It''s hot as hell in here
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Posts: 46,084
Hi Chilton,
As you know, the more voltage the regulator drops, the hotter it gets.
Unless... it is a switching regulator. A switching regulator uses an
inductor to store and release energy so that you get a regulated output with
very little energy "lost".
Normally these are semi-difficult to design, but TI just bought a company
called PowerTrends that makes little modules that are ready to go. Some take
an external cap or zener and some don't. Some plug right into a 7805 slot.
Downside? Not cheap. Can be hard to get (although once TI ramps up, maybe
better). And a lot of noise if you are doing A/D you'll have to filter the
daylights out of it. A lot of noise being a relative thing, mind you.
Go to digikey.com and look up PowerTrends and you'll find them. We recently
did a design for a client that hooked up to 28V and they ran cool as they
could be.
Regards,
Al Williams
AWC
* Floating point math for the Stamp, PIC, SX, or any microcontroller:
http://www.al-williams.com/awce/pak1.htm
>
Original Message
> From: chilton@t... [noparse]/noparse]mailto:[url=http://forums.parallaxinc.com/group/basicstamps/post?postID=-N6DJDwhdQ0qX8Wwuk6hHhxYy0kmkvb-y3QHs9HuMkGRvHNR2vbqM6tBjnBIWDf0TBRIRRg]chilton@t...[/url
> Sent: Tuesday, March 06, 2001 12:00 AM
> To: basicstamps@yahoogroups.com
> Subject: [noparse][[/noparse]basicstamps] It's hot as hell in here
>
>
> Oh great ones,
>
> I am struggling with heat issues in one of my projects. Several people
> have offered solutions, but the problem really boils down to this:
>
> I have a 12v LCD screen being powered by a 12v battery. I would like
> to use a smaller battery, but I'm a little unclear how all of this
> power conversion stuff works. Right now, we have 5 other circuits
> inside the housing, all deriving power from the 12v battery. But,
> those are all 6v circuits, so I run the 12v through a voltage
> regulator, which of course generates gobs of heat. This intuitively
> doesn't seem like the right course of action, as it seems any time I
> generate heat 'just for the hell of it', I'm losing power. I didn't
> sleep through all of my physics classes :-)
>
> Can I use a smaller battery than 12v to power this? I know amps are
> important, too, the power issues here just confuse the heck out of me.
> I'm a software guy--this hardware stuff is too hard for my feeble mind
> to understand. If I wanted to use a smaller voltage power source, how
> can I obtain the higher voltage? And would doing that get rid of my
> heat problem?
>
> Mocking me for my lack of understanding is OK, just taint it with a
> little info and/or schematics for me to go on.
>
> Thanks,
> -Chilton Webb
>
>
>
> Your use of Yahoo! Groups is subject to http://docs.yahoo.com/info/terms/
>
As you know, the more voltage the regulator drops, the hotter it gets.
Unless... it is a switching regulator. A switching regulator uses an
inductor to store and release energy so that you get a regulated output with
very little energy "lost".
Normally these are semi-difficult to design, but TI just bought a company
called PowerTrends that makes little modules that are ready to go. Some take
an external cap or zener and some don't. Some plug right into a 7805 slot.
Downside? Not cheap. Can be hard to get (although once TI ramps up, maybe
better). And a lot of noise if you are doing A/D you'll have to filter the
daylights out of it. A lot of noise being a relative thing, mind you.
Go to digikey.com and look up PowerTrends and you'll find them. We recently
did a design for a client that hooked up to 28V and they ran cool as they
could be.
Regards,
Al Williams
AWC
* Floating point math for the Stamp, PIC, SX, or any microcontroller:
http://www.al-williams.com/awce/pak1.htm
>
Original Message
> From: chilton@t... [noparse]/noparse]mailto:[url=http://forums.parallaxinc.com/group/basicstamps/post?postID=-N6DJDwhdQ0qX8Wwuk6hHhxYy0kmkvb-y3QHs9HuMkGRvHNR2vbqM6tBjnBIWDf0TBRIRRg]chilton@t...[/url
> Sent: Tuesday, March 06, 2001 12:00 AM
> To: basicstamps@yahoogroups.com
> Subject: [noparse][[/noparse]basicstamps] It's hot as hell in here
>
>
> Oh great ones,
>
> I am struggling with heat issues in one of my projects. Several people
> have offered solutions, but the problem really boils down to this:
>
> I have a 12v LCD screen being powered by a 12v battery. I would like
> to use a smaller battery, but I'm a little unclear how all of this
> power conversion stuff works. Right now, we have 5 other circuits
> inside the housing, all deriving power from the 12v battery. But,
> those are all 6v circuits, so I run the 12v through a voltage
> regulator, which of course generates gobs of heat. This intuitively
> doesn't seem like the right course of action, as it seems any time I
> generate heat 'just for the hell of it', I'm losing power. I didn't
> sleep through all of my physics classes :-)
>
> Can I use a smaller battery than 12v to power this? I know amps are
> important, too, the power issues here just confuse the heck out of me.
> I'm a software guy--this hardware stuff is too hard for my feeble mind
> to understand. If I wanted to use a smaller voltage power source, how
> can I obtain the higher voltage? And would doing that get rid of my
> heat problem?
>
> Mocking me for my lack of understanding is OK, just taint it with a
> little info and/or schematics for me to go on.
>
> Thanks,
> -Chilton Webb
>
>
>
> Your use of Yahoo! Groups is subject to http://docs.yahoo.com/info/terms/
>