UCD 25 watts to 1200 watts using 2 mosfets

hi lycanic
greetings today i assembled the 12 volt regulator circuit on bread board tip 31 12 volts 1 watt zener 4.7 k 1 watt resistor 47 uf condenser and on
measuring voltage on emitter got 11.8 volts positive probe on emitter negative
probe on negative rail but in the circuit the emitter voltage is 26 volts does not look ok checked everything any reason why amp is not working can you tell
some voltage test points so i can recheck again.THIS amp has given most
trouble in all the amps i have assembled so far hoping you can help out.

thanking you
andrew lebon
 
hi lycanic
greetings today i assembled the 12 volt regulator circuit on bread board tip 31 12 volts 1 watt zener 4.7 k 1 watt resistor 47 uf condenser and on
measuring voltage on emitter got 11.8 volts positive probe on emitter negative
probe on negative rail but in the circuit the emitter voltage is 26 volts does not look ok checked everything any reason why amp is not working can you tell
some voltage test points so i can recheck again.THIS amp has given most
trouble in all the amps i have assembled so far hoping you can help out.

thanking you
andrew lebon

Can you send us a clear pictures of your assembled amp.. I can assure that the PCB is fully functioning.. 12v regulation is ok in your case..(in your test board) Did you check the zener voltage on LM311 in both rails ? Author has given a very descriptive post on their thread. you can refer that too.. I can't remember the post number.. just check first 10 pages of their forum..

12v regulation is ok in your test board that will give you 12v (11.8 is ok) but not in the circuit !
as Baldin has mentioned tip31 has gone already or may be the 12v zenner.. If so .. perhaps your IR2110 is gone too sadly.. but not sure...first correct the regulation on amp! then only try changing the chip. !

regards,
Lycanlk
 
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I could reduce 100% noise, I guess because I cant hear any :) simply the amp wont generate noise.. It was my bad that I didn't measure the inductance.. (I didn't have a tool to measure) only followed theory.. but the real values are different. I did so many experiments with the amp. It doesn't even need a ground plane to work well !!! neither a dual layer PCB.. All you need to worry is to have a good inductor !

Still my inductor warms up due to low no of turns.. The coil heats up not the core! but its natural. i cant change no of turns caz it will affect to the inductance again. I can only try with a large core.

each and every ferrite has a working frequency.. if you go beyond that it will heat up! According to the author this amp works at 250Khz so if you select a toroid core at that frequencies, to achieve 30-40 uh you may only need 1 or 2 turns.. The amp will work well but the coil might burn in few seconds.. hahahaha.. so eventually you need to increase the no of turns.. but it will rise the inductance again.. Then the other option is select a toroid work on low frequencies.. then again the core will heat up ! This is so funny.. but its the nature where I could think out of the box !

I never give up on things easily.. So I do more and more experiments.. I found that I part of an E-Core gives a better result.. about 30 turns works well and less heat.. then I wound it on my broken toroid ..again 30 turns and 44uH.. amp works fine heating slightly.. I think about 70-80 Celsius..

I think ferrite sticks are the best solution!.. air coil is also good but it will be large and high resistance. Use common sense and do experiments and wind your own coil about 30-40uH. Amp will work well ! Its a nice design.. very simple and amazing sound.. many thanks to Ejtagle once again! and also Andrewlebon for starting this thread !

keep in mind more heat will change the inductance of the coil.. and it will start noising again due to change in uH value !

consider that low gage wire has skin effect on high frequency !
American Wire Gauge table and AWG Electrical Current Load Limits with skin depth frequencies

I should remind my friend Carlos.. Destroyer X was My first class AB Amp where I learnt a lot from his thread :) now I learnt a lot about UCD by experiments, not with designing UCDs but its behavior at least..

Enjoy the amp!

regards,
Lycanlk

Hello lycanlk!

Can you share power board for UCD? ( schematic and PCB).

Thank you!
 
It is not fake.
I have made an (I think improved version) I got it up and running at 200 kHz at +- 30V, music through ok (but it is somewhat different from the posted circuit ... see my previous post).
But I also have problems making it oscillate. This is not something new for me, I have made more designs with IR2110 whic also are difficult to get to start. I normally handle this bu making an inner fb loop, from before IR2110 and back to either the comparator or the integrator, depending on design.

As Eva posted on one of the first pages, there is many variables in the circuit which depends on the components and it would probably be that some worked and sone didn't

Do you have a load on when switching on? ... I think this is necessary in most cases with this circuit.
Try to switch on and of a number of times with only 1 second of on/off ... this sometimes help me getting it started. (this is of course not a lasting solution though :))

Keep it up ... get it to work ;)
 
Works but ....

Ok. Changed a few components, and skipped the big capacitor in the input ...

Now it starts up every time, but only with a load (speaker or 8 ohm resistor).
Switching freq is 235 kHz

Because I had to remove the big cap ther is 0,6 V DC on the output .... need to find a solution ... any suggestions??

Also need ot find a way to make it start without the load ...

Otherwise it seems quite good for a breadboard circuit ;)

And I think it is an improvement over the original ........
 

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It started no prollem with or without load but its unfortunately dead again, a loose strand on the +15V feed wire to the IR2010 touched a transistor leg with caused severe farting and banging from the speaker, then it was dead.:(

I now fear that pretty much every semiconductor on the board is dead so i figure its easier to just make a new board and start over.:dead:

Oh well **** happens i guess.

Btw my switching frequency was around 7µS which is around what, 50-100kHz ?
 
Also need ot find a way to make it start without the load ...

The problem with the startup in selfoscillating class d amp usually is that it MUST start with the negative impulse at the output, to let the bootstrap capacitor charge (I mean the bootstrap capacitor of the mosfet driver). If this condition is not met (if the comparator waits for INITIAL positive impulse at the output), then the bootstrap capacitor is not charged yet, and it is not possible to open the high side mosfet and it is not possible to generate any positive voltage at the amp output. So the amp simply will not start to oscillate...

To solve this problem, it is usually enough to connect amp output to the positive voltage rail using 50K-100K resistor. This will generate small positive voltage offset at the amp output after power is on, and the input comparator will initiate the negative cycle first, which will charge driver's bootstrap capacitor effectively...