Anyone have a suggestion of your preferred voltage regulator for
deriving 3.3V from a lead-acid battery?
I am currently using a 78M33 3.3v linear regulator in a SOT-223 that
can source up to 500mA. Most of my tinkering doesn't require nearly
that much current; probably more on the order of 1-2mA typical, with
occasions of up to 40-60mA if a multi-LED display is turned on.

The big concern is the terrible conversion inefficiencies when using a
linear regulator to drop from 12-14V all the way down to 3.3V. If my
Iout is small, then the losses should decrease, but they are still
there.

Thanks for any suggestions you may have...
------------------------------------



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Look at the TPS62111 from TI.

Thanks,

Jim

_____

From: m...@yahoogroups.com [mailto:m...@yahoogroups.com] On Behalf Of
abernax
Sent: Tuesday, August 12, 2008 4:04 PM
To: m...@yahoogroups.com
Subject: [msp430] Preferred voltage regulator for lead-acid batteries?

Anyone have a suggestion of your preferred voltage regulator for
deriving 3.3V from a lead-acid battery?

I am currently using a 78M33 3.3v linear regulator in a SOT-223 that
can source up to 500mA. Most of my tinkering doesn't require nearly
that much current; probably more on the order of 1-2mA typical, with
occasions of up to 40-60mA if a multi-LED display is turned on.

The big concern is the terrible conversion inefficiencies when using a
linear regulator to drop from 12-14V all the way down to 3.3V. If my
Iout is small, then the losses should decrease, but they are still
there.

Thanks for any suggestions you may have...

[Non-text portions of this message have been removed]
------------------------------------



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--- In m...@yahoogroups.com, "Jim Carlson" wrote:
>
> Look at the TPS62111 from TI.

Well... probably a good but not the best choice!
The price is about $2.35 (for comparison).
Maybe you should have a "general" look at TI's buck converter port
folio with integrated switch. It starts with the good old MC34063 and
MC33063 for about $0,40

Don't forget a reasonable filtering at the output for little ripple on
your 3.3V supply. Or think about generating e.g. 5V with the buck
converter and an additional linear regulator, if you need an even more
stable supply voltage, e.g. for sensitive analog measurements!

------------------------------------



(You need to be a member of msp430 -- send a blank email to msp430-subscribe@yahoogroups.com )

I agree the MC34063 is a great little work horse, not the smallest
components compared to modern parts, and not quite as efficient but
cheap and easy to use in buck or boost roles, and very well documented
in AN920, less than $1 for the complete circuit.

Al

bb_stefan wrote:

>--- In m...@yahoogroups.com, "Jim Carlson" wrote:
>
>
>>Look at the TPS62111 from TI.
>>
>>Well... probably a good but not the best choice!
>The price is about $2.35 (for comparison).
>Maybe you should have a "general" look at TI's buck converter port
>folio with integrated switch. It starts with the good old MC34063 and
>MC33063 for about $0,40
>
>Don't forget a reasonable filtering at the output for little ripple on
>your 3.3V supply. Or think about generating e.g. 5V with the buck
>converter and an additional linear regulator, if you need an even more
>stable supply voltage, e.g. for sensitive analog measurements!
>
>------------------------------------



(You need to be a member of msp430 -- send a blank email to msp430-subscribe@yahoogroups.com )

Maybe an additional comment on the MC34063:

Although very cheap and easy to use, there might arise some problems
with this DC/DC converter if one does not keep in mind the operating
principle. The MC34063 does not a "real" PWM controlling for adjusting
the output voltage. Instead a simple comparator controls the internal
switch, which means that some pulses are just being skipped for
regulation which can lead to excessive ripple on the output voltage.

This does not disqualify the MC34063 but one should remember about
this :-)

--- In m...@yahoogroups.com, Onestone wrote:
>
> I agree the MC34063 is a great little work horse, not the smallest
> components compared to modern parts, and not quite as efficient but
> cheap and easy to use in buck or boost roles, and very well documented
> in AN920, less than $1 for the complete circuit.
>
> Al
>
> bb_stefan wrote:
>
> >--- In m...@yahoogroups.com, "Jim Carlson" wrote:
> >
> >
> >>Look at the TPS62111 from TI.
> >>
> >>
> >
> >Well... probably a good but not the best choice!
> >The price is about $2.35 (for comparison).
> >Maybe you should have a "general" look at TI's buck converter port
> >folio with integrated switch. It starts with the good old MC34063 and
> >MC33063 for about $0,40
> >
> >Don't forget a reasonable filtering at the output for little ripple on
> >your 3.3V supply. Or think about generating e.g. 5V with the buck
> >converter and an additional linear regulator, if you need an even more
> >stable supply voltage, e.g. for sensitive analog measurements!

