Reply by George Herold●November 26, 20192019-11-26
On Monday, November 25, 2019 at 7:41:05 PM UTC-5, John Larkin wrote:
> I have +12 from a wart, and I need -1.2 and -5 to power some analog
> stuff and ECL.
How much current? For ~$5(?10?) you can get three pin switchers that
can go negative ~100mA.
George H.
>
> I can do this
>
> https://www.dropbox.com/s/3b0iff93k1k2ct6/TPS_Inv_1.JPG?raw=1
>
>
> Problem is, I don't want to run Tina and there is no LT Spice model.
>
> It may go into burp mode at my modest load currents, so I could get a
> lot of output ripple. It might want some lead compensation too. I
> guess I should breadboard it.
>
> This will be noisy, so maybe I'll put the switchers on the bottom of
> the board, and I'd have the ground plane between them and the
> jitter-sensitive stuff.
>
> We have MIC4690 in stock. That might be a better choice. Again, no
> model.
>
> --
>
> John Larkin Highland Technology, Inc
> picosecond timing precision measurement
>
> jlarkin att highlandtechnology dott com
> http://www.highlandtechnology.com
Reply by Piotr Wyderski●November 26, 20192019-11-26
John Larkin wrote:
> I have +12 from a wart, and I need -1.2 and -5 to power some analog
> stuff and ECL.
LT3999, LT3439 or IR21531. All depends on your output power
requirements, noise figure and budget.
Best regards, Piotr
Reply by Dimiter_Popoff●November 26, 20192019-11-26
On 11/26/2019 2:40, John Larkin wrote:
>
> I have +12 from a wart, and I need -1.2 and -5 to power some analog
> stuff and ECL.
>
> I can do this
>
> https://www.dropbox.com/s/3b0iff93k1k2ct6/TPS_Inv_1.JPG?raw=1
>
>
> Problem is, I don't want to run Tina and there is no LT Spice model.
> ....
Why do you not want it? I am asking because I just discovered its
existence through your post and now I wonder what catch may be there to
prevent me from trying it out (not that I really need it, ltspice is
just OK for me, too).
Dimiter
======================================================
Dimiter Popoff, TGI http://www.tgi-sci.com
======================================================
http://www.flickr.com/photos/didi_tgi/
Reply by John Larkin●November 26, 20192019-11-26
On Mon, 25 Nov 2019 16:40:55 -0800, John Larkin
<jlarkin@highland_atwork_technology.com> wrote:
>
>I have +12 from a wart, and I need -1.2 and -5 to power some analog
>stuff and ECL.
>
>I can do this
>
>https://www.dropbox.com/s/3b0iff93k1k2ct6/TPS_Inv_1.JPG?raw=1
>
>
>Problem is, I don't want to run Tina and there is no LT Spice model.
>
>It may go into burp mode at my modest load currents, so I could get a
>lot of output ripple. It might want some lead compensation too. I
>guess I should breadboard it.
>
>This will be noisy, so maybe I'll put the switchers on the bottom of
>the board, and I'd have the ground plane between them and the
>jitter-sensitive stuff.
>
>We have MIC4690 in stock. That might be a better choice. Again, no
>model.
OK, I want a potted brick with one DC input, 12 or 24 volts, and 5 or
so DC outputs. Each output should be programmable for voltage and
polarity, either resistors or an SPI interface with nonvolatile
memory. 5 or maybe 10 watts.
--
John Larkin Highland Technology, Inc
picosecond timing precision measurement
jlarkin att highlandtechnology dott com
http://www.highlandtechnology.com
Reply by ●November 26, 20192019-11-26
On Tue, 26 Nov 2019 15:24:13 +0000, Clive Arthur
<cliveta@nowaytoday.co.uk> wrote:
>On 26/11/2019 08:18, Jan Panteltje wrote:
>> On a sunny day (Mon, 25 Nov 2019 16:40:55 -0800) it happened John Larkin
>> <jlarkin@highland_atwork_technology.com> wrote in
>> <f1sotedf4ldau7297ql7og02cvjosboihs@4ax.com>:
>>
>>>
>>> I have +12 from a wart, and I need -1.2 and -5 to power some analog
>>> stuff and ECL.
>>
>> If it is a wallwart just reverse the + and - coming from it and use a normal circuit?
>>
>> :=)
>>
>Or use an AC wall wart.
>
>Cheers
Universal-input warts are nice, with an international plug adapter
set. And AC would still be a problem, getting multiple voltages of
both polarities.
--
John Larkin Highland Technology, Inc
lunatic fringe electronics
Reply by ●November 26, 20192019-11-26
On Tue, 26 Nov 2019 15:49:03 GMT, Jan Panteltje
<pNaOnStPeAlMtje@yahoo.com> wrote:
>On a sunny day (Tue, 26 Nov 2019 07:09:43 -0800) it happened
>jlarkin@highlandsniptechnology.com wrote in
><2vfqtehak6bu7rnvue1q5aejl4qa8sf17c@4ax.com>:
>
>>On Tue, 26 Nov 2019 08:18:54 GMT, Jan Panteltje
>><pNaOnStPeAlMtje@yahoo.com> wrote:
>>
>>>On a sunny day (Mon, 25 Nov 2019 16:40:55 -0800) it happened John Larkin
>>><jlarkin@highland_atwork_technology.com> wrote in
>>><f1sotedf4ldau7297ql7og02cvjosboihs@4ax.com>:
>>>
>>>>
>>>>I have +12 from a wart, and I need -1.2 and -5 to power some analog
>>>>stuff and ECL.
