[Noisebridge-discuss] DC-DC Power conversion - Cheapish finds!

[Nicholas Granado]

oh my bad i'm an idiot disregard my last email. :-/

minty boost is a "boost converter" which steps up vs. "buck converter"
which steps down.

i'm terribly sorry I was just trying to be helpful.


nick


On Tue, Jan 8, 2013 at 6:01 AM, Nicholas Granado <ngranado at gmail.com> wrote:

> it might be useful to examine (it was to me) the mintyboost circuit (uses
> a buck converter). there's a great write up by ladyada here:
> http://www.ladyada.net/make/mintyboost/process.html
>
>
>
> nick
>
>
> On Tue, Jan 8, 2013 at 5:27 AM, Jake <jake at spaz.org> wrote:
>
>> For me, when i want a DC stepdown regulator up to an amp or so (maybe two
>> amps) i just grab a cellular phone car charger.  They are all the same, a
>> tiny circuitboard inside with a DIP version of the 34063 buck converter.
>>
>> up to 14 or 15 volts input, 5 volts output, just drop it in.  If you need
>> a different output voltage, just add a resistor across one of the two
>> resistors in the resistor-divider network.  If you need more than 15 volts
>> input (up to 40v) just replace the capacitor with a higher voltage (unless
>> it is already rated at least 10% higher than your working voltage).
>>
>> If you need more current, and/or want to be able to make buck converters
>> from scratch, the LM2576 is great.  There is a fixed 5v-output version (so
>> the only parts you need are inductor, diode, and two capacitors) or a
>> variable output version (add two resistors to select voltage).  It's simple
>> enough that you can put it together without a circuitboard if you're in a
>> hurry.  Just ask Zach!
>>
>> The LM2576 goes up to 40V input, and the LM2576-HV goes up to 60V!
>> Both can put out THREE AMPS of current.
>>
>> http://www.ti.com/lit/ds/**symlink/lm2576.pdf<http://www.ti.com/lit/ds/symlink/lm2576.pdf>
>>
>> Garrett, when you mentioned the 7805 you missed that we were talking
>> about PWM-style buck converters, which are up to 90% efficient.  A 7805
>> linear regulator is basically just an automatic resistor which burns up the
>> extra voltage, times the current you're using.  So, powering something with
>> 5V from a 15V power source, you're literally burning off twice as much
>> power as you're making use of (33% efficiency).
>>
>> -jake
>>
>>
>> Garrett wrote:
>>
>>> This is better/cheaper for 5V 500mA from 6.5-36V:
>>> http://www.digikey.com/**product-detail/en/V7805-500/**
>>> 102-1709-ND/1828602<http://www.digikey.com/product-detail/en/V7805-500/102-1709-ND/1828602>
>>>
>>> And the big brother for 1000mA:
>>> http://www.digikey.com/**product-detail/en/V7805-1000R/**
>>> 102-2178-ND/2352137<http://www.digikey.com/product-detail/en/V7805-1000R/102-2178-ND/2352137>
>>>
>>
>> ______________________________**_________________
>> Noisebridge-discuss mailing list
>> Noisebridge-discuss at lists.**noisebridge.net<Noisebridge-discuss at lists.noisebridge.net>
>> https://www.noisebridge.net/**mailman/listinfo/noisebridge-**discuss<https://www.noisebridge.net/mailman/listinfo/noisebridge-discuss>
>>
>
>
-------------- next part --------------
An HTML attachment was scrubbed...
URL: <http://lists.noisebridge.net/pipermail/noisebridge-discuss/attachments/20130108/eecd4b61/attachment-0003.html>