janneman said:
Its not a least intelligent solution, in real world phenomena we call it as an INTELLIGENT POWERWARE SOLUTION.
Things aren't redundant in that way only the relativity associates one solution to another which in our opinion is most exceptional in proworld. you simply cannot say about anything without relation to another, so, its always generous to provide something little bit of extra to counteract the feasible situation in an ergonomic way.
Workhorse said:
Sorry Workhorse,
I cannot follow you here at all. If I can pick up some bits and pieces of text (but I may be wrong in doing so):
- "INTELLIGENT POWERWARE SOLUTION" = that marketing manager again!
- "...in our opinion is most exceptional in proworld": there must be a good reason for it. Others surely will have had the same idea. You may wish to think hard why that is so, before throwing money away.
Jan Didden
Dear Jan Didden,
i completely agree with your sense of understanding which is influenced by the european thinking. in europe people want "more from less" and likewise your opinion also supports it well. You people want to squeeze out maximum from less, but my friend the situation is just an opposite in our country. in our country the people want "even more from more". The regular sound contractor guy here wouldl purchase a 500W mono amp for just 120 dollars which has an overkill of 10 pairs of 2N3773 bipolars at output. its out put is rated at 500W@4 ohms but people here usually connect it to 2 ohms without any problem, and thats certainly an overloaded amp in technical terms. Its a trend or call it a fashion or a mindset of people here, who prefer to buy the stuff which has an overkill type of specs. This cannot be changed over night, it will take some finite time to get the mindset of people to be changed.
We provide overkill to satisfy our customers, whereas we provide intelligent protection to satisfy ourselves and to do justice with product which we manufacture.
What i have said in my earlier post is influenced by Indian market.
and what you have said is an european influence, as simple as simplicity.
i hope it helps in a better understanding between us.
cheers,
Kanwar
i completely agree with your sense of understanding which is influenced by the european thinking. in europe people want "more from less" and likewise your opinion also supports it well. You people want to squeeze out maximum from less, but my friend the situation is just an opposite in our country. in our country the people want "even more from more". The regular sound contractor guy here wouldl purchase a 500W mono amp for just 120 dollars which has an overkill of 10 pairs of 2N3773 bipolars at output. its out put is rated at 500W@4 ohms but people here usually connect it to 2 ohms without any problem, and thats certainly an overloaded amp in technical terms. Its a trend or call it a fashion or a mindset of people here, who prefer to buy the stuff which has an overkill type of specs. This cannot be changed over night, it will take some finite time to get the mindset of people to be changed.
We provide overkill to satisfy our customers, whereas we provide intelligent protection to satisfy ourselves and to do justice with product which we manufacture.
What i have said in my earlier post is influenced by Indian market.
and what you have said is an european influence, as simple as simplicity.
i hope it helps in a better understanding between us.
cheers,
Kanwar
OOPS!
That should read....
and
mikeks said:
True!
VI protection limits current as a function of device voltage..(as Jan pointed out somewhere)....
...while crude short circuit protection provides a constant current limit regardless of device voltage......
...in other words, the short-circuit locus is merely a flat horizontal line across the SOA plot (linear-linear scales assumed)....
...this makes for grossly inefficient use of available SOA, as the flat short-circuit locus HAS to reside below the max. voltage, power dissipation parabola (MOSFETs), or the secondary breakdown parabola (BJTs), leaving more than 90% of available SOA unused.....
Therefore, it should be apparent that simple short-circuit protection is exceedingly crude...and inefficient...and reeks of lack of commitment...laziness.....ineptitude.....cluelessness....rank amateurishness.....(have i missed any choice adjectives here....Let me know...
)
That should read....
and
Regarding the load line,
I have just read through the chapter in D. Selfs book.
I don’t know if I’m allowed to quote, but here goes from page 376, third edition:
“Unwelcome complications are presented by reactive loading. Maximum current no longer coincides with the maximum voltage and vice-versa. A typical reactive load turns the XY (Straight loadline - jens) into an ellipse, which gets much nearer the SOA limit. The width of the ellipse is determined by the amount of reactance involved and since this is another independent variable the diagram could soon become over-complex. The solution is to take the worst case of for all possible reactive loads of the form R+jX and instead of trying to draw hundreds of ellipses to simply show the envelope made up of all their closest approaches to the SOA limit. This is another straight line….”
