Tekko!
It can work with IRFP460 (somehow), but surely this is not the best choice. IRF540N is much cheaper and better (faster, easier to drive, have higher efficiency) if you have only 50-60V supply.
Thanks! You are right: in this amp I used very fast FETs with Rds=0,036 ohm, Vdsmax=150 V, 2 paralelled, in full bridge. Protection takes account chip temperature, so it allows higher current for short time, this results a ~120 A peak current (I measured it with 2 ms impulses on 0,1 ohm load). In real overload-test I attached 7 pcs of 8 ohm speakers parallel (Eminence Kappa 15 Pro), and overdrived by 2-3 dB with bass signal, and protection tripped 3-4 times in 15 minutes. Temperature of heat sink stayed below 50 degrees. The reason why I call it "2kW amp" is at the time of specification I didn't have big enough stabilized power supply, and also I wanted to have significant headroom for music signal.
It can work with IRFP460 (somehow), but surely this is not the best choice. IRF540N is much cheaper and better (faster, easier to drive, have higher efficiency) if you have only 50-60V supply.
Thanks! You are right: in this amp I used very fast FETs with Rds=0,036 ohm, Vdsmax=150 V, 2 paralelled, in full bridge. Protection takes account chip temperature, so it allows higher current for short time, this results a ~120 A peak current (I measured it with 2 ms impulses on 0,1 ohm load). In real overload-test I attached 7 pcs of 8 ohm speakers parallel (Eminence Kappa 15 Pro), and overdrived by 2-3 dB with bass signal, and protection tripped 3-4 times in 15 minutes. Temperature of heat sink stayed below 50 degrees. The reason why I call it "2kW amp" is at the time of specification I didn't have big enough stabilized power supply, and also I wanted to have significant headroom for music signal.
fokker!
Yes, you are right, it can't be loaded with lower impedance. But then You have to tell what is this impedance exactly!
tekko!
Fokker is only making a bad joke in connection with an earlyer debate.
You don't have to pay, but if you want, you can pay with your IRFP460s! 1*IRFP460=3*IRF540N. OK?
Yes, you are right, it can't be loaded with lower impedance. But then You have to tell what is this impedance exactly!
tekko!
Fokker is only making a bad joke in connection with an earlyer debate.
You don't have to pay, but if you want, you can pay with your IRFP460s! 1*IRFP460=3*IRF540N. OK?
Pafi said:Yes, you are right, it can't be loaded with lower impedance. But then You have to tell what is this impedance exactly!
I will let you the expert answer that tricky question.
Pafi said:
I was just telling the truth, as told by Pafi: this amp cannot be loaded with lower impedance. Pafi said it himself, many times over.
My amp need to be 2ohm stable @ full power (atleast 100-200W) and still have plenty of marginal for dropping speaker impedance before blowing up, or it shouldent even blow up if its taken to maximum power (atleast 100-200W) into a dead short, it should only hum from the PT off the shorted output and then fuse should break.
Is this even remotely possible ?
Is this even remotely possible ?
fokker!
No, if you want to swap the roles, then be consistent, and answer! I've already answered it earlyer, why should I repeat it?
Actually this is not true, because I talked about a different amp, and in a context wich is not existing now! Also you forgot about one half of my statement, wich was the most important part.
So please don't pretend that you really want to discuss about something!
Tekko!
With 4*1 IRF540N it can be 2 ohm stable, not with plenty of headroom, but with some. With 4*2 IRF540N it can have much headroom, but proper layout is significantly harder to achieve. If you had any choice, then I would suggest to use IRF540Z, or FDP3652, or...
This is practically impossible to achieve without an additional protection circuit, no matter what FET do you use.
Sorry, I don't understand these sentences.
No, if you want to swap the roles, then be consistent, and answer! I've already answered it earlyer, why should I repeat it?
Actually this is not true, because I talked about a different amp, and in a context wich is not existing now! Also you forgot about one half of my statement, wich was the most important part.
So please don't pretend that you really want to discuss about something!
Tekko!
With 4*1 IRF540N it can be 2 ohm stable, not with plenty of headroom, but with some. With 4*2 IRF540N it can have much headroom, but proper layout is significantly harder to achieve. If you had any choice, then I would suggest to use IRF540Z, or FDP3652, or...
