last time for Stefanoo : HOW SHUNTY WORKS
I use to think about regs in "class" boundaries ...... series reg is B class and
shunt reg is A class - same as in amp classes ; A class is always willing to release
energy , and that is certainly more naturall , than ....... blah blah ..
Anyway - Shunty ; look at schematic , and just cover lower half with sheet of
paper ; upper an lower halves are symmetric , and you really don't need to look at all
this mess to understand how it works ..........
Depending of Shunty's purpose and use - you'll have either xformer in front of
it , or you'll have ready DC voltage (from main amp PSU perhaps) , but in any case
you can use input Graetz , made of D6,,D7,D6a,D7a ; after Graetz - you see multiple
CRCRC bank..... purpose of that is obvious ;
After that - you see plain vannila series reg , made of Q1 and surrounding parts ; it's
regulating voltage is set with D1-D5 zenner string .......... 5 x 10V - 4V (remember
Ugs ? ) = 46 V .
Then you see CCS part of shunt reg , made with Q2,Q3 and few surrounding
parts ; same as with main CCS in Pumpkin -current is set with Ube voltage of Q3/ R7
, and that's 0V65/4E7 = ~140mA ....... so - that CCS is trying all the time to push
140mA through everything after him ,and that's nothing else than Pumpkin's positive
halve , in paralel with shunt part of shunt reg ;
In all shunt reg- load combos , most natural way of current sharing is when
you have same currents through load and shunt element of reg .... it be that element is
active , or passive , or combination of both .
After Q2 CCS , you can see - going right - one little all bipolar Pumpkin ; so -
that's again LTP, cascoded too , just because benefits of cascoding aren't limited on
jfets/mosfets only , but on other active sorts too.....
CCS for LTP is made of Q8/Q9 ; current through it is set by R17 ; base current for Q8
is delivered via R10/R11 string , and C10 is there just for little filtering .cascode is ,
obviously , biased via R3/R14 string .
Far right (sensing side - base of Q5 ) side of LTP is clamped to +5V via U1 ,
and that's voltage reference for 5V , eeny weeny 3-legged chip, which is like reference
zenner in fact ;
Current through U1 is held constant with "micro" CCS , made with Q10/R19
combo .
LTP is trying to always preserve same conditions on both sides ; so - when base of
Q4 feels ( via voltage divider made of R8/WR1+R9 ) something different than 5V , it
is trying to null that difference yoyo-ing current through halves ....
Yoyo-ing current through Q5 is routed via R12 , and that current is resulting in
adequate amount for gentle opening and closing Q11 ;
That critter (Q11) is nothing else than good old BJT Darlington ; it needs ~1V3 of
Ub1e2 voltage for full throttle opening ; just imagine it as rheostat , and you'll
understand his role and work here .... when LTP feels that voltage is greater than 36V
( set by tweedling with WR1) , it conducts more current through R12, thus more
opening Q11 , which then eats more current .......
Simple - isn't it .
Stefanoo ;
this - last - time I would not tell you anything more ......... regarding your attitude and knowledge .
take it or leave it
but - I can tell you something about my attitude - don't step anymore on my toes .
I use to think about regs in "class" boundaries ...... series reg is B class and
shunt reg is A class - same as in amp classes ; A class is always willing to release
energy , and that is certainly more naturall , than ....... blah blah ..
Anyway - Shunty ; look at schematic , and just cover lower half with sheet of
paper ; upper an lower halves are symmetric , and you really don't need to look at all
this mess to understand how it works ..........
Depending of Shunty's purpose and use - you'll have either xformer in front of
it , or you'll have ready DC voltage (from main amp PSU perhaps) , but in any case
you can use input Graetz , made of D6,,D7,D6a,D7a ; after Graetz - you see multiple
CRCRC bank..... purpose of that is obvious ;
After that - you see plain vannila series reg , made of Q1 and surrounding parts ; it's
regulating voltage is set with D1-D5 zenner string .......... 5 x 10V - 4V (remember
Ugs ? ) = 46 V .
