Here the situation: I have all mi pieces wired up fine and working, my project drives an RGBW LED, high power (e.g. Luxeon or similar) using a NPN transistor wired in the classical way. This LED ha to work on the same circuit of a "wave shield" I have optimized and miniaturized that with a custom SD reader, an MCP4921 and a TDA7052 amplifier wired in the classical way reported also on the datasheet for 1W amplifier like so: http://www.afiata.com/tda7052-datasheet-and-circuit-audio-diagram/
Now the problem: sending PWM signal under 255 values makes the Speaker catch some noise from the PWM signal. I tried filtering the Amplifier but did note work, plus I had a loss of volume. I would like to avoid this solution, what I am seeking is how to filter the positive side of the wired LED (or add something on the transistor) to get rid of the interference. At the moment I can lower the sound putting an electrolitic capacitor of 470μF from positive THE to the negative battery. But it is not enough to turn off the sound. Puting higher values does not makes the trick, I already tried. What I need is a filter that takes the square waves of the PWM exiting from the LED and take them to a flat level that does not make interference with the speaker.
How is that possible?
I put a picture of the partial schematic if you need more specific ones I will have to provide it later. Tahnks for any help or hint you can give me!