Fully Discrete UCD with OVC and DC Protection


New member
Hello fellow switchmode fans :D
I recently made some Amplifier modules to use it in several Projects of mine...
Like the title says its UCD style, with dual power supply.

I studied Bruno Putzeys paper + the UM10155 application note from Philips
and developed my version of an discrete class d.
The biggest change was a simple buck with 2 Transistors to generate the 12V for the mosfet drive.
The pcb is only ~ 5 x 7 cm but with smd on both sides.
Used fets are: IPP147N12N3GXKSA
Inductors are t-106-2

Until now the only test i did, was drivng a 8 ohm PA sub with two modules bridged at +-48V at full power.
In idle 2 amps drain ca 6w.
Nothing overheated, but i will add a fan to keep the pcb cool.
The heatsink is really oversized, it didnt even get warm :D

The audio signal is managed by an ADAU1701.

Here some pictures:




Active member
Hello Plasma, It looks a very nice project and also compact and neatly done. I was just wondering if you made more tests with lower impedance on the output like 4 ohms or 2 ohms. You did not say what power you got into 8 ohms. Did you make any distortion test etc. Write your comments it will be very interesting to see how your amplifier performed.

Regards, Silvio


New member
i am sorry, but i didnt make more tests.
No overheat, no noise, no audible distortion, thats enough for me. :)
Mostly because my main goal was to make two pairs of a powered subwoofer+line speaker.
In the end i made them passive, and bought a TSA 4-1300. (didnt want my band to be dependent on diy electronics ^^)
But i made a new version of those UCD for smaller monitor speaker. (max +-30V)
They are now more compact and dont need a heatsink anymore.
I posted the monitor speaker in the diyaudio forum:
Later i replaced them with a TPA3116 ;)