected to one usb connector in parallel?
never quite works that way, its best to just get a higher-output dc/dc

Cheeser
 
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Joined: Tue Oct 09, 2007 5:36 pm

Post by Cheeser »

Oh, ok. So it doesn't matter how much is on either line as long as its total is 30k, even putting one 30k on one and none on the other? I didn't get that, thank you!

And my sig is from one of my favorite T-shirts from j!nx.

Image

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