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1w Class D Amplifier

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feyzul31

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i am searching circuit design of 1w class d amplifier, i have no enough knowledge about electronics or circuit designing, please help.
also i have searched whole network about class-d via google, but i could not find any sufficient documents.

i know 1w is a simple value if we think more powerful amplifiers, but this is my homework, i have basic block diagram as you saw. but i could not know how to design and define the values of electronic materials.
 

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1W into an 8 ohm speaker is a signal of 2.83V RMS which is only 6.5V peak-to-peak.

The comparator has a triangle-wave input and the signal input and is a high frequency Pulse-Width-Modulation circuit.

The LC network feeding the speaker is a lowpass filter.

I remember seeing your block diagram in Google. I think its article explained how it works.

Now learn about comparators, Mosfets, PWM circuits and lowpass filters then make a class-D amplifier.
 
i have researched whole the net to find a schema but i couldnt find. Afterthat, i have designed a circuit (attached). But i have some errors i think, because it didnt work properly. please help. i have to find a 1w d class circuit. very important.
 

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Nice try.
But the old LM324 opamp is way too slow. I recommend using a TLC071 modern opamp that is 100 times faster.
The transistor isn't needed then the supply voltage is too high for the gates of the Mosfet. A total supply voltage of only 12V is plenty.
I re-calculated the LC filter for a cutoff frequency above the audio band.
I used an 8 ohm speaker because an 8k ohm speaker wouldn't make much sound.
It should have an output power of about 1.8W.
 

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thanks guru, i want to simulate this circuit not only theorically but also practically, so i looked for irf9140 p channel mosfet, or irf 150 n channel mosfet, but i couldnt find them. which fets could be used for them? same problem with opamp. what are your advices?
 
There are hundreds of Mosfets that will work in that amplifier circuit. There are also quite a few wideband opamps but that is the one I use and I don't know anything about what you can or cannot get in Istanbul.
 
Well there's a LOT of electronics manufacturing going on in Turkey, all the cheap junk TV's in Europe are made there, apparently the EU give Turkey huge grants?.
 
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