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Give me a 5w or 10w amplifier circuit

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abdulmakhdoom

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post the 3w or 5w or 10w amplifier circuit from 5v source.
 

BradtheRad

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Is your load a typical 4 ohm speaker?

Then with a 5V single polarity supply...
you can use a full H-bridge to get 3W, by careful adjustments to optimize performance.

Or, if the supply is bipolar +5 -5 V...
then a class AB can easily yield 3W output.
 

rohitkhanna

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post the 3w or 5w or 10w amplifier circuit from 5v source.
imo a power source of only 5v implies that your pk-pk voltage swing is max 5v.
This implies a Vrms of just 1.768v

Hence to derive even 3W, we need a load (spkr) impedance of < 1.768^2 / 3 = ~1 ohm !!

Or am i missing something ?
 

abdulmakhdoom

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If 3w is not possible for +5v source then please give me the info of 1 or 2w amplifier circuit with +5V source.
 

BradtheRad

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This is a very simple H-bridge audio amplifier.



With a 5V supply, it can deliver over 9V peak-to-peak (if the incoming waveform has sufficient amplitude).

It wastes over 300 mA when there is no signal. It will take some additional circuitry to remedy this.
 

goldsmith

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Hi
I've designed this circuit for handling out put power , of 20Watts ( something around it ! ) . take a look here , please :


It's input also can be a microphone ! or everything that you're interested in ! for changing the out put voice amplitude you can easily add a potentiometer in your input or perhaps instead of gain control resistors .
Best Wishes
Goldsmith
 

rohitkhanna

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This is a very simple H-bridge audio amplifier.

With a 5V supply, it can deliver over 9V peak-to-peak (if the incoming waveform has sufficient amplitude).

It wastes over 300 mA when there is no signal. It will take some additional circuitry to remedy this.
Ah yes - good one Brad. I forgot about the voltage doubling effect of the H-bridge config. This would give around 2.5Wrms into 4ohm spkrs/ 5w into 2ohms, with some improvements in the biasing arrangement.

How about a class-D config driving a H-bridge - for better efficiency ?

- - - Updated - - -

Hi
I've designed this circuit for handling out put power , of 20Watts ( something around it ! ) .......
This doesn't work off +5v... its using a +/- 15v power source !!
 
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BradtheRad

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Originally Posted by rohitkhanna
...
How about a class-D config driving a H-bridge - for better efficiency ?
Yes, class D consists of pulses that go from supply rail to supply rail.
It will be able to get the most out of the 5V supply.
If it is done with an H-bridge, it could make use of the entire 10V.

It so happens that Goldsmith is able to help with information about class D amplifiers.
 

goldsmith

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This doesn't work off +5v... its using a +/- 15v power source !!
Hi rohitkhanna
Why you think the circuit should work with 5 volts ? what is the benefit of a 5 volts supply ? . the original poster didn't mention the supply rating before .
And another point is you can decrease supply voltage of my circuit too ! so that's not a problem .
How about a class-D config driving a H-bridge - for better efficiency ?
A question , why for such a low power , rating we should design a class D amplifier ? that's not economic for 10 watts !
However it has pretty low THD and much better efficiency but i think price is important !
By the way , the circuit that has been presented by Bradtherad is a good idea too . ( for this range of power his circuit or my circuit in my former post are both fine )
Regards
Goldsmith
 

rohitkhanna

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Hi rohitkhanna
Why you think the circuit should work with 5 volts ? what is the benefit of a 5 volts supply ? . the original poster didn't mention the supply rating before .
Read post#1 again please.

And another point is you can decrease supply voltage of my circuit too ! so that's not a problem .
Your circuit uses TL072 which are not rated for supply voltages below 7v, so it will not work with 5v. Secondly, even if you found opamps to work at sub-5v supply, your biasing scheme for output bjt's will need modifications. Lastly, your design works using split supply - while we are discussing single supply options.

