Anyone ever make a 12VDC powered ATX power supply
paysonbadboy
Posts: 81
I use a few ATX, or actually the mini-ATX PC based systems in my work vehicle and in my personal truck.
Both of them I run inverters for now and have no problems other than having to shut off the inverter and possible battery run downs if·I leave it on too long.
First I'll explain what·I do with them:
I know most people will say "use a lap top" but in my work vehicle I alread had one lap top stolen and my other one was so old that·I just threw in a small PC system in that·I had no use for at home. Plus I can upgrade and do anything with a PC based system. Running a 15" flat panel and small keyboard on a mount·I welded up it's been great. the only money·I have into that set up is the 15" flat screen. The computer was spare parts for me and the keyboard, WiFi, mouse, etc was cheap stuff to buy.
I don't mind the inverter in THAT vehicle because I run the inverter for other things like to charge my 18Volt battery charger and other things. But I'd like a power supply I can have shut·down to very minimal power usage automatically which right now·I have to turn off my inverter each evening.
The second PC system is in my Dodge 4X4.
This one is NOT spare parts but I don't have too much $$ into it so far.
I'm running a mini-ATX with one hard drive and one DVD-RW. It has a Wi-Fi with external antenea and all operated by a RF remote control and a in dash TOUCH SCREEN flat panel monitor I installed where my stereo used to be. This set up runs my GPS navigation, and most importantly, my music via the 2,000 mp3's and numberous DVD movies·on the 120 Gig hard Drive (with tons space left over). I also have Wi-Fi to go "Net Stumbling" when I need to and can copy a DVD movie in 30 minutes if I'm at someone's house away from my home PC, etc. I LOVE my PC based media system and it has worked great for the last 6 months so far.
This one I want the power supply to run efficiently and be able to shut down/sleep automatically. Using the inverter is a pain on this because I have to remember to shut off the inverter which is under the rear seat close to the PC system. The PC system is NOT in a case. It's intergrated behind the rear seat (4 door truck).
Now I have read up on how the ATX power supply works with the motherboard as far as turniing on and off, etc·so I have pretty much figured that part out. I also could EASILY just make it turn off the inverter automatically (having the 5VSB wire powered to the MB at all times) but·I really want to just make a power supply that simply runs off of the 12VDC in my truck (got a deep cycle battery for it) to make the 12VDC, 5VDC, 3.3VDC, and of course the -12VDC.
Anyway. I think·I know how·I am going to build it, but I also know many people here have done lots of neat things. So I thought I'd see if anyone in here had taken on such a task just to share ideas.
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http://www.paysonarizona.net/
Both of them I run inverters for now and have no problems other than having to shut off the inverter and possible battery run downs if·I leave it on too long.
First I'll explain what·I do with them:
I know most people will say "use a lap top" but in my work vehicle I alread had one lap top stolen and my other one was so old that·I just threw in a small PC system in that·I had no use for at home. Plus I can upgrade and do anything with a PC based system. Running a 15" flat panel and small keyboard on a mount·I welded up it's been great. the only money·I have into that set up is the 15" flat screen. The computer was spare parts for me and the keyboard, WiFi, mouse, etc was cheap stuff to buy.
I don't mind the inverter in THAT vehicle because I run the inverter for other things like to charge my 18Volt battery charger and other things. But I'd like a power supply I can have shut·down to very minimal power usage automatically which right now·I have to turn off my inverter each evening.
The second PC system is in my Dodge 4X4.
This one is NOT spare parts but I don't have too much $$ into it so far.
I'm running a mini-ATX with one hard drive and one DVD-RW. It has a Wi-Fi with external antenea and all operated by a RF remote control and a in dash TOUCH SCREEN flat panel monitor I installed where my stereo used to be. This set up runs my GPS navigation, and most importantly, my music via the 2,000 mp3's and numberous DVD movies·on the 120 Gig hard Drive (with tons space left over). I also have Wi-Fi to go "Net Stumbling" when I need to and can copy a DVD movie in 30 minutes if I'm at someone's house away from my home PC, etc. I LOVE my PC based media system and it has worked great for the last 6 months so far.
This one I want the power supply to run efficiently and be able to shut down/sleep automatically. Using the inverter is a pain on this because I have to remember to shut off the inverter which is under the rear seat close to the PC system. The PC system is NOT in a case. It's intergrated behind the rear seat (4 door truck).
Now I have read up on how the ATX power supply works with the motherboard as far as turniing on and off, etc·so I have pretty much figured that part out. I also could EASILY just make it turn off the inverter automatically (having the 5VSB wire powered to the MB at all times) but·I really want to just make a power supply that simply runs off of the 12VDC in my truck (got a deep cycle battery for it) to make the 12VDC, 5VDC, 3.3VDC, and of course the -12VDC.
Anyway. I think·I know how·I am going to build it, but I also know many people here have done lots of neat things. So I thought I'd see if anyone in here had taken on such a task just to share ideas.
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http://www.paysonarizona.net/
Comments
Rick
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My Computer Specs
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"I had no professional training, I gave it my all, I have no regrets" -William Hung
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I'll check out the search. I forgot all about checking back here until tonight.
I messed around the other day with what I already had here at home. I'm too poor right now to buy lots of goodies as my wife and I missed work last month repeatedly seeing her grandfather in the hospital and then going to his funeral. Plus in my kind of work it was my slow tme. BAD TIMING. But I'm busy again and should be able to buy stuff again in the next few weeks.
