UcD like topology amp.

[acid_k2]

Whortless, really nice work.
Now I'll try to obtain the IRS20954 from my local electronics shop... hard job

[Whortless]

Hi,
Thanks and good luck. Will you use compementary output comparators like mine?(LT1016,LM361,TL3016 LT1116, MAX913,MXL1016 etc.). Please use good mosfets like IRF540Z, IRFB5615,5620 and similar like these. I also advise you to use add passive poles into your amp. If it would not better philips won't use the circuit in their home appliance( FM730). I enclosed shematic for non SWCAD users.

Regards

[Cro maniac]

Nice design Whortless !

Do you have some measurements of THD of your amp ? That 2nd passive pole looks interesting ,every UcD paper I had read mentions it but I never saw one diyer implementing it. I wonder how much can one expect the THD to decrease when adding the second pole to the FB.
At the moment I'm in a process of designing a half bridge amp with irs20957 and that's how I bumped to this wonderful thread.
I see that you have set overcurrent limit very high. Was there a problem with false triggering of ocp ? For low side it is set at 50A and for high side 38A if I calculated it correctly, and I see from the datasheet that those Philips mosfets can "only" take max 22A @25°C.
Are you using balanced input to your amp ? The feedback configuration suggests you are, otherwise, I think it could be made simpler if using only single ended input.
Do you have emi problems ? I see the toroid is mounted vertically and you have the connections on both sides of the PCB.
The board looks very well made. My boards containing smd elements usually don't look nearly half as good as yours . Nice work !

[Whortless]

Originally Posted by Cro maniac

Nice design Whortless !

Many thanks! And sorry for the delayed answer.

Originally Posted by Cro maniac

Do you have some measurements of THD of your amp ? That 2nd passive pole looks interesting ,every UcD paper I had read mentions it but I never saw one diyer implementing it. I wonder how much can one expect the THD to decrease when adding the second pole to the FB.

Un fortunately I do not have chance to measure distorsion values yet. But, one of my friend really like its tonal quality.

Originally Posted by Cro maniac

At the moment I'm in a process of designing a half bridge amp with irs20957 and that's how I bumped to this wonderful thread.
I see that you have set overcurrent limit very high. Was there a problem with false triggering of ocp ? For low side it is set at 50A and for high side 38A if I calculated it correctly, and I see from the datasheet that those Philips mosfets can "only" take max 22A @25°C.

I set OCP limits high for test purpose because my PS has OCP protection. Also the mosfets that I have used has 35S forward transconductance so, they can suffer from some short circuit or inproper timing events for a while. But, I would really suggest to use IRS20957 instead of 20954 for this purpose because 20954 has not matched internal protection circuits.

Originally Posted by Cro maniac

Are you using balanced input to your amp ? The feedback configuration suggests you are, otherwise, I think it could be made simpler if using only single ended input.

I did not decide the balanced or unbalanced input yet. But this desing can let both application. If you are asking about not using the 2nd pole components on unused input. I can say I did not test that configuration. But, this can make some offset on output.

Originally Posted by Cro maniac

Do you have emi problems ? I see the toroid is mounted vertically and you have the connections on both sides of the PCB.
The board looks very well made. My boards containing smd elements usually don't look nearly half as good as yours . Nice work !

I do not have EMI problem, my FM radio can drive the amp (single ended) and also can work near to amp while the amp driven by computer. But, if I connect the ground pin of my scope to center of output mosfets to measure the high side gate timig my LAB PS's LCD shows some silly values . I think it is normal because the probe cable became a very good antenna for the amp. The output filter do not have connetction on both side. It has connections only on component side of PCB. I do not have much experience of desining a good PCB and I usually do not consider some "musts" while drawing it. But, at the end I usually like my desings and up to now i did not faced some interference problems or something like this. Futhermore, I desinged a bit complicated version of the amp and I think you do not want to see it.

Best regards and good luck on your desing.

[Bender.ru]

Hi Whortless! Nice project, my congratulations :-).

[Whortless]

Originally Posted by Bender.ru

Hi Whortless! Nice project, my congratulations :-).

Dear Bender,

Please excuse me because of posting some improvements in your thread like mine. I think you can try passive pole version and can post the distorsion measurements for DIYers. I do not have much time to do these issiues and also have to barrow some instruments from my friends. Anyways, again many thanks and my congratulations about the idea.

Best Regards

[savu]

Originally Posted by Whortless

Dear Bender and all,

I realised that Bender and the others are not interested with the above questions. Anyway! Therefore I tried to make my own desing and get the smallest amp below. Bender, please excuse me if I get you bother by posting in your thread.

First of all simulate the shematic. I used the chip IRS20954S which is known as unsable( Make a diyaudio search) and old IC. I get it from Farnell, it is cheap for now. I did not faced a problem by implementing it. My output mosfets are IRFB5615PBF. SW frequency is 550-600kHz. Input comparator is MXL1016 from Maxim and sound is very good just for my firts testing. DT adj is max(45ns) for first test purpose. I think I have to decrase the sw frequency down to 400k and set the dead time into a suitible time(25ns?).

Regards

NB. If someone interested I can give the PCB toner file

Hello Worthless ...
I am a bit curious about the pcb ... looks very tight.
I am triyng to make my own pcb's but have problems with understanding the layout for class D because i'm new in class D. But i will learn a lot from youre schematic and PCB.

Thanks a million.

Savu Silviu

[MOER]

I have many in stock. Price is $3.25 + shipping.

[savu]

Originally Posted by MOER

I have many in stock. Price is $3.25 + shipping.

I live in Romania and shippment is 50$, and I want to make my own PCB because I want to learn.
I just wanted to look at the design to see the gate traces, the ground planes and so on ...

Best regards,

Savu Silviu

[savu]

Originally Posted by Whortless

First of all simulate the shematic.

Hello Wortless,
Do you have the LTSpice model for IRS2095?

Best regards,
Savu Silviu