Re: Re: Reply
Hi Siva,
This was choosen to eliminate false muting during Low frequency high current peaks.
hi jan,
The resistor was connected to negative rail in series.
from the onset of short circuit to the muting of input signal, this time was measured along.
Hi Mod,
nice to see your comments too.
Reactive loads have been refered to mismatched loading.
We want to implement a circuit to limit gate drive , not with zeners but with something else, do you have any suggestions for us in order to make things even better.
Regards
kanwar
sivan_and said:
Hi Siva,
This was choosen to eliminate false muting during Low frequency high current peaks.
janneman said:
hi jan,
The resistor was connected to negative rail in series.
from the onset of short circuit to the muting of input signal, this time was measured along.
peranders said:
Hi Mod,
nice to see your comments too.
Reactive loads have been refered to mismatched loading.
We want to implement a circuit to limit gate drive , not with zeners but with something else, do you have any suggestions for us in order to make things even better.
Regards
kanwar
Why can't you use conventional current limiting using source resistors and a transistor connected to the driver?
You claimed in earlier posts that your transistors get destroyed in micro seconds, how come you have 85 ms as reaction time?
A loudspeaker is a pretty reactive load so what does it mean loadwise if you have a mismatched load? What is the difference?
You claimed in earlier posts that your transistors get destroyed in micro seconds, how come you have 85 ms as reaction time?
A loudspeaker is a pretty reactive load so what does it mean loadwise if you have a mismatched load? What is the difference?
Reply
Hi mod,
Your suggestion is good, but this type of protection is not viable as we dont use source resistors, but we look there is also another way similar to this that is measuring the gate drive and muting the input accordingly.
What's your suggestion.
Regarding reactive load, i would like to say that when a INFERIOR quality passive Cross-Over which is causising lot of reactive energy fedback, is connected to amp.
regards,
kanwar
Hi mod,
Your suggestion is good, but this type of protection is not viable as we dont use source resistors, but we look there is also another way similar to this that is measuring the gate drive and muting the input accordingly.
What's your suggestion.
Regarding reactive load, i would like to say that when a INFERIOR quality passive Cross-Over which is causising lot of reactive energy fedback, is connected to amp.
regards,
kanwar
Hi amp_man,
You know, you throw around a lot of comments, and sometimes contradictory stuff, or stuff that very likely has never been tested. It sounds more like wild ideas than tried out things.
We never see any of your famous Work Horse amplifiers. You have no website either.
Are we talking about real hardware, or does this exist between your ears only? Just curious.
Jan Didden
You know, you throw around a lot of comments, and sometimes contradictory stuff, or stuff that very likely has never been tested. It sounds more like wild ideas than tried out things.
We never see any of your famous Work Horse amplifiers. You have no website either.
Are we talking about real hardware, or does this exist between your ears only? Just curious.
Jan Didden
Contradictions, yes. I can't put this together. What is the problem really and what is the possible improvement?
http://www.ahujaradios.com/
http://www.strangeraudio.org/
So at least has competition.
I notice also that Mr amp_man is changing his company name once a week! I have seen at least four different names now?
http://www.ahujaradios.com/
http://www.strangeraudio.org/
So at least has competition.
I notice also that Mr amp_man is changing his company name once a week! I have seen at least four different names now?
Probably nothing but it was intersting to see products from India. They look a bit different.
Some inspiration for Mr amp_man:
http://www.allegromicro.com/hall/currentsensor.asp
50-200 A current sensing modules and up to 50 kHz bandwidth, pretty fast and easy to use, low losses due to the Hall effect.
Some inspiration for Mr amp_man:
http://www.allegromicro.com/hall/currentsensor.asp
50-200 A current sensing modules and up to 50 kHz bandwidth, pretty fast and easy to use, low losses due to the Hall effect.
janneman said:
Jan these type of comments were not expected from you.
our website is under construction, to verify it just look for www.workhorsetechnologiesindia.com in WHOIS database registration of our domain name at www.register.com simply check out and truth will be displayed at front of your eyes.
Nevertheless, Mr. Singh if you show the preset state of your design and state the parts which has a not 100% good function and also that you state your wanted features. At this point you haven't got any specifications for the new protection circuit. Cost I'll imagine is also important.
I may come up with something but right now the specifications are pretty vague.
Note also that I don't mind helping you altough you run a company which has a fully commercial production.
I may come up with something but right now the specifications are pretty vague.
Note also that I don't mind helping you altough you run a company which has a fully commercial production.
Reply
Hi Mod,
i understand what you want to illustrate.
Ok, listen if a gate drive sensor is implemented through optocoupler in series with gate drive limit zener and then its other side used to mute the input signal or simply attentuate the input signal accordingly. Whats your suggesstion .
Regards,
kanwar
Hi Mod,
i understand what you want to illustrate.
Ok, listen if a gate drive sensor is implemented through optocoupler in series with gate drive limit zener and then its other side used to mute the input signal or simply attentuate the input signal accordingly. Whats your suggesstion .
Regards,
kanwar
A good reliable short circuit protection must sense the current more directly, not indirect via a gate voltage. How precise can you control the gate voltage if you have 4-10 pairs of mosfets?
If you manufacture amps this way you won't get any precision at all or repeatablity.
If you calulate worst case with zener tolerance, Vgs and gm, how much can the current differ?
If you manufacture amps this way you won't get any precision at all or repeatablity.
If you calulate worst case with zener tolerance, Vgs and gm, how much can the current differ?
Precise current limiting with Vgs sensing would require precise Vgs comparators, precision Vgs references WITH TEMPERATURE COMPENSATION and trimmed in an unit per unit basis, and closely matched output devices of a model with low enough GM such that output current changes produce high enough Vgs changes
It's far more practical to use source resistors or suitable resistors in series with supply rails or in series with the output before feedback point
Also, using a multi-output SMPS with current limiting in a channel per channel basis may be an interesting option [supply rails may be adjusted to keep SOA]
It's far more practical to use source resistors or suitable resistors in series with supply rails or in series with the output before feedback point
Also, using a multi-output SMPS with current limiting in a channel per channel basis may be an interesting option [supply rails may be adjusted to keep SOA]
No, I get quite pi$$ed off when I review hall-effect sensors because they tend to be high priced and I can't afford them, altough they are very useful. Currently I do experimentation with what I have, and I sense currents with resistors, current transformers or by integrating SMPS inductor voltages 
Reply
Hi mod
i think you are quite a bit right about VGS, So we will rely on traditional method of protection using series resistors.
hi Eva,
Your suggesstion is very good, but we dont have smps supplies in our amps.
One more thing , In your opinion what type of scheme is good:
Continous repititive muting so that it continously monitors the short or a latch type muting is better suited so that user can reset it
regards,
kanwar
Hi mod
i think you are quite a bit right about VGS, So we will rely on traditional method of protection using series resistors.
hi Eva,
Your suggesstion is very good, but we dont have smps supplies in our amps.
One more thing , In your opinion what type of scheme is good:
Continous repititive muting so that it continously monitors the short or a latch type muting is better suited so that user can reset it
regards,
kanwar
I must admit that I haven't checked the price for these new cool integrated current sensing parts but I'll guess for hifi it would be perfect and with very little interference. The current shunt has so little resistance. Is it under 1 mohms? One more positve thing is that they are insulated so you can use any control circuit you like and connect this current shunt anywhere.Eva said:No, I get quite pi$$ed off when I review hall-effect sensors because they tend to be high priced and I can't afford them, altough they are very useful. Currently I do experimentation with what I have, and I sense currents with resistors, current transformers or by integrating SMPS inductor voltages
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