Class D Amp

[culteousness1]

Hi Team,

just wanted to share a prototype with you:

Basically it's a 2x 50 W Class D Amp based on a TI TPA3116 with additional power
filtering and some EMI protection. It's got options for differential or SE inputs.

This was my first Class D design and I have to admit that I am very pleased by the
outcome. Chapeau to Rochey and his colleagues!

Best,
Carsten

[EDIT: FIXED LINKS.]

 

[mjrippe]

Beautiful symmetry in the layout!  Though for some reason it is frightening to me that the largest component in a 50w amp is a capacitor...

 

[culteousness1]

That's true. The TPA3116 is really tiny 

During the first tests the heatsink had around 65°C.
So maybe the heatsink will soon be the largest part in the layout  ;D

 

[JohnRoberts]

I recall throwing together a small (couple watt) class D amp on my work bench back in the early 70s using a fast (for then) LM311 comparator and random parts. 

I knocked out radio reception for the entire building.  After proving that I could make sound I took it apart. Class D wasn't ready for prime time yet...

IIRC back then ('70s)Sony developed a class D consumer audio amp, then pulled it off the market almost immediately because of  RF emissions concerns.

JR

 

[culteousness1]

IIRC back then ('70s)Sony developed a class D consumer audio amp, then pulled it off the market almost immediately because of  RF emissions concerns.

Haven't noticed any bad things yet. Maybe I will take the board to our EMI chamber when I am back at work.
But I doubt there will be any significant emission. Switching frequency is set to 600 kHz and I opted for a larger
output filter.

What is really cool is the wide supply range. I tested it fine from 5 V up to 21 V.
Though I had some thermal issue at higher supply voltages  :

Carsten

 

[JohnRoberts]

Yup output filters and PS caps should keep the EMI low. If you are going to test it maybe hang a speaker wire on it while testing.


JR 

 

[culteousness1]

Received the final boards some weeks ago. They have the heat sink attached on the
bottom side to the thermal pad of the IC. A standard LED head sink is used.

The last photo shows a test I set up. The whole system is powered by a small USB power
bank and runs for two hours up to now 

So the amp is suitable for mobile applications as well.

Best,
Carsten

[EDIT: FIXED LINKS.]

 

[Rochey]

Glad you like the 3116!

You need  to check out the latest tpa3251d2. We released it a few weeks ago.

It's amazing - lots of work done to improve the noise floor.

Cheers

/R

 

[culteousness1]

After one and a half year, I finally found the time and money to put the amp into a shiny box 

Now I only need to measure the EMI as promised to John  :

Cheers
Carsten

 

[JohnRoberts]

Nice...

I keep waiting for the dollar to get stronger vs the euro so I can buy 6 channels of Bruno Putzeys class D amp modules (I'm cheap and patient).

JR