>>>
>>>If it is a wallwart just reverse the + and - coming from it and use a normal circuit?
>>>
>>>:=)
>>
>>I'd need maybe five wall warts. That might work.
>>
>>Actually, there are very few negative-to-negative switching regulators
>>around.
>
>No, I should have put it better, something like this:
> http://panteltje.com/pub/wallwart_to_negative_IMG_0249.JPG
>
>Yes for more than one voltage not so easy.
I have one board that has 16 different supply rails.
This little one I'm considering would have +12, +5, +4, -1.2, and -5.
And one variable from 2.5 to 6 or so. From a 12 volt wart, probably.
Both neg supplies would be 100 mA or so. Fast parts are power hogs.
In a box this size:
http://www.highlandtechnology.com/DSS/J730DS.shtml
I'm thinking I have to put the power supplies on the bottom of the
board. I can move the board up a bit and have a 0.2" gap below.
Manufacturing doesn't mind parts on both sides.
--
John Larkin Highland Technology, Inc
lunatic fringe electronics
Reply by Jan Panteltje●November 26, 20192019-11-26
On a sunny day (Tue, 26 Nov 2019 15:49:03 GMT) it happened Jan Panteltje
<pNaOnStPeAlMtje@yahoo.com> wrote in <qrjhhk$tih$1@dont-email.me>:
>On a sunny day (Tue, 26 Nov 2019 07:09:43 -0800) it happened
>jlarkin@highlandsniptechnology.com wrote in
><2vfqtehak6bu7rnvue1q5aejl4qa8sf17c@4ax.com>:
>
>>On Tue, 26 Nov 2019 08:18:54 GMT, Jan Panteltje
>><pNaOnStPeAlMtje@yahoo.com> wrote:
>>
>>>On a sunny day (Mon, 25 Nov 2019 16:40:55 -0800) it happened John Larkin
>>><jlarkin@highland_atwork_technology.com> wrote in
>>><f1sotedf4ldau7297ql7og02cvjosboihs@4ax.com>:
>>>
>>>>
>>>>I have +12 from a wart, and I need -1.2 and -5 to power some analog
>>>>stuff and ECL.
>>>
>>>If it is a wallwart just reverse the + and - coming from it and use a normal circuit?
>>>
>>>:=)
>>
>>I'd need maybe five wall warts. That might work.
>>
>>Actually, there are very few negative-to-negative switching regulators
>>around.
>
>No, I should have put it better, something like this:
> http://panteltje.com/pub/wallwart_to_negative_IMG_0249.JPG
>
>Yes for more than one voltage not so easy.
oops zener in wrong legg
:-)
Reply by Jan Panteltje●November 26, 20192019-11-26
On a sunny day (Tue, 26 Nov 2019 07:09:43 -0800) it happened
jlarkin@highlandsniptechnology.com wrote in
<2vfqtehak6bu7rnvue1q5aejl4qa8sf17c@4ax.com>:
>On Tue, 26 Nov 2019 08:18:54 GMT, Jan Panteltje
><pNaOnStPeAlMtje@yahoo.com> wrote:
>
>>On a sunny day (Mon, 25 Nov 2019 16:40:55 -0800) it happened John Larkin
>><jlarkin@highland_atwork_technology.com> wrote in
>><f1sotedf4ldau7297ql7og02cvjosboihs@4ax.com>:
>>
>>>
>>>I have +12 from a wart, and I need -1.2 and -5 to power some analog
>>>stuff and ECL.
>>
>>If it is a wallwart just reverse the + and - coming from it and use a normal circuit?
>>
>>:=)
>
>I'd need maybe five wall warts. That might work.
>
>Actually, there are very few negative-to-negative switching regulators
>around.
> On a sunny day (Mon, 25 Nov 2019 16:40:55 -0800) it happened John Larkin
> <jlarkin@highland_atwork_technology.com> wrote in
> <f1sotedf4ldau7297ql7og02cvjosboihs@4ax.com>:
>
>>
>> I have +12 from a wart, and I need -1.2 and -5 to power some analog
>> stuff and ECL.
>
> If it is a wallwart just reverse the + and - coming from it and use a normal circuit?
>
> :=)
>
Or use an AC wall wart.
Cheers
--
Clive
Reply by ●November 26, 20192019-11-26
On Tue, 26 Nov 2019 00:57:20 -0800 (PST), Klaus Kragelund
<klauskvik@hotmail.com> wrote:
>Sounds like low current
>
>Why not a switched capacitor solution?
I need voltage conversion and fairly high currents, which charge pumps
aren't very good for. And they tend to be spikey noisy.
--
John Larkin Highland Technology, Inc
lunatic fringe electronics