200w/8Ω smps & class d module debugging

[authlxl]

I debugging new module for active speaker,200W/8Ω,500w/4Ω.I have upload first version PCB on diyaudio,
SMPS chip sg3525d,AMP use IRS2092 class d driver,OTP/OCP/DCP/UVP function inside,special function clip detect and protect.
now I adjust DT TIME for best sound out,low THD out.osc frequency set 500KHz-600KHz,high frequency for get high frequency response.
I found when signal near 15Khz,output signal become deformed，like triangular wave。anybody can tell me why.

[authlxl]

topic schematic here

[authlxl]

Module picture here.

[MOER]

Please post your full schematic with component values and then I can help

Steve

[darkfenriz]

What are LC components? The scheme looks strange to me (no DC feedback path??)

[authlxl]

Ok ,I have finished my works debuging,I finaly found my errors,I use three cermat cap in soc ,so bad performance,I found all OK when I change it with MKP series,now amp fequency reponse good value,10Hz-30KHz ±1dB.
If anyone like this topic,please send mail to me ,let's talk about it technology details.
Last night,I have to go to bed until 4:00AM,Switch amp design not easy but interesting.

[Baldin]

Hi authlxl

I'm a bit surprised that changing ceramic caps in the feedback path with NKT should do a big difference.
How big are these caps??

You have a feedback path from the output filter back to the input, without any compensation. How much feedback are you able to run this way?

Would love to see your schematics of the SMPS, I'm in need of an easy construction for a +- PSU for my new class-d design

PCBs look impressive.

How is the sound.
Did you get a clean 15 kHz??

Beat regards Baldin

[authlxl]

Yes,I only change CAP indeed,I add 1/10 negative feedback for amp in outside circuit.signal wave so good display on oscilloscope,I'll upload pic here later.I sync smps and class d for special circuit.smps use HALF BRIDGE voltage resonance..Normal circuit.

[Baldin]

Two questions:
No GND plane .... does this not create problems for your design??
Why the big heat sink ..... ??

[authlxl]

Ok,CHINA time 0:48am,I answer some question before I have to go to bed,my system designed for professional audio amp,no fan cooling ACTIVE SPEAKER SYSTEM,500W/4Ω $200w/8Ω,I make it works over 12 hours/100W/8Ω,when I touch heatsink only warm feeling.smps gnd/amp gnd/analog gnd are divided.
If you found another question ,please tell me .thanks!