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Need Power supply to get simple +5V in the car

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Zedman

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low noise 5v car psu

Hi guys,

I would like to build a PSU for my MP3 player to use it
in my car.
I would like to get 5V from 14.4V, and remove the ignition noise.
It has to provide about 2 amps max, to drive the project and a
notebook hdd.
Is it possible to build one that won't get hot while not in use,
i mean the PSU turned on with no "consumer" on it?
(for example a 7805 gets very hot while dissipates the difference
betweeen 14V and 5V)

I'm not very familiar with PSUs,
thanks,
Zed
 

Re: Power supply to get 5V in the car

take a look at this.
**broken link removed**

i`ts for a car mp3 player too :D
 

Re: Power supply to get 5V in the car

Some more links, to two simular designs.

**broken link removed**
**broken link removed**

re. Me
 

Re: Power supply to get 5V in the car

Thanks guys,

but my player is a standalone MP3 player, so I need only
+5V from the +14.4V, and the noise reduction
in some simple design like with LM2576 or similar.

anyone please can help?
thanks
Zed
 

for an mp3 player about 1 amp is enought.so use a simple 8005 with a big heatsink :D
 

:wink: Here is a circuit designed for you download the PDF file and have a nice day. :wink:
 

How about a simple LM7805 with a respectable heatsink, It only needs a few discrete parts and very simple & efficient also.
 

I made it with LM2576-5.0, it's cool it has on/off pin,
and needs only a small heatsink, provides up to 5 amps, and needs only 5 external parts.
I built it and really it just gets warm with a 2x2 cm heasink. Thats what i need! :)

Zed
 

yes the circuit can be built using LM2576 step down regulator.

please take into consideration fallowing points.

1: Linear regulator = Very Low noise and ripple BUT less efficiency.
2: switching regulator = high efficiency BUT High noise and ripple .

it is up to the user to determine his choise depending upon application,
and for audio circuits a pure linear design will give better performance. :wink:
 

rauol,

now you made me sad...
because it works fine with the PC's 12V but i did not try it in the car yet...

Zed
 

Zed sorry if my post made you sad.

but different hardwares are designed for different platforms. for example the products designed for use with PC have better noise rejection features Etc.
as for small portable products i think they are battery powered which has practically no noise on it.

that is why i recommended a linear regulator.
As a rule of thumb products can always run from Linear powersupplies but the same cannot be Guaranteed with the use of switching regulators unless you try it in your application. :(
 

Very simple circuit.
Just buy one 2N 3055. 5.6v 1W zener & one resistor of 1k .5 watt.
Connect + to collector, From collector to base connect 1k resistor, Then connect zener diode (ZD) from base to ground. Check the polarity of ZD from any text book. Take the output from emitter. u will get roughly 4.95V. I think this is the sim[plest circuit possible with heavy current of 5A if required.
MP
 

I used MAX724 for my mp3 player... You can get it from www.maxim-ic.com, as a sample... It works up to 5A....
 

And what about the ignition noise?
should i use some isolator transformator?
or a noise reductor capacitor?

Zed
 

u will need one inductor and capacitor to reduce ignition noise.
Many car audio devices hv this inductors built in their power cable.
MP
 

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