This is practically impossible to achieve without an additional protection circuit, no matter what FET do you use.
Sorry, I don't understand these sentences.
not to mention that Pafi's amp has a low efficiency of 18.4%.
and it cannot be loaded with a lower impedance!
guys, watch out.
"because I talked about a different amp, and in a context wich is not existing now! "
are you saying that I cannot find a low enough load that once loaded to your amp, it wouldn't blow? Are you telling us that your amp couldn't suffer from mosfet overheat at low enough of a load? are you telling us that physics doesn't apply to your amp?
and it cannot be loaded with a lower impedance!
guys, watch out.
"because I talked about a different amp, and in a context wich is not existing now! "
are you saying that I cannot find a low enough load that once loaded to your amp, it wouldn't blow? Are you telling us that your amp couldn't suffer from mosfet overheat at low enough of a load? are you telling us that physics doesn't apply to your amp?
Pafi said:
Sounding like you use the IRFBB52N15D, or similar.
Yupp, I also think that these devices are capable for a 1 Ohm load in full bridge if you parallel two.
I am planning a full bridge for 2 Ohms without paralleling them and rails of +/- 55V.
These devices are rated for 60A continously at 25C and still 43A continously at 100C and pulsed currents up to 240A. Not so bad, I think.
... Pafi, how does your output filter look?
Mine is getting slightly large, because I am going to use up some existing ferrite cores from my assortment.
But in any case chokes with low distorsion 45 uH, saturation level around 60Ap, and 10-15Arms current capability have some size.
And you would need double current capability...
Mine is getting slightly large, because I am going to use up some existing ferrite cores from my assortment.
But in any case chokes with low distorsion 45 uH, saturation level around 60Ap, and 10-15Arms current capability have some size.
And you would need double current capability...
ChocoHolic
If you use full bridge, you can use output coil in common mode with reverse phase direction...That reduce the size by 4 of the core if you can wind the right wire size for RMS current handling!
I'm sorry, but someone could explain me why fokker always came back with is stupid question of low impedance? I think that is no relation with any topic in this forum...Or I miss something?
Fredos
If you use full bridge, you can use output coil in common mode with reverse phase direction...That reduce the size by 4 of the core if you can wind the right wire size for RMS current handling!
I'm sorry, but someone could explain me why fokker always came back with is stupid question of low impedance? I think that is no relation with any topic in this forum...Or I miss something?
Fredos
...uhps... I thought I would know about chokes, coupled chokes & magnetics in general.. But I do not get the meaning of your explanation.
I would agree that a coupled inductor can be smaller because using a larger core (instead of two) can provide the same Ae while the copper length per turn is just factor 1.41 longer vs. each single choke..., and no of turns needed... resulting factor 1.41 less copper resistance... (ignoring all HF losses for first).
But let's move this dicsussion to an other thread.
I don't want to spoil Tekko's thread with off topics.
May be this thread could need some new ideas:
http://www.diyaudio.com/forums/showthread.php?s=&threadid=87789&perpage=10&pagenumber=1
BTW:
Forget the emotional attacks from fokker. There was a fruitless struggle thread..., but I cannot understand his massive emotional involvement.
I would agree that a coupled inductor can be smaller because using a larger core (instead of two) can provide the same Ae while the copper length per turn is just factor 1.41 longer vs. each single choke..., and no of turns needed... resulting factor 1.41 less copper resistance... (ignoring all HF losses for first).
But let's move this dicsussion to an other thread.
I don't want to spoil Tekko's thread with off topics.
May be this thread could need some new ideas:
http://www.diyaudio.com/forums/showthread.php?s=&threadid=87789&perpage=10&pagenumber=1
BTW:
Forget the emotional attacks from fokker. There was a fruitless struggle thread..., but I cannot understand his massive emotional involvement.
Im gonna use two stacked T106-2 cores with half the space filled with each winding or something.
Still i need to come up with some 2ohm stable fets so i dont need a second gate driver ic for a second set of fets.
Any sponsors ? As im not allowed to buy any components or related stuff for the next 2 years...
Still i need to come up with some 2ohm stable fets so i dont need a second gate driver ic for a second set of fets.
Any sponsors ? As im not allowed to buy any components or related stuff for the next 2 years...
- Status
- This old topic is closed. If you want to reopen this topic, contact a moderator using the "Report Post" button.