simple PSU Question..

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wanna build a PS. for a small amp. which runs at about 12v.
(11-14v. range), with a max. current consumption of 5A

ive one trans. 12v. rated at 10A, a 6A bridge and as much
capacitance as needed..
how to achieve agood regulation? ,volt. regulators above 1.5A
arent available in here, so can i just use a 12v. zener diode??!
or maybe theres better solutions?

thanks all..
 
I`ll take it is an automotive amp....for one thing they do not need a regulated supply there is one built in.

all this amp wants to see is a voltage source between 11-17 vdc and enough amperage available from the source

I would rectify and filter your power supply and thats all that is needed


DIRT®
 
stupid geocities server
 

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Marvellous said:
This circuit should Work for you!:cool:
The value of C2 is dependent on your input voltage
and should be preferebly more than your input Voltage:nod:


aah, u mean to use one of those lm7812 volt. regulators for ex.
combined with a 12v. 10A passing transistor..

so any recommendations about the transistor??
and what about the filtering capacitance?
 
deepanger said:



aah, u mean to use one of those lm7812 volt. regulators for ex.
combined with a 12v. 10A passing transistor..

so any recommendations about the transistor??
and what about the filtering capacitance?


I recommend to connect one diode in series with pin #2 of the 7812. With this modification You can get 12V output egzactly. The series pass device can be any high power NPN device, such as TIP35/BD249/MJ15024 etc.

Sajti
 
Hi,
the circuit of post6 won´t put out + and -12V (and so 24V).
It´ll put out some 11.6V cause of the regulator (12V) and the Vbe of the transistor (so -0.6V).
If there would be a theoretical 24V the cap would go poooof.:bigeyes:
The input -DC voltage should be ground and therefor the -12V out as well. That would work.

I think it´s very important to talk about the application the PS is for. Is the current draw permament?
If it´s an automative amp listen to JoeDirt.
You´ll just need a 14V supply which can deliver BIG currents.
Most cheaper automotive amps don´t like low battery voltages like 11V cause the switching supply has to work under extreme condition.

Jens
 
Inthis case just add 2.7V zener in series between the pin #2 of the 7812, and the ground. With it the regulator gives 14.7V, and the ouput device takes 0.7V, and the final result will be 14V.
Better solution can be with LM317, and some pot to adjust the output .

Sajti
 
so.. ive to clear up some things ,
1st its acar amp. which runs at 12v. ,imean +12v and ground
so dont need 24v split rails..
theres no SMPS inside the amp. as the ics runs direclty from the
12v. source, the ICs is TDA1519C , the whole amp. is 22wattx2
and has a 5A fuse..
iuse it here at home to drive just one 4ohm small 8" sub. for my
pc sound sys. ,and thats why i wanna build it a good PS.

so any changes would be made due to this??
thanks again..
 
IMO I´d just take a 9-10VAC transformer and 10000uF or more to supply the thing.
I have used a TDA1519C myself (actually the first kit I bought) and it sounded OK with little speakers for the PC.

BTW: The TDA1519C can take up to 17.5VDC supply voltage but taking offload voltages into account I wouldn´t use more than 10VAC transformer. I´d use 25V caps as well.

Jens
 
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