NimH AAA to 5V, suggestions?
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From: Jan Panteltje on 2 Aug 2010 11:38 I was looking for some 9V rechargeable blocks to power my sign_led display, http://panteltje.com/panteltje/pic/sign_pic/ to make it portable (put it in the car side window for example). Those are expensive, I had one but cannot find it. So I decided to build a small converter 1.2 to 5 V DC, singe AA cell about 2.2Ah should give about 10 hours.. ______________|\|_________ +5 | |/| | ---------------------------|-- Schottky | | | | 5.6_______ || ( | 5t | | | [ ] | 2t )|| (___| | | | |--- ---- || ( 2t __ __ | | | | | || | | | | | | 1.2 V - === | | | --- ----- === AA --- --- | | c NPN Si --- NiMH | |22u | ------ b |150u | | | e BC547 | | | === | | | | --- | | | | |1u | | ------------------------------------------------------- Orignal Hand drawn ASCII That works OK, does not get hot, but maybe it can be done better. Input current is about 220mA, output about 30mA Waveform at the collector is a nice assymetrical square wave, but it is a bit a 'soft' output, loading it lowers the voltage a lot, high Zi. Also for the ferrite core I grabbed some old small filter core. no idea what stuff it is made of. I do use the battery voltage in series to improve efficiency, I know there are little chips for 1.2 to 5V or 3.3V, what is a good jellybean one? Preferably one I can see with the naked eye and can buy in Europe :-)
From: Rich Webb on 2 Aug 2010 12:01 On Mon, 02 Aug 2010 15:38:53 GMT, Jan Panteltje <pNaonStpealmtje(a)yahoo.com> wrote: >I know there are little chips for 1.2 to 5V or 3.3V, >what is a good jellybean one? >Preferably one I can see with the naked eye and can buy in Europe :-) I've used Linear's LT1613 in a couple of small personal projects. They worked pretty well even with my <cough> non-ideal layout on a homebrew board. They have others that look promising that I haven't played with, such as the LT1307. -- Rich Webb Norfolk, VA
From: IanM on 2 Aug 2010 12:09 "Jan Panteltje" <pNaonStpealmtje(a)yahoo.com> wrote in message news:i36oqj$kq$1(a)news.albasani.net... >I was looking for some 9V rechargeable blocks to power my sign_led >display, > http://panteltje.com/panteltje/pic/sign_pic/ > to make it portable (put it in the car side window for example). > Those are expensive, I had one but cannot find it. > So I decided to build a small converter 1.2 to 5 V DC, > singe AA cell about 2.2Ah should give about 10 hours.. > ______________|\|_________ +5 > | |/| | > ---------------------------|-- Schottky | > | | | 5.6_______ || ( | 5t | > | | [ ] | 2t )|| (___| | > | | |--- ---- || ( 2t __ __ | > | | | | || | | | | | | > 1.2 V - === | | | --- ----- === > AA --- --- | | c NPN Si --- > NiMH | |22u | ------ b |150u > | | | e BC547 | > | | === | | > | | --- | | > | | |1u | | > ------------------------------------------------------- > Orignal Hand drawn ASCII > That works OK, does not get hot, but maybe it can be done better. > Input current is about 220mA, output about 30mA > Waveform at the collector is a nice assymetrical square wave, but it > is a bit a 'soft' > output, loading it lowers the voltage a lot, high Zi. > Also for the ferrite core I grabbed some old small filter core. > no idea what stuff it is made of. > I do use the battery voltage in series to improve efficiency, > > I know there are little chips for 1.2 to 5V or 3.3V, > what is a good jellybean one? > Preferably one I can see with the naked eye and can buy in Europe :-) > Have a look at Sipex SP6641A - I used it with 2 cells, but it is specced to 0.9 volts
From: Jan Panteltje on 2 Aug 2010 14:13 On a sunny day (Mon, 02 Aug 2010 12:01:17 -0400) it happened Rich Webb <bbew.ar(a)mapson.nozirev.ten> wrote in <0jqd5690lsg7fkt6t5lhietq8tb88p7ar7(a)4ax.com>: >On Mon, 02 Aug 2010 15:38:53 GMT, Jan Panteltje ><pNaonStpealmtje(a)yahoo.com> wrote: > >>I know there are little chips for 1.2 to 5V or 3.3V, >>what is a good jellybean one? >>Preferably one I can see with the naked eye and can buy in Europe :-) > >I've used Linear's LT1613 in a couple of small personal projects. They >worked pretty well even with my <cough> non-ideal layout on a homebrew >board. They have others that look promising that I haven't played with, >such as the LT1307. I found it with google, conrad and mouser here do not seem to have either in stock. Will look aroudn a bit more. Thanks.
From: David Eather on 2 Aug 2010 20:04
On 3/08/2010 1:38 AM, Jan Panteltje wrote: > I was looking for some 9V rechargeable blocks to power my sign_led display, > http://panteltje.com/panteltje/pic/sign_pic/ > to make it portable (put it in the car side window for example). > Those are expensive, I had one but cannot find it. > So I decided to build a small converter 1.2 to 5 V DC, > singe AA cell about 2.2Ah should give about 10 hours.. > ______________|\|_________ +5 > | |/| | > ---------------------------|-- Schottky | > | | | 5.6_______ || ( | 5t | > | | [ ] | 2t )|| (___| | > | | |--- ---- || ( 2t __ __ | > | | | | || | | | | | | > 1.2 V - === | | | --- ----- === > AA --- --- | | c NPN Si --- > NiMH | |22u | ------ b |150u > | | | e BC547 | > | | === | | > | | --- | | > | | |1u | | > ------------------------------------------------------- > Orignal Hand drawn ASCII > That works OK, does not get hot, but maybe it can be done better. > Input current is about 220mA, output about 30mA > Waveform at the collector is a nice assymetrical square wave, but it is a bit a 'soft' > output, loading it lowers the voltage a lot, high Zi. > Also for the ferrite core I grabbed some old small filter core. > no idea what stuff it is made of. > I do use the battery voltage in series to improve efficiency, > > I know there are little chips for 1.2 to 5V or 3.3V, > what is a good jellybean one? > Preferably one I can see with the naked eye and can buy in Europe :-) > LT1110 is nice, simple and seems like it will do everything you're after (supplied by arrow and farnell). It also comes in a SO or PDIP package so perfect for chucking on a lump of veroboard. (I just wish I could find the couple I have sitting around somewhere. I know I will find them - just as soon as their replacements arrive by courier :-( |