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Re: 12VDC to 18.5VDC

Subject: Re: 12VDC to 18.5VDC
From: joseph2k
Date: Sat, 12 Aug 2006 16:46:13 GMT
Newsgroups: sci.electronics.basics, sci.electronics.design
mrdarrett@xxxxxxxxx wrote:

> 
> mrdarrett@xxxxxxxxx wrote:
>> I have an old laptop (366MHz) which takes in 18.5V @ 3A by external
>> (switching?) power supply.  (It didn't have a battery with it when I
>> bought it - got it 2 years ago for about $200.)
>>
>> I recently built an external battery pack, powered by 16 Energizer 1.2V
>> 2500mAh NiMH AA cells, to power my laptop in lieu of the external power
>> supply, and it does work.  So far I have been able to run the laptop
>> for about an hour and a half, and still going strong.  (Decided to stop
>> stress-testing at 1:15am, since I had work the next morning.)  A far
>> cry from paying $150 for a "new" laptop battery, when the laptop only
>> cost me $200.  Although, my 16 NiMH AA battery pack screams "GEEK!" at
>> anyone who glances at it...  ;-)
>>
>> For my next project, a DC-DC converter.
>>
>> So... I'd like to convert 12VDC from a jump-start car battery to
>> 18.5VDC, at 3A.
>>
>> After reading a recent thread about avoiding Maxim like the plague, I
>> went over to TI's website, entered my parameters (Input V: 12VDC;
>> output V: 18.5 VDC; current: 3A.)
>>
>> I found this from the search result:
>>
>> http://focus.ti.com/lit/ds/symlink/tps5430.pdf
>>
>> but I was a bit confused why this would have been suggested, since it
>> seems to be a step-DOWN regulator.
>>
>> Any suggestions...?
>>
>> Thanks,
>>
>> Michael
> 
> 
> Eh, no response from sci.electronics.basics; belatedly cross-posting to
> SED.  Better than multiposting... ;-)
> 
> Michael

You might want to try this part:

http://www.linear.com/pc/productDetail.do?navId=H0,C1,C1003,C1042,C1031,C1061,P24012

-- 
 JosephKK
 Gegen dummheit kampfen die Gotter Selbst, vergebens.ÂÂ
  --Schiller

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