Re: 5V regulator for batteries cheap efficient?

From: richard mullens (mullensdeletethis_at_ntlworld.com)
Date: 02/12/05 

Date: Sat, 12 Feb 2005 14:21:50 GMT

Mike Harrison wrote:
> On 11 Feb 2005 21:25:58 -0800, u035m4i02@sneakemail.com wrote:
>
>
>>I know I can't have everything, but I'm going to ask for it anyway.
>>
>>The circuit is 8 or so opamps, comparators, and logic circuits driven
>>by +/-5 V. It will run on batteries. Is there a comparatively cheap
>>(double the price? maybe triple) but more efficient regulator than the
>>7805/7905 for this application? i don't want the batteries throwing
>>all their energy into heatsinks and running out in 5 minutes. if
>>switching, it's got to have decent noisefreeness. noise above the
>>audio band is fine.
>>
>>Any suggestions? the lm2940 looks promising, but you folks probably
>>know better...
>
>
>
> How much does your product draw..? If more than a few tens of mA then only a switcher will give you
> significantly better efficiency. If a few mA, then look at the Holtek HT7150 - quiescent a couple
> of microamps, and takes input up to 24V. About US$0.30 from memory.
> Also look at OnSemi 78LC/FC series - similar efficiency but lower input range
>
>
Replaced by HT7150-1
3 microamp typical quiescent. 6 max.

Ricoh has/had some LDO regulators with quiescent current around 1 microamp eg Rx5RL - see
http://www.ricoh.com/LSI/product_power/info/selectionguide.pdf

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