Dzony988 ..you shoud have no bus pumping in bridge mode.
Unfortunately No One makes real tests..i asked several times for some distorsions tests in vain...
Also i am interesested how you have implemented your protection schemes..the amplifier has to survire a short to output or rails, also over power in hard clipping,excesive bus pumping at 10-20hz and very high currents(>20A) ...simply sensing peak currents is not enough.
Unfortunately No One makes real tests..i asked several times for some distorsions tests in vain...
Also i am interesested how you have implemented your protection schemes..the amplifier has to survire a short to output or rails, also over power in hard clipping,excesive bus pumping at 10-20hz and very high currents(>20A) ...simply sensing peak currents is not enough.
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Alot can be done..and i am still doing experiments.
I have around 10-15 volts bus pumping at 20 hz so probably this in not the reason my fets burn at 25A,but reducing capacitance from 10mF to 5 mf makes them burn at only 8A rms,so bus pumping may not be the problem...increasing capacitance to 15mf and adding a high pass filter will probaly solve this...
Hard clipping is another story..when hard clipped before peak current the peak current protecion will not work since is not measuring rms.A rms to voltage should be used but the conversion is to slow for efective protection so i will try implement an aditional rms current protection.
Also a clipping current limitator can be implemented but that will not save the amplifier if it is fed with a square wave.
I have around 10-15 volts bus pumping at 20 hz so probably this in not the reason my fets burn at 25A,but reducing capacitance from 10mF to 5 mf makes them burn at only 8A rms,so bus pumping may not be the problem...increasing capacitance to 15mf and adding a high pass filter will probaly solve this...
Hard clipping is another story..when hard clipped before peak current the peak current protecion will not work since is not measuring rms.A rms to voltage should be used but the conversion is to slow for efective protection so i will try implement an aditional rms current protection.
Also a clipping current limitator can be implemented but that will not save the amplifier if it is fed with a square wave.
You mean pumping ?
In full bridge there"s no bus pumping
It may be if the bridge is unbalanced by using different switching frequencies between amplifiers creating unequal gain,but should be negligible .. 1 or 2 volts.
In mixed mode operation(stereo - bridge) you need to have different switching speeds and gains.CPX
Agree with you.
But that"s not a good bridge
And i doubt about switching freq.
BAFFLED
Hi
greetings can any explain my problem i have assembled egtagle orignal ucd amp on his orignal pcb i have no issues with amp its working well strong output
supply is 36 volts ac transformer dc rails are approx 50 volts dc on supply rails are 1uf 2 caps on each rail then i designed pcb for sameerx1 only thing i added was .1 and 470uf on each rail and same 1uf 2 caps on each rail AMP playing ok
on 24 volt ac trafo but as i switch to 36 volt ac trafo amp blows within seconds
can any one tell me whats the reason its very important for me to know the reason so i can progress further in DCLASS
warm regards
andrew lebon
Hi
greetings can any explain my problem i have assembled egtagle orignal ucd amp on his orignal pcb i have no issues with amp its working well strong output
supply is 36 volts ac transformer dc rails are approx 50 volts dc on supply rails are 1uf 2 caps on each rail then i designed pcb for sameerx1 only thing i added was .1 and 470uf on each rail and same 1uf 2 caps on each rail AMP playing ok
on 24 volt ac trafo but as i switch to 36 volt ac trafo amp blows within seconds
can any one tell me whats the reason its very important for me to know the reason so i can progress further in DCLASS
warm regards
andrew lebon
Both mosfet u post is NO. Not suiteable and too much Rds-on and others etc etc.. Dont try it with that mosfet. bad idea
THANK YOU FOR REPLYING
Hi Norazmi
greetings thanks for your helpful replies d class very new to me
1 MOSFETS irf250n with gate resistors 27 ohms just finished testing egtagles
orignal pcb with 55 volts dc rails working good i think 60 volts dc is max limit
for IRFP250N using mje13007 instead of TIP 41 resistor 6.8k 1 watt getting about 11.8 volts dc on emitter of mje now on new PCB on supply rails i only added 470 uf 100 volts and .1 cap in addition to the 2 1uf 100volt caps on each rail components DAMAGED
12 IR2110 gone GATE DIODES BLOW i am using in5819 anyways thanks for your help
and keen interest I think my pcb design is not good maybe thats reason for
amp blowing up so many times sometimes we have to learn the hard way but i am learning something and that counts for me ill keep trying
warm regards
andrew lebon
Hi Norazmi
greetings thanks for your helpful replies d class very new to me
1 MOSFETS irf250n with gate resistors 27 ohms just finished testing egtagles
orignal pcb with 55 volts dc rails working good i think 60 volts dc is max limit
for IRFP250N using mje13007 instead of TIP 41 resistor 6.8k 1 watt getting about 11.8 volts dc on emitter of mje now on new PCB on supply rails i only added 470 uf 100 volts and .1 cap in addition to the 2 1uf 100volt caps on each rail components DAMAGED
12 IR2110 gone GATE DIODES BLOW i am using in5819 anyways thanks for your help
and keen interest I think my pcb design is not good maybe thats reason for
amp blowing up so many times sometimes we have to learn the hard way but i am learning something and that counts for me ill keep trying
warm regards
andrew lebon
thank you sir
Hi CPX
greetings also thanks to you i will do THD and IMD measurements just
busy its exam time here the new pcb was designed for my student sameerx1
i know dclass pcb has to be designed with care and many considerations next time i will be more careful good to know many helpful people in this d class thread
warm regards
andrew lebon
Hi CPX
greetings also thanks to you i will do THD and IMD measurements just
busy its exam time here the new pcb was designed for my student sameerx1
i know dclass pcb has to be designed with care and many considerations next time i will be more careful good to know many helpful people in this d class thread
warm regards
andrew lebon
Coffe time all
p/s - watch my fully discrete class D amp here : Fully Discrete Class D UCD Amplifier +/- 50vdc - YouTube
p/s - watch my fully discrete class D amp here : Fully Discrete Class D UCD Amplifier +/- 50vdc - YouTube