I took some small gauge magnetic wire and wound a toroid tranformer. Drove a mosfet with a 555 and then regulated the output to -12VDC. So when I build my control I'll have to incorporate that switching power part into it for the -12VDC. Only thing that sucks about using a 555 is the pulse width is so wide. I can alter it somewhat by using diff value resistors but I'll probably wind up using the sawtooth output from the cap on the 555 to an op amp to regulate the pulse width down where I want it (555 + op amp = cheap PWM). I could then actually make it run as a PWM but probably can just fix the pulse width and regulate with a 7912 like I want to.
I know they say you should run very precise switching power supplies but I've been running motherboards and hard drives off of cheap inverters for over a year now with no failure. And if something does die, it's cheap at Fry's to buy a motherboard..
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I bought TWO of those exact same·kits over a month ago·:P
Sorry it took so long to reply. I've been getting my *** kicked at work. No time to play with hobbies right now.
Anyway. On that board they use this little tiny surface mounted transistor or fet to power on the power supply. It overheats and lets the smoke out. There are NO heat sinks at all. The transistors are simply·laid flat in the board.
Must be made for a very low power board.
I think I'm going to make my own PWM power supply using some toroid transformers·driven by a home made PWM (sawtooth into an op amp). I think using one 555 and one quad op amp I could get 4 PWM signals to a bank of mosfets. That should be plenty of power and lowest heat generated.
After·I get a proto type working I'll make a batch getting boards etched from express PCB.
I'll let you know how it goes...
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There's that power supply I purchased.
It's pretty weak. There is not even any heat sinks WTF?
It does look to have a lot of intelligent controlling. But just weak on power output.
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OK. I pointed it out. THAT is what fries.·A LITTLE tiny switching transistor·I think. Surface mount!
It's NOT the regulators burning. I think they are more like switching transistors (maybe mosfets) amd diodes. And·I knew the solder WAS the heat sink, but also know that it would not be very much power that way.
Although under powered, it seems to have some high tech control. Like for SLEEP mode, STANDBY, etc. Maybe even shuts the PC down on low battery.
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So... WHY does IT smoke???
the first board ran for an hour or more before it fired.
the second one not as long.
Same part burnt on both.
I don't think it was meant to run a Athalon 2200+, the cooling fan, 120Gig HD, and DVD Rom on a mini-ATX board.
More like a mini-ITX I think.
Maybe I'll work on it a little bit more tomarrow. At least look through some of my stuff for some larger Toroids to wind.
And I'll bump the frequency up too.
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A 60W power supply is good for powering (2) average hard drives or (1) hard drive and an CDRW or DVD drive.
Bit still not enough.
So it's still on a small 120VAC power supply ran off of a small inverter. no problems, except that I have to switch on the inverter.
Check out THIS power supply in one of my old amps I retired. Got tired of repairing it. And it had been repaired many time before i got it.
It uses 12 IRFZ44 Mosfets to run the power to something like +/- 55VDC for the main amp (110 volt signal to the speakers!). And had a few other taps off of the toroid transformer for pre amps and stuff.
The windings shown are just for the pre amp section. Under the yellow tape stuff is the massive windings for the main amp. It's using 4 windings paralleled on a push-pull set up.
There is an array of Mosfets and about 26 output transistors just for a TWO CHANNEL amp.
It was a power hog and not very efficient.
Funny thing. well, NOT funny actually.
the fan took a dump in the trucks PC system (teach me to use an old fan when i built that). So·I grabbed the one off of here to test it. So·I went and got a new fan for it. It's ok.
Then put this fan back on this computer in my house. No GO! It never booted up again.
I either damaged the CPU when I was trying to rip that ba$tard ThermalTake off, or it didn't seat back on properly and cooked the Athlon CPU within seconds. [noparse]:([/noparse]
So. had to go buy a new motherboard/CPU last night. Got one of those AMD 64 bit boards and CPU. IT CAME with a special fan included with the CPU. This fan clamps on like a vise!
It's QUIETER than the old system.
Now I've got to buy (or borrow) Windows XP Pro 64 bit edition when·I get a chance.
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Post Edited (paysonbadboy) : 5/1/2005 9:25:32 PM GMT
what's the dimensions/weight of that bad boy!! Looks like it's taking up quite a bit of your table/bed there!
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Steve
http://ca.geocities.com/steve.brady@rogers.com/index.html
"Inside each and every one of us is our one, true authentic swing. Something we was born with. Something that's ours and ours alone. Something that can't be learned... something that's got to be remembered."
26 of them FAT output transistors and 12 Mosfets!!! You KNOW it was crammed in there!
and like I said. There is several layers of windings on that toroid under the yellow insulation they have on there.
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There are several power supply units on the market that do what you need...but most are designed around micro-atx level power output. (And when the heck will nano-itx come out?!?!?)
Ryan
It's only $169 and is a Via chipset with an embedded Via 1Ghz processor. There is a CPU heat sink but NO fan required!
I'd bet it would take less power to operate than my Athlon.
I've seen SOME power supplies made for this purpose. but they RAPE you big time since they are not something that is a dime a dozen.
I think I'll still build my own.
I found some cool new regulators in the newest Digi-Key that just came in my mail yesterday.
Some that are internal transformerless switching types that run at like 600Khz. I saw some 5 amp 3.3 ones but then I saw max INPUT voltage on most of them is only 7 volts!! I wonder how it would like 12!
It would probably die quickly!
I think the PWM switching through some transformers would be MOST efficient. So I'll keep plugging away at that when I have more time.
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