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Help with Class D amplifier

gibon0695

Dec 2, 2015
27
Joined
Dec 2, 2015
Messages
27
Hey guys, I'm trying to build this circuit:

MITAXQ5_zpsqgkzxjw1.jpg


I've got it hooked up to a 24V power supply.

It does not seem to be working properly. My issue is that the sound outputed by the speakers is very quiet, it's a very clear sound, just quiet. I cannot seem to find out why. The speakers are 10W RMS and the output from the chip at 24V (0.5A per channel) is around 8W. So it should be working fine. Input is from my 3.5mm jack connected to an iPod.

Can anyone suggest a possible reason for this issue? I've checked the connection multiple times... either I'm doing something wrong or there is a bigger issue.

Here are some images of my circuit (currently only testing on breadboard).

image.jpg


2_zpsysprvxfx.jpg

3_zpsmuxycvg3.jpg


Thanks Guys
 

AnalogKid

Jun 10, 2015
2,884
Joined
Jun 10, 2015
Messages
2,884
What are the peak to peak input audio voltage and the peak to peak audio voltage across the speaker? Voltmeters lie; trust a scope.

ak
 

Alec_t

Jul 7, 2015
3,587
Joined
Jul 7, 2015
Messages
3,587
What voltage do you have on pins 14 and 15?
 

gibon0695

Dec 2, 2015
27
Joined
Dec 2, 2015
Messages
27
What voltage do you have on pins 14 and 15?

I've got pin 14 at 0V and pin 15 at 24V, This produces a gain of 20dB according to the datasheet which is more than enough for what I need. I have also tried both pins at 24V (63dB) and the output is exactly the same (very quiet).
 
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