------------------------------------



(You need to be a member of msp430 -- send a blank email to msp430-subscribe@yahoogroups.com )

There's one on ebay for cheap and free shipping

http://cgi.ebay.com/ws/eBayISAPI.dll?ViewItem&item=250282150191
--- In m...@yahoogroups.com, "bb_stefan" wrote:
>
> Maybe an additional comment on the MC34063:
>
> Although very cheap and easy to use, there might arise some problems
> with this DC/DC converter if one does not keep in mind the operating
> principle. The MC34063 does not a "real" PWM controlling for adjusting
> the output voltage. Instead a simple comparator controls the internal
> switch, which means that some pulses are just being skipped for
> regulation which can lead to excessive ripple on the output voltage.
>
> This does not disqualify the MC34063 but one should remember about
> this :-)
> --- In m...@yahoogroups.com, Onestone wrote:
> >
> > I agree the MC34063 is a great little work horse, not the smallest
> > components compared to modern parts, and not quite as efficient but
> > cheap and easy to use in buck or boost roles, and very well
documented
> > in AN920, less than $1 for the complete circuit.
> >
> > Al
> >
> > bb_stefan wrote:
> >
> > >--- In m...@yahoogroups.com, "Jim Carlson" wrote:
> > >
> > >
> > >>Look at the TPS62111 from TI.
> > >>
> > >>
> > >
> > >Well... probably a good but not the best choice!
> > >The price is about $2.35 (for comparison).
> > >Maybe you should have a "general" look at TI's buck converter port
> > >folio with integrated switch. It starts with the good old MC34063 and
> > >MC33063 for about $0,40
> > >
> > >Don't forget a reasonable filtering at the output for little
ripple on
> > >your 3.3V supply. Or think about generating e.g. 5V with the buck
> > >converter and an additional linear regulator, if you need an even
more
> > >stable supply voltage, e.g. for sensitive analog measurements!
>

------------------------------------



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abernax wrote:
> Anyone have a suggestion of your preferred voltage regulator for
> deriving 3.3V from a lead-acid battery?
> I am currently using a 78M33 3.3v...

Cheese, I have a half a dozen down converters for charging cell phones,
(plug in the cig lighter), from thrift stores for less than a buck
a/piece. If experimenting is the challenge, well...

Best, Dan.

--
email: y...@lakeweb.com but drop the 'x'.
------------------------------------



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One what on ebay? I prefer to know before I jump, ebay is a pain in the ass.

Al

Chetan Bhargava wrote:

>There's one on ebay for cheap and free shipping
>
>http://cgi.ebay.com/ws/eBayISAPI.dll?ViewItem&item=250282150191
>--- In m...@yahoogroups.com, "bb_stefan" wrote:
>
>
>>Maybe an additional comment on the MC34063:
>>
>>Although very cheap and easy to use, there might arise some problems
>>with this DC/DC converter if one does not keep in mind the operating
>>principle. The MC34063 does not a "real" PWM controlling for adjusting
>>the output voltage. Instead a simple comparator controls the internal
>>switch, which means that some pulses are just being skipped for
>>regulation which can lead to excessive ripple on the output voltage.
>>
>>This does not disqualify the MC34063 but one should remember about
>>this :-)
>>--- In m...@yahoogroups.com, Onestone wrote:
>>
>>
>>>I agree the MC34063 is a great little work horse, not the smallest
>>>components compared to modern parts, and not quite as efficient but
>>>cheap and easy to use in buck or boost roles, and very well
>>>
>>>
>documented
>
>
>>>in AN920, less than $1 for the complete circuit.
>>>
>>>Al
>>>
>>>bb_stefan wrote:
>>>
>>>
>>>
>>>>--- In m...@yahoogroups.com, "Jim Carlson" wrote:
>>>>
>>>>
>>>>
>>>>
>>>>>Look at the TPS62111 from TI.
>>>>>
>>>>>
>>>>>
>>>>>
>>>>Well... probably a good but not the best choice!
>>>>The price is about $2.35 (for comparison).
>>>>Maybe you should have a "general" look at TI's buck converter port
>>>>folio with integrated switch. It starts with the good old MC34063 and
>>>>MC33063 for about $0,40
>>>>
>>>>Don't forget a reasonable filtering at the output for little
>>>>
>>>>
>ripple on
>
>
>>>>your 3.3V supply. Or think about generating e.g. 5V with the buck
>>>>converter and an additional linear regulator, if you need an even
>>>>
>>>>
>more
>
>
>>>>stable supply voltage, e.g. for sensitive analog measurements!
>>>>
>>>>------------------------------------



