Ok i take that back. From output of LM311 to output from fets before output filter i get a total of 251nS on turn on, and 218.7nS when turning off.
A shame i don't have a model for IR2010 to use.
Btw with the same component values as in my prototype, the simulation runs in 660kHz, and as the prototype runs at 460kHz, the propagation delay there is probably even bigger.
150 and 177nS with IRF640, the previous was with IRFB4227.
A shame i don't have a model for IR2010 to use.
Btw with the same component values as in my prototype, the simulation runs in 660kHz, and as the prototype runs at 460kHz, the propagation delay there is probably even bigger.
150 and 177nS with IRF640, the previous was with IRFB4227.
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Hi all,
I hear interesting speeches from Savu or Baldin and job of Tekko But I do not understand the insistence to use a comparator lm311 on audio? is a poor comparator for audio. then it is normal that there is no difference of THD with 250kHz (at 1KHz) you try 2 or 3 high frequency signals and measure intermodulation if you want to see the difference, eg. at 400KHz.
Savu: for my experience (I can demostrate with Measure) TC44xx is not good for driving on 2-3Kpf on gate MOSFET ( Because internal use mosfet complementary and Have rds-on) not good for fast. A very good amplifier requires a chain of solutions, for this reason the concept is simple but very difficult to obtain.
Regards
I hear interesting speeches from Savu or Baldin and job of Tekko But I do not understand the insistence to use a comparator lm311 on audio? is a poor comparator for audio. then it is normal that there is no difference of THD with 250kHz (at 1KHz) you try 2 or 3 high frequency signals and measure intermodulation if you want to see the difference, eg. at 400KHz.
Savu: for my experience (I can demostrate with Measure) TC44xx is not good for driving on 2-3Kpf on gate MOSFET ( Because internal use mosfet complementary and Have rds-on) not good for fast. A very good amplifier requires a chain of solutions, for this reason the concept is simple but very difficult to obtain.
Regards
I plan on replacing the LM311 if i find something better. I tried to sample an LT1016 but they wont accept free email adresses anymore, and at 16 dollars minimum on ebay, its way outta my budget.
Suggestions ? Pin compatible would be nice, so i could just pop it into the prototype for testing.
Suggestions ? Pin compatible would be nice, so i could just pop it into the prototype for testing.
low price compatible pin not know. for try you can use LM319, it is low price but very good performance, solder external just for listen difference.
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Hi,
in my work is easy to try many components (directly from the manufacturer) but fast on datasheet does not mean that it is good to use for audio. MAX eg., some have many "glish" at output.
LM319 output has a very clean and you can put two in parallel (very good) because have high input impedance (this also help feedback) and very low output impedance (this help rise time).
in my work is easy to try many components (directly from the manufacturer) but fast on datasheet does not mean that it is good to use for audio. MAX eg., some have many "glish" at output.
LM319 output has a very clean and you can put two in parallel (very good) because have high input impedance (this also help feedback) and very low output impedance (this help rise time).
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Elfa Sverige
Elfa (All prices are in SEK exclusive of VAT and freight charges)
https://www.elfa.se/elfa3~se_en/elfa/init.do?shop=ELFA_SE-EN#query=LT1016;in=toc;node=0;id=2;
Elfa (All prices are in SEK exclusive of VAT and freight charges)
https://www.elfa.se/elfa3~se_en/elfa/init.do?shop=ELFA_SE-EN#query=LT1016;in=toc;node=0;id=2;
Hi Savu,
I was referring in general lm311.
yes, fast comparator is important for resolution and clearly helps to reduce the propagation time But more speed equals more "glish" and artefact, RFI etc and requires a very nice development of the PCB. very good Class D is ... "bastard in side".
sooner or later I will a Amp with direct-conversion, eliminated some stages.. ..(comparator and mosfet only)
Regards
I was referring in general lm311.
yes, fast comparator is important for resolution and clearly helps to reduce the propagation time But more speed equals more "glish" and artefact, RFI etc and requires a very nice development of the PCB. very good Class D is ... "bastard in side".
sooner or later I will a Amp with direct-conversion, eliminated some stages..
..(comparator and mosfet only)Regards
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Yes the original version of this amp is crap, i used LM311 because it happened to be what i had available in my parts box.
I currently have 187nS propagation delay from comparator output to after the fets before the output filter in my simulation.
With that much propagation delay, i wonder if a comparator with super low propagation delay is really improving anything, unless it adds to the other propagation delays.
Im pretty sure a MAX913 will be a drastic improvement opver the LM311 atleast. And geting rid of that ltp thing with the 4 transistors is likely a big improvement as well.
I currently have 187nS propagation delay from comparator output to after the fets before the output filter in my simulation.
With that much propagation delay, i wonder if a comparator with super low propagation delay is really improving anything, unless it adds to the other propagation delays.
Im pretty sure a MAX913 will be a drastic improvement opver the LM311 atleast. And geting rid of that ltp thing with the 4 transistors is likely a big improvement as well.
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Hi,
First of all for improve performances you have to redesign Q3-q4 stage because actually is very slow (it is passive jmp with very small current).
PWM does not work well at the limits of range.
Then ,not have sense change only comparator.
Hi Savu,
I was referring in general lm311.
yes, fast comparator is important for resolution and clearly helps to reduce the propagation time But more speed equals more "glish" and artefact, RFI etc and requires a very nice development of the PCB. very good Class D is ... "bastard in side".
sooner or later I will a Amp with direct-conversion, eliminated some stages..
Regards
you are right, but if you use all smd package like sop, or even bga or lga, with board make out of copper coated in silver (for better rfi performance) and use shields like in mobile phones you can get some pretty results.
regards,
savu
Hi,
this yes but...runnig only if low side have low voltage,in this case 18v.
and ..you put a heatsink on this bjt?
also, high thd introduce becouse base current is very high!
A part not really possible 6ns. 15-18 ns is allready good...if solve dissipation first, then add other bjt and
story is infinite.
this yes but...runnig only if low side have low voltage,in this case 18v.
and ..you put a heatsink on this bjt?
also, high thd introduce becouse base current is very high!
A part not really possible 6ns. 15-18 ns is allready good...if solve dissipation first, then add other bjt and
story is infinite.
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