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Power amplifier

Mads

Apr 11, 2013
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Hi forum

I have a 0-5v (DC) signal with properly only around a few mA. And I want to transform that to 0-12v with 10-15Amp. Is that easy? and what is the name of the device that can do that?

I have seached the web for the last two hours and I cant find anything that can help me.

Thank you! :-D
 

duke37

Jan 9, 2011
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You cannot transform a low power signal to a high power.

Do you mean that you wish to control a high power supply to give an output of up to 12v at up to 15A/

What will be your supply?
 

Mads

Apr 11, 2013
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@duke37

yeah that I exactly what I want. A power supply where the output is controlled based on my control signal. Does such a device have a specific name?
 

(*steve*)

¡sǝpodᴉʇuɐ ǝɥʇ ɹɐǝɥd
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Jan 21, 2010
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The device is a MOSFET.

However there's more to it than just connecting it up.

It may be better to use a transistor and a relay for example.

We need to know more:

1) Do the signals have a common ground?

2) what voltage drop across the switching element is tolerable?

3) how often (times per second, per minute, or per day) will it be switched?

4) what is the load (we need to know if it is undefined, or if it may be capacitive or inductive.

5) what does your 5v signal look like (square wave? rise and fall times?)
 
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BobK

Jan 5, 2010
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In addition to what Steve asked,

Is the signal either 0V or 5V (digital) or anywhere within that range (analog)?

Bob
 

Mads

Apr 11, 2013
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@BobK
My signal is a analog 1-5V signal (and not 0-5V as I said before).

@(*steve*)
I think I mislead you into thinking that my signal was digital when it is actually analog

I'll try to draw what I mean:

if inputsignal = 1V, then output = 2.4V (High current, +10amp)
if inputsignal = 3V, then output = 7.2V (High current, +10amp)
if inputsignal = 5V, then output = 12V (High current, +10amp)


can this be made?
 

BobK

Jan 5, 2010
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Basically, you need a high power opamp.

They exist, but they aren't cheap.

High Power Op Amps at DigiKey

Alternatively, you could try to make it yourself, using a normal power opamp and a push-pull power darlington output stage.

Bob
 

BobK

Jan 5, 2010
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On second thought, you need to answer Steve's questions as well. If the signal only changes slowly, perhaps a voltage controlled power supply is the answer, and if it changes too rapidly (1MHz or higher) even an opamp solution will be very tricky.

Bob
 

Mads

Apr 11, 2013
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BobK

Thank you for your answer - I'll be googling high power opamp.

It changes really slow so that shouldn't be a problem
 

BobK

Jan 5, 2010
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So another, much cheaper, option is to build a regulated power supply and use the 1-5V signal as the reference.

Here is a supply design that would be suitable:

http://ludens.cl/Electron/Ps20/Ps20.html

You would just take out the zener based reference that goes to the - input of the op amp and replace it with your 1-5V signal and adjust the pot to get 12V out with 5V in.

Bob
 
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