To the point 2 x VCC on the x axis…..
Does anyone know how to calculate this ellipse – I want to try myself?
\Jens
I have just read through the chapter in D. Selfs book.
I don’t know if I’m allowed to quote, but here goes from page 376, third edition:
“Unwelcome complications are presented by reactive loading. Maximum current no longer coincides with the maximum voltage and vice-versa. A typical reactive load turns the XY (Straight loadline - jens) into an ellipse, which gets much nearer the SOA limit. The width of the ellipse is determined by the amount of reactance involved and since this is another independent variable the diagram could soon become over-complex. The solution is to take the worst case of for all possible reactive loads of the form R+jX and instead of trying to draw hundreds of ellipses to simply show the envelope made up of all their closest approaches to the SOA limit. This is another straight line….”
To the point 2 x VCC on the x axis…..
Does anyone know how to calculate this ellipse – I want to try myself?
\Jens
JensRasmussen said:
This, as i have pointed out elsewhere, has no basis in fact.....
http://www.diyaudio.com/forums/showthread.php?postid=633371#post633371
JensRasmussen said:
Good man!
I am correct in assuming, though, that the equation i've given is self-explanatory?
JensRasmussen said:
I think you mean peak power dissipated.......
No....you do not get it to fit your SOA curve....
Rather, you determine whether it lies within the SOA curve for a single device, or how many devices you need in parallel to ensure that the ellipse thus obtained does not infringe the SOA of each one....
I’m going to simplify it a bit.
P = (Vcc-Vout*sin(wt))*((Vout/|Z|)*sin(wt+p))
Now since the sine has a minimum of -1 and a max of 1 (regardless of p) I rewrite the formula to:
Pmax = (Vcc-Vout*(-1))*((Vout/|Z|)*1)
Vout has a maximum of Vcc so:
Pmax = (Vcc+Vcc)*(Vcc/|Z|) = (2*Vcc)*(Vcc/|Z|) = 2*Vcc^2/|Z|
What say you o master?
\Jens
P = (Vcc-Vout*sin(wt))*((Vout/|Z|)*sin(wt+p))
Now since the sine has a minimum of -1 and a max of 1 (regardless of p) I rewrite the formula to:
Pmax = (Vcc-Vout*(-1))*((Vout/|Z|)*1)
Vout has a maximum of Vcc so:
Pmax = (Vcc+Vcc)*(Vcc/|Z|) = (2*Vcc)*(Vcc/|Z|) = 2*Vcc^2/|Z|
What say you o master?
\Jens
JensRasmussen said:
What else ?
Isnt the easiest to write a few program lines, start the dissipation calculation at Vout =0, make 1 volt steps, and plot the values in a graph ?
You can calculate the differential of the P function and use that to set up a differential equation for an approximate function.
But why bother if you have access to a simulation software package ?
For the soa graph calculate Vce and Ic in mathlab/cat/whatever, use 1 volt steps too, and plot them in the soa graph.
Michael can say things in just one line.
Hi,
it would be easier to look at that spreadsheet I referred the Leach Clone group to. Ben Janssen wrote it & he is looking for confirmation that the formulae & method are correct.
http://www.diyaudio.com/forums/showthread.php?s=&threadid=57446
It's all done in excel with a few sines etc thrown in.
If the spreadsheet is correct it provides an easy and intuitive method to check the output stage against the derated SOAR curve.
it would be easier to look at that spreadsheet I referred the Leach Clone group to. Ben Janssen wrote it & he is looking for confirmation that the formulae & method are correct.
http://www.diyaudio.com/forums/showthread.php?s=&threadid=57446
It's all done in excel with a few sines etc thrown in.
If the spreadsheet is correct it provides an easy and intuitive method to check the output stage against the derated SOAR curve.
- Status
- This old topic is closed. If you want to reopen this topic, contact a moderator using the "Report Post" button.