Post by thread:[OT] Alternative Parts (voltage regulators)

If you want high efficiency you might consider a switching regulator. There are versions available w/ low quiescient current and features like logic controlled shutdown, etc. But they're more complex than LDO's and tend to use more space. But there's some quite simple ones such as the LTC1503-2 from Linear Technology, which requires no external inductors and just 4 small caps wired to it. Disadvantage of an LDO is all the current must flow through the input; hence, they exhibit lower efficiency. -Dave Dale Botkin <spam_OUTdaleTakeThisOuTBOTKIN.ORG> on 04/11/2000 10:50:16 PM Please respond to pic microcontroller discussion list <.....PICLISTKILLspam@spam@MITVMA.MIT.EDU> To: PICLISTKILLspamMITVMA.MIT.EDU cc: (bcc: David E Arnold/SYBASE) Subject: Re: [OT] Samsung Parts (voltage regulators) On Wed, 12 Apr 2000, Russell McMahon wrote: > Of particular interest to me was a TO92 regulator (KA76L05Z) with low > dropout specs and max input voltage apparently similar to the LM2936 (which > I use due to its very low quiescent current, very low dropout, higher than > many max input voltage) and at a MUCH lower price from RS. I just stumbled upon the ICL7663, programmable (2 resistors), low dropout, <10uA quiescent current, logic controlled shutdown, and a tempo output that looks like it could be used for generating LCD contrast voltage. Works like a charm. Is there something else I should look at as well? Typically I want to use either 4xAA or a 9V battery and have it last for many months, so the 78L05 isn't a particularly good choice. The 7663 cost me a couple of bucks, but if there's something equivalent in performance and cheaper or easier to get, I'd love to hear about it. Dale --- The most exciting phrase to hear in science, the one that heralds new discoveries, is not "Eureka!" (I found it!) but "That's funny ..." -- Isaac Asimov

David E Arnold wrote: > If you want high efficiency you might consider a switching regulator. > There are versions available w/ low quiescient current and features > like logic controlled shutdown, etc. But they're more complex than > LDO's and tend to use more space. And switching regulators are *not* LDO. > But there's some quite simple ones such as the LTC1503-2 from Linear > Technology, which requires no external inductors and just 4 small caps > wired to it. Almost certainly not efficient. > Disadvantage of an LDO is all the current must flow through the input; > hence, they exhibit lower efficiency. Not exactly. In LDOs, current flows into the reference leg, and is thus wasted, *particularly* when exhibiting low drop-out. 1} Low Drop-out 2} Low reference current (efficient) 3} Modest to substantial output. Pick any one of the above. You might *just* get away sometimes with two of the above. -- Cheers, Paul B.

-----BEGIN PGP SIGNED MESSAGE----- Hash: SHA1 > And switching regulators are *not* LDO. Grrr. A flyback certainly is, in fact the input can range from well above the output through equal (try that with a linear!) and well below the output. If it dosen't break your head, you can do the same with an inverting boost configuration. -----BEGIN PGP SIGNATURE----- Version: PGPfreeware 6.5.2 for non-commercial use <http://www.pgp.com> iQA/AwUBOPSBx4FlGDz1l6VWEQKw1gCgvS5x8ddw8pbpSCtFmLsiWcqQuQIAoKGU rgRRnZu5cW45xKIIYJnOtt1t =+iPL -----END PGP SIGNATURE-----

David VanHorn wrote: > A flyback certainly is, in fact the input can range from well above > the output through equal (try that with a linear!) and well below the > output. Grrr thyself! Are we talking about one winding or two? A *single* winding flyback design to my mind generates a voltage opposite to its input, which I would class as a very large "drop-out" (taken to be the difference between input and output potential) indeed. Suffice it to say, I know what you mean, but you know what I mean. :) -- Cheers, Paul B.

-----BEGIN PGP SIGNED MESSAGE----- Hash: SHA1 At 10:29 PM 4/12/00 +1000, Paul B. Webster VK2BZC wrote: > Grrr thyself! Are we talking about one winding or two? A *single* >winding flyback design to my mind generates a voltage opposite to its >input, which I would class as a very large "drop-out" (taken to be the >difference between input and output potential) indeed. Thou didst not SAY "single winding". The inverting buck is a single winding (simple inductor) You just have to think upside down for a little while. > Suffice it to say, I know what you mean, but you know what I mean. :) :) BTW: Did I mention that I passed my Gen, Adv, and Extra 2 weeks ago? 72 hours and counting -----BEGIN PGP SIGNATURE----- Version: PGPfreeware 6.5.2 for non-commercial use <http://www.pgp.com> iQA/AwUBOPSJPoFlGDz1l6VWEQKzNgCcDO7j0msFNlAnPCrHn5add/ADBBEAnR27 x/EdNHaFXFy8pSDIzCvwhOct =bX3l -----END PGP SIGNATURE-----

>> Grrr thyself! Are we talking about one winding or two? A *single* >>winding flyback design to my mind generates a voltage opposite to its >>input, which I would class as a very large "drop-out" (taken to be the >>difference between input and output potential) indeed. > >Thou didst not SAY "single winding". > >The inverting buck is a single winding (simple inductor) >You just have to think upside down for a little while. > >> Suffice it to say, I know what you mean, but you know what I mean. :) Are we pedants allowed to TAP the single winding ? :-) RM

-----BEGIN PGP SIGNED MESSAGE----- Hash: SHA1 > >Are we pedants allowed to TAP the single winding ? :-) > >RM I can' t think of the name ofhand, but the tapped inductor version is a recognized topology. - -- Are you an ISP? Tired of spam? http://www.spamwhack.com A pre-emptive strike against spam! Where's Dave? http://www.findu.com/cgi-bin/find.cgi?kc6ete-9 -----BEGIN PGP SIGNATURE----- Version: PGPfreeware 6.5.2 for non-commercial use <http://www.pgp.com> iQA/AwUBOPn4C4FlGDz1l6VWEQJ3MACgmc1rvzMwQzNvpkVHChCZit+hbtYAniIT fU+E+/3S6JczyVCj0X2onUkp =9GA3 -----END PGP SIGNATURE-----