Class D amp using TL494

[stepheno]

Hello Ledmania,
Are you still around?
Just to let you know and make you glad: I have taken your half-bridge topology as suggested in your very first post (not really new to me and not new to the Japanese as you yourself witnessed - also not new to anyone designing power converters). I then took the IR reference design and combined the two into a Sigma-Delta UCD. The IR circuit is vastly simplified and improved.
Sincerely,
Stephen

[ledmania]

Hi stepeno! Yes, I'm still around but not as frequent as I'm in Manila because I'm back again here on board the ship.
I'm glad that you resurected my long burried thread and I,m trying to imagine what sigma delta modulation you applied on it
Care for a schemo?

regards ledmania

[Tekko]

Post schems and pics, others may want to see.

[stepheno]

Hello Ledmania,
Interesting of you being on ships!
Tekko,
Unfortunately I am not providing a circuit.
I can but say that when compared to the IR design, it is so simplified that no level shifter and no negative voltages are required.
Sincerely,
Stephen.

[eltonseemann]

I implement ledmania concepts for tl494 based pwm but I use the IR mosfet driver IR21844 that simplifies a lot the work. No overcurrent nor external deadtime has aditioned (the IR driver introduct programed deadtime).
I found problems when more volume is used. The sound is distorced at peaks. Any sogestion for correct this?? What possibles causes? Any associated to mosfet driver at longer duty cycles?
I work at aprox. 120Khz (tried lower too)
+-56V source, commom mode voltage at error amp of tl494 = 3,6V (the app report from texas pag.8 afirm that work which commom-mode voltage range from -03V to 2V less than Vi)

[eltonseemann]

layout

[eltonseemann]

layout

[altium]

Hi Ledmania,
I cannot open your schematic from this chapter: Class D amp using TL494

Can you upload him correctly, please?

[Pafi]

Originally Posted by eltonseemann

I implement ledmania concepts for tl494 based pwm but I use the IR mosfet driver IR21844 that simplifies a lot the work. No overcurrent nor external deadtime has aditioned (the IR driver introduct programed deadtime).
I found problems when more volume is used. The sound is distorced at peaks. Any sogestion for correct this?? What possibles causes? Any associated to mosfet driver at longer duty cycles?
I work at aprox. 120Khz (tried lower too)
+-56V source, commom mode voltage at error amp of tl494 = 3,6V (the app report from texas pag.8 afirm that work which commom-mode voltage range from -03V to 2V less than Vi)

I don't know what is the reason for your distortion, but this schematic looks horrible (no junction points, hardly readable characters), and basically the feedback is designed not at all. OPA without feedback: bad idea. IR21844 has too much dead time. (400 ns is too much.)