Power Supply 12v Dc regulator Help

**niralthegreat** · 02-02-2005, 02:31 PM

Hi
i am niral from india..

Problem is that i bought pw200m, and a lilliput via a friend who was traveling to india a month back. Every thing is ready but the biggest problem for me is i forgot to order the "ITPS" so cant regulate the car voltage.

the computer works perfect when the car is off. I have skoda Octivia 1.9 tdi its a diesel, the voltage fluctuation is between 12.2 to 14.5v noise less dc.

the second problem is that i dont get rare ics here like "LM1084 LDO" the best i tried till now is LM7812, LM350, LM317, LM723 and 2N3055 transistors.
i had put 6 to 8 7812s in parallel but it did not work, then i put 2 of LM350 in parallel but the common problem with them is when they are loaded the voltage across output drops to 8 to 8.5 and the system shuts down.

Now if any one you have build a very simple circuit which can regulate the voltage and is using it in there own car, then please share the circut diagram with me i am in despirate need.

Even a little reply would be a lot for me..
please relpy soon, as i have been try this since last 21 days. and i am hell tired and bugged up. Please give me perfect information as i am not a electronics expert i am a computer engg. Have just started this workshop for my 12v DC regulator.

Please Help soon...

**IntellaWorks** · 02-02-2005, 02:39 PM

Hey Niral, welcome to Mp3Car !

I'm going to have to say it's probably a good thing you forgot the ITPS, because I have nothing good to say about it. It's not intelligent enough to control the regulation for voltages close to 12v by this I mean if your car is putting out 12.2v it will bump the voltage down to around 9 or 10 volts which will cause your system to run unstable. It's a device that came out a while back and there are much more sophisticated devices available for close to the same price. Look into "carnetix 1260" or M1 ATX. Carnetix Web Page

**therussman2002** · 02-02-2005, 02:47 PM

the ITPS and the carnetix only regulate 60 watts of power, he has a 200 watt power supply

i am currently working on a simple regulator circuit, hopefully will have results of success or failure by the weekend

(just using 12 2amp 12volt regulators that have a .5 dropout, with 12 compatible heatsinks, and a couple capacitors to clean the input/output, in theory it will not start a fire in my trunk at least)

**IntellaWorks** · 02-02-2005, 02:49 PM

Oh man your right, good catch... wasn't even thinkin bout' that... I just heard ITPS... and started immediatly cursing..

**bluehcc** · 02-02-2005, 06:08 PM

Can someone design an simple 12 volt regulator circuit. I heard people saying you can added a high current transistor to the circuit will enable to use only one LM7812 chip to handle at least like 2,3 amp of current. any idea how circuit show be design??

**niralthegreat** · 02-02-2005, 11:22 PM

Every body thanks so much for this help.

But the thing is i live in India and i cant order from webs like "Carnetix" as because of the custom duty the cost of the regulator would be more than twice than the original. Instead u people can help me with a circuit which uses usual ICs so that i can make that thing in india. I need approx 9amp of current. And i have a main battery in my car of 75Ah and also have a spare battery 35Ah if this can help.

Thanks..
Niral

**waltsongs** · 02-03-2005, 10:59 AM

Here is a diagram showing multiple pass transistors connected to a standard 7812 regulator. The voltage drop across this will be close to a volt at high loads so it will never survive engine cranking. for 10 to 12 amps you could probably get by with three transistors/resistors. Low dropout regulators will not work in this circuit, I've tried it and fried it.

Walt

http://www.mitedu.freeserve.co.uk/Ci...er/1230psu.htm

**MikeH** · 02-03-2005, 11:54 AM

Guys,

the ITPS and the carnetix only regulate 60 watts of power, he has a 200 watt power supply

The PW200 provides about 60 watts of regulated power. The remainder of the "200W" is unregulated +12V which is essentially a wire from your battery/alternator directly to you computer (via the ATX power connector). Below is a diagram of what this looks like. I really don't like to bash other vendors, but this "200 watt" name is so misleading I really think it's worth point out to the new guys on the forum.

I have several customers using the P1260 to pre-regulate the input to the PW200 which will properly power an M10000-based system (<60W).

**niralthegreat** · 02-26-2005, 05:41 AM

Hello again i have been waitin long for a circuit that would work properly and give me regulated 12vdc from my car at 7amps. Please if any one has a simple circuit. I am tired of driving my car without a music system.

**MikeH** · 02-26-2005, 07:04 AM

Niral,

If you can wait just a bit longer, the "PSHARE" will be available in April. It will allow you to combine two P1260s (or a P1260 and P1280) in parallel to achieve up to 10+ amps at +12V with crank survival.