Thread: found plans for 86W ATX DC-DC

I dont mind taking pics of my powersupply since i have 3 of the arise acd-865v onces.

Well, maybe that's a start..
Let's hope that all the components are good/clearly labeled, and
the components are globally available.

Oooh and make sure it can power UP a HD,CDrom

Would 5a do ?
Or do you need more.
(I guess, when we/someone is designing this, and he is able to produce like 5a, he also could produce 10a)

Come'on people.. 'Join the battle !!!'

Greetz

Like I said in another post, My supply is based off of the 2587 and the limit of the part is 5 amps. That means that the most energy it can put into a coil is limited by a maximum of 5 amps. When you charge a coil, the duty cycle determines the max current that will go into the coil. If you exceed that current, you risk damaging the part. A coil ramps up in current when you apply a voltage across it. EE stuff: A Cap can't go through an instant change in voltage, inductor can't go through an instant change in current. IE. current ramps up.

I am using a low dropout regulator in the supply I built. If you want to by-pass the step up portion of my +12 volt rail, you can have a supply that outputs 12 volts at 5 amps with an input of 13.5 volts.


Like I said in another post, this supply will supply 3.3 amps with an 11 volt input and 2 amps with an 8 amp input. You could probably peak the current draw at 5 amps provided the input was at 14 volts, etc.


I know it is taking me forever to do this, but I am sorry and I just ask you bear with me, you probably won't be dissapointed.

Jeff_

I dont mind waiting, i know now for sure you are working on it...kool

There are NO parts that can suplly high current for 12v line if you want to use voltages below 12v ih the input.So there are three types of parts we can use: linear regulators,flyback regulators or step-up controllers.
Linear regulators need more than 12v in the input,so we can't use them.Flyback regulators require transformer,and the more current you need the bigger is transformer,but you can get max 2-3 A.Third way is to use step-up controllers,like MAX1771. This part use 5v in the input (which we can produce high currents with MAX787),and supply 2A RMS.This what I did,after building sproggy's PSU and disappointed with 12v section of it.
There are no parts that can supply more than 2A,so if you need more current use more MAX1771.If you need very high currents (5-7A) good-designed circuit using flyback regulators with appropriate transformer is the only way!

Originally posted by Dima:
[QB]This part use 5v in the input (which we can produce high currents with MAX787),and supply 2A RMS.This what I did,after building sproggy's PSU and disappointed with 12v section of it.
QB]

I don't think it is very efficient to cut into your 5 volt line to get your 12 volt line. I used an inductor based step-up from the 8-14 volt input to get to 14.5 volts and then used a linear post-regulator to get to 12. even if the input goes to 17 volts, you will still get 12 volts out. The output of the step up will be greater or equal to the input. as the input goes from 8 to 14 the output stays 14.5. as the input goes to 14.5 and above, the output just follows it. So using a linear regulator on the ouput is not a problem. If the computer is booting when you start your car, (if you are drawing more than 2 amps), that is when there would be a problem. Plus the noise characteristics of using a linear post regulator is an added advantage. Like I said in another post, I tested my supply at 3.5 amps (on the 12v output) for 5 minutes with a 12 volt input and it did just fine (with >75 percent efficiency).

Jeff_

Hmm this power supply is even BETTER! it seems to have a built in UPS when you are starting the car and voltage drops...

http://www.mecalc.co.za/MODACS/PM10.html

At the very bottom of the page it says:

Last updated: 06.10.1999

I wonder if we could pick up where they left off....

have you seen this DC/DC suply? :
http://www.mecalc.co.za/MODACS/PV10.html

5v @ 50A
12v @ 18A

this is what I want... k maybe a bit overkill but still....

Why can't someone design an ALL IN ONE PSU. That you can attach a small second battery to in case voltage drops too low ( i.e. while turning on the car) and a timed shutdown circuit when you take the key off the ignition (by setting up WinMe to hibernate or shutdown when power button is pressed) .

I have seen these plans out there but why cant someone put em all together into one awesome package??? hehe is that asking too much?