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Voltage Doubler

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darryl_co

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Hi,
I need a low voltage high current(6V/1A) to run a audio power amp and high voltage low current(12V/100mA) to run the control circuit from a single winding transformer wrt Gnd terminal.Using a center tap transformer would reduce the current efficiency of low voltage line.I have attached a image.Please help me!
 

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Do you already have the transformer?

Does the voltage need to be regulated?

Ron
 
What do you mean by,
Using a center tap transformer would reduce the current efficiency of low voltage line.
 
Do you already have the transformer?

Does the voltage need to be regulated?

Ron
I do not have the transformer but I want to use standard transformers available.When I mean by standard is the txs are 6-0-6 or 0-6 or 9-0-9 or 0-9 not 6-0-9 or 0-6-9.The high voltage will be fed to the input of 7812 regulator.
 
If I use a 6-0-6/1Amp (A-B-C)volts tx and wire it as a bridge between A and B and maybe a diode from C (half wave) i would not get the full current capacity of the tx

So use a 2 amp 12V CT transformer. Pretty common and available at Radio Shack it is so common if I am not mistaken. Do you need regulated voltage?

Ron
 
So use a 2 amp 12V CT transformer. Pretty common and available at Radio Shack it is so common if I am not mistaken. Do you need regulated voltage?

Ron
"2 amp 12V CT transformer" Do you mean 12-0-12(24V) or 6-0-6(0-6-12) 12v? Either ways what is the schematic? As already stated the high voltage i.e goes to the input of a 7812 voltage regulator and the low voltage just need to be full wave rectified and filtered as its for a power amp,regulation not required

Driver300 - "I used this circuit:- Voltage doubler - Wikipedia, the free encyclopedia" It seems to be a half wave voltage doubler thus reducing the output current
 
A single-ended audio amp using only 6VDC for its power supply has an output at clipping of only 0.26W into 8 ohms which is almost nothing. Two amps produce 0.52W of sound plus about 0.35W of heat for a total power of 0.87W. It draws 145mA from 6VDC when both channels are at clipping. The transformer must supply 1.2W at 6VAC.

If the amp is bridged and the stereo speakers are 4 ohms each then the output at clipping per channel is about 0.9W. The total power would be 1.5W from 6VDC and would be 2.1W from the 6VAC transformer.
 
I don't see why you don't just use a center tapped 6 -0 - 6 transformer with a full wave bridge between the ends and use the center tap as your 6 volt source. No efficiency or power handling capacity of the transformer is lost either.
 
I don't see why you don't just use a center tapped 6 -0 - 6 transformer with a full wave bridge between the ends and use the center tap as your 6 volt source. No efficiency or power handling capacity of the transformer is lost either.

That is what I was suggesting. Use a 6-0-6 transformer (12 Volts CT) with a bridge and use the CT for your 6 volts.

Ron
 
But I betcha he wants to connect the ground of the 6VDC to the ground of the 12VDC.
 
A 6 volt audio power amp, whats that from a boom box? Use or make a 12 volt amp.
 
But I betcha he wants to connect the ground of the 6VDC to the ground of the 12VDC.

Uh Oh, never thought about the common ground thing. Good point AG.

Ron
 
But I betcha he wants to connect the ground of the 6VDC to the ground of the 12VDC.

I still don't see where thats a problem using the center tapped transformer and full wave bridge rectifier concept.
 
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I still don't see where thats a problem using the center tapped transformer and full wave bridge rectifier concept.
It makes +6v and -6V. Its 12V is the total of both without connecting to the grounded center-tap.
 
Naw:

I think this is what he wants:

Note the ripple as a function of the load currents.
 

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It makes +6v and -6V. Its 12V is the total of both without connecting to the grounded center-tap.

So what law of physics says you cant use the -6 volt point as the common ground and the center tap as the +6 and the top end as the +12? :confused:

The transformer doesn't care about what is used for what reference point and the circuit will still see a +6 and a +12 as it needs to.
 
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