(You need to be a member of msp430 -- send a blank email to msp430-subscribe@yahoogroups.com )

I think the OP was after a chip, but the one on ebay is definitely not
cheap, especially once shipping is taken into account.

Filtering noise on the outputs of these is not hard. I haven't used them
recently, since the vast majority of my current designs run off some
form of lithium cell, but used them in a wide array of products in the
past. One of the most interesting was a coilless (except for output
filters), transformerless 500V regulated supply with extremely low
ripple, so there is a lot more to this chip than it seems.

Al

Chetan Bhargava wrote:

>There's one on ebay for cheap and free shipping
>
>http://cgi.ebay.com/ws/eBayISAPI.dll?ViewItem&item=250282150191
>--- In m...@yahoogroups.com, "bb_stefan" wrote:
>
>
>>Maybe an additional comment on the MC34063:
>>
>>Although very cheap and easy to use, there might arise some problems
>>with this DC/DC converter if one does not keep in mind the operating
>>principle. The MC34063 does not a "real" PWM controlling for adjusting
>>the output voltage. Instead a simple comparator controls the internal
>>switch, which means that some pulses are just being skipped for
>>regulation which can lead to excessive ripple on the output voltage.
>>
>>This does not disqualify the MC34063 but one should remember about
>>this :-)
>>--- In m...@yahoogroups.com, Onestone wrote:
>>
>>
>>>I agree the MC34063 is a great little work horse, not the smallest
>>>components compared to modern parts, and not quite as efficient but
>>>cheap and easy to use in buck or boost roles, and very well
>>>
>>>
>documented
>
>
>>>in AN920, less than $1 for the complete circuit.
>>>
>>>Al
>>>
>>>bb_stefan wrote:
>>>
>>>
>>>
>>>>--- In m...@yahoogroups.com, "Jim Carlson" wrote:
>>>>
>>>>
>>>>
>>>>
>>>>>Look at the TPS62111 from TI.
>>>>>
>>>>>
>>>>>
>>>>>
>>>>Well... probably a good but not the best choice!
>>>>The price is about $2.35 (for comparison).
>>>>Maybe you should have a "general" look at TI's buck converter port
>>>>folio with integrated switch. It starts with the good old MC34063 and
>>>>MC33063 for about $0,40
>>>>
>>>>Don't forget a reasonable filtering at the output for little
>>>>
>>>>
>ripple on
>
>
>>>>your 3.3V supply. Or think about generating e.g. 5V with the buck
>>>>converter and an additional linear regulator, if you need an even
>>>>
>>>>
>more
>
>
>>>>stable supply voltage, e.g. for sensitive analog measurements!
>>>>
>>>>------------------------------------



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Onestone wrote:
> I agree the MC34063 is a great little work horse, not the smallest
> components compared to modern parts, and not quite as efficient but
> cheap and easy to use in buck or boost roles, and very well documented
> in AN920, less than $1 for the complete circuit.
>

Real men do it sans PWM chip :-)

Seriously, especially with the low power the OP needs one can just take
a CD40106, run it as a Schmitt oscillator and the feedback pulls the
input "to the side" which shortens the inductor charge-up phase when the
output reaches the desired voltage. If it has to be really precise he
could spring for a TLV431 to do the regulation.

This leaves another five sections of the CD40106 vacant. Maybe for a
low-butt buzzer, another voltage regulator or two, dazzling LED
blinkers, whatever. Ground the inputs if not used.

The nice thing is that this runs at a really low quiescent current.

--
Regards, Joerg

http://www.analogconsultants.com/
------------------------------------



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