A question , why for such a low power , rating we should design a class D amplifier ? that's not economic for 10 watts !
However it has pretty low THD and much better efficiency but i think price is important !
Because the OP asked for +5v supply & 3/5/10 watts operation.
 

goldsmith

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Hi again
Read post#1 again please.
Yes you're absolutely right . i didn't see the end of his sentence and it is very fun ! ha ha !
Your circuit uses TL072 which are not rated for supply voltages below 7v, so it will not work with 5v. Secondly, even if you found opamps to work at sub-5v supply, your biasing scheme for output bjt's will need modifications. Lastly, your design works using split supply - while we are discussing single supply options.
Again You're quite right . but it is not a problem ! because he/she can use a push pull amplifier to increase the out put voltage with taking more current ! so main supply can be 5 volts but out put voltage can be higher !
Because the OP asked for +5v supply & 3/5/10 watts operation.
I hope you know about limitations of a Class D amplifier . there are gang of reasons that why a class D amplifier isn't good choice with 5 volts supply !
Regards
Goldsmith
 

rohitkhanna

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.....use a push pull amplifier to increase the out put voltage with taking more current ! so main supply can be 5 volts but out put voltage can be higher ! ...
This is precisely what Brad & myself were advising when we wrote about the H-bridge config. Note that the output voltage is NOT 'higher', just that at the speaker terminals the voltage gets inverted, and hence 'appears' to be double.

I hope you know about limitations of a Class D amplifier . there are gang of reasons that why a class D amplifier isn't good choice with 5 volts supply !
please enlighten us ? Other than design of LC filter matched to the speaker - which is of course critical - what are the other issues? I would think that at such low voltages, with proper use of selected MOSFETS, the class-D would probably be the most cost efficient in terms of Audio-Watts/ Cost/ Power consumed.

In fact, here's a chip which does exactly this -- http://www.onsemi.com/pub_link/Collateral/NCP2824-D.PDF
 
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goldsmith

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Note that the output voltage is NOT 'higher'
Hi again
May i ask you what you mean by that ? as i can remember i've noticed about a Push Pull amplifier with transformer which can easily increase the voltage with taking more current . i think you've misunderstood my meaning ?

please enlighten us ? Other than design of LC filter matched to the speaker - which is of course critical - what are the other issues? I would think that at such low voltages, with proper use of selected MOSFETS, the class-D would probably be the most cost efficient in terms of Audio-Watts/ Cost/ Power consumed.
And about this issue . i hope you know a class D amplifier needs more attention and experience while designing the PCB . because of the high frequency components of current . and as it appears author of this thread is a newbie in electronics . hence he/ she won't be able to design it's PCB .
You simply noticed about a class D amplifier . but it needs gang of experiences . in driving mosfets with proper method . creating enough dead time for mosfets . out put filter is pretty important . it's impedance should be normalized for the load impedance as well . creating a good SPWM signal requires enough experience . winding the inductor for a best class D amplifier requires more experience too . it's DC supply should have good features too . these are for an open loop class D amplifier ! a closed loop class D amplifier is so complicated for a newbie . and another thing is amplitude of your audio signal should be nearby amplitude of triangular wave . so a voltage amplifier is required . so what circuit should be sued for a voltage amplifier before comparator of SPWM ? some op amps ? transistors ? if so , would be just 5 volts sufficient for them ? i hope you know a comparator to deliver a good SPWM needs simultaneous supply ( +- VDC ) so that's not a good idea with these demonstrations to use a class D amplifier for this case .
Best Wishes
Goldsmith

- - - Updated - - -

By the way the IC that you've introduced is designed to prepare 2.4 watts across the 4 ohms load !
and how about it's input signal ? it should be at maximum amplitude to deliver 2.4 watts .
although 2.4 watts isn't required by the original poster . he / she needs 5/10 watts .
So that's not a good idea too .
 

abdulmakhdoom

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I need a simple npn or pnp transisor based amplifier having load or output is 4ohm (1 or 3 or 5w) with +5v supply.........
 

BradtheRad

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At 5V single supply, a one-transistor amplifier won't give more than a couple tenths of a watt. That would be a class A type.

The next step up is a class AB.

Because I'm a nice guy...

and because I can't hope to make a million dollars from this design by marketing it myself...

I'll post the schematic.



Average power is around 1 watt.

The incoming waveform must have sufficient amplitude.
 

goldsmith

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without transformer......
Hi again
That's impossible to achieve this power rating with 5 volt supply and a 4 ohm load without transformer !

Good Luck
Goldsmith
 

rohitkhanna

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Hi again
That's impossible to achieve this power rating with 5 volt supply and a 4 ohm load without transformer !

Good Luck
Goldsmith
Yes goldsmith... we have already established that in this thread.
He is now asking for 1w/3w/5w... And we also pointed the way to achieve upto 2.5w max.
 

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