TL494 D-Class module (Audio to PWM)

[CM800]

Hi All,
I was wondering if you guys would give a quick look at this, see if there is any obvious faults?





Also, is it possible you could put 5V on the output resistor rather then 12V, I wasn't sure if it should be going below VCC, but since my logic on the board this module would go to is 5V, I'd rather this be too.

I planned for this to output PWM @ 20kHz to drive small a little HV flyback transformer to give an HV arc output (Plasma Speaker)

[strawberry]

Between pin 2 & 3 need feedback resistor and pin 1 need 0V
5V is ok depends what MOSFET you have

[CM800]

Between pin 2 & 3 need feedback resistor and pin 1 need 0V
5V is ok depends what MOSFET you have

here is the original circuit I was working off



I'm forgoing the feedback in this case.

It may work, but the audio quality may as well be horrible. I suggest some higher performance modulator designed specifically for hifi class D applications, such as these IR digital amp ASICs or TI ones (even come with power stage or a real gate driver that can drive massive MOSFETs).

I agree and somewhat expect that, though to be honest it's going into a transformer and the audio will come from the arc expanding and contracting, like so:


I couldn't find any good modulators without the power stage. (I want to be able to put mains DC in)

[diyaudio]

Hi All,
I was wondering if you guys would give a quick look at this, see if there is any obvious faults?





Also, is it possible you could put 5V on the output resistor rather then 12V, I wasn't sure if it should be going below VCC, but since my logic on the board this module would go to is 5V, I'd rather this be too.

I planned for this to output PWM @ 20kHz to drive small a little HV flyback transformer to give an HV arc output (Plasma Speaker)

This has been discussed over at diyaudio,
http://www.diyaudio.com/forums/class-d/148287-doing-class-d-amp-project-using-tl494.html

TL494 is a bad choice, for example it uses sawtooth instead of a triangle wave. A simple class D amplifier with quite good performance can be built around just a fast comparator. Do some research on the UcD concept. It's a phase shift oscillator that amplifies audio and damps output filter resonance to flat response regardless of speaker impedance in the process...