Then you see CCS part of shunt reg , made with Q2,Q3 and few surrounding
parts ; same as with main CCS in Pumpkin -current is set with Ube voltage of Q3/ R7
, and that's 0V65/4E7 = ~140mA ....... so - that CCS is trying all the time to push
140mA through everything after him ,and that's nothing else than Pumpkin's positive
halve , in paralel with shunt part of shunt reg ;
In all shunt reg- load combos , most natural way of current sharing is when
you have same currents through load and shunt element of reg .... it be that element is
active , or passive , or combination of both .
After Q2 CCS , you can see - going right - one little all bipolar Pumpkin ; so -
that's again LTP, cascoded too , just because benefits of cascoding aren't limited on
jfets/mosfets only , but on other active sorts too.....
CCS for LTP is made of Q8/Q9 ; current through it is set by R17 ; base current for Q8
is delivered via R10/R11 string , and C10 is there just for little filtering .cascode is ,
obviously , biased via R3/R14 string .
Far right (sensing side - base of Q5 ) side of LTP is clamped to +5V via U1 ,
and that's voltage reference for 5V , eeny weeny 3-legged chip, which is like reference
zenner in fact ;
Current through U1 is held constant with "micro" CCS , made with Q10/R19
combo .
LTP is trying to always preserve same conditions on both sides ; so - when base of
Q4 feels ( via voltage divider made of R8/WR1+R9 ) something different than 5V , it
is trying to null that difference yoyo-ing current through halves ....
Yoyo-ing current through Q5 is routed via R12 , and that current is resulting in
adequate amount for gentle opening and closing Q11 ;
That critter (Q11) is nothing else than good old BJT Darlington ; it needs ~1V3 of
Ub1e2 voltage for full throttle opening ; just imagine it as rheostat , and you'll
understand his role and work here .... when LTP feels that voltage is greater than 36V
( set by tweedling with WR1) , it conducts more current through R12, thus more
opening Q11 , which then eats more current .......
Simple - isn't it .
Stefanoo ;
this - last - time I would not tell you anything more ......... regarding your attitude and knowledge .
take it or leave it
but - I can tell you something about my attitude - don't step anymore on my toes .
Re: last time for Stefanoo : HOW SHUNTY WORKS
skipping the part above.......
Just want you to know that what you wrote (thank you) is what is written on the cookbook and i did understand that already.
My question is a little bit far ahead and I have posted here hoping that who built this circuit would know why this is happening...
anyways:
I have put a trimmer on the current sink at the tail of the differential stage.
I have set it at 82ohm in order to have the 8mA sunk by the tail.
the circuit is showing the correct 0.650V across the 4.7ohm resistor and 0.668V across the 82ohm resistor, that would show me that the current source and sink are properly working.
I do also have 1.25V across the 390ohm resistor and that's ok.
What's wrong though, is that i don't have the 5V at the voltage divider.....meaning at the input of the differential amp that would suggest that the shunt is not really shunting all the current....but...wow....i have 1.25V at BE junction of the Darlinton and 0.625V at the 4.7ohm resistor of the current source which would suggest that the whole current is sourced...so.....why don't I have the 5V at the diff input?
If i adjust the trimmer at the current tail i can get then 5V....but then if i try to adjust the output voltage through the variable voltage divider....in some circumstances the voltage doesn't stay at 5V.
I understand that it's not very easy to troubleshoot the circuit from far away....but i don't know somebody might have had the same problem.
I don't know if my description was clear enough...if not sorry....and if there is any further question i will try to answer it.
thanks for the attention.
Zen Mod said:
skipping the part above.......
Just want you to know that what you wrote (thank you) is what is written on the cookbook and i did understand that already.
My question is a little bit far ahead and I have posted here hoping that who built this circuit would know why this is happening...
anyways:
I have put a trimmer on the current sink at the tail of the differential stage.
I have set it at 82ohm in order to have the 8mA sunk by the tail.
the circuit is showing the correct 0.650V across the 4.7ohm resistor and 0.668V across the 82ohm resistor, that would show me that the current source and sink are properly working.
I do also have 1.25V across the 390ohm resistor and that's ok.
What's wrong though, is that i don't have the 5V at the voltage divider.....meaning at the input of the differential amp that would suggest that the shunt is not really shunting all the current....but...wow....i have 1.25V at BE junction of the Darlinton and 0.625V at the 4.7ohm resistor of the current source which would suggest that the whole current is sourced...so.....why don't I have the 5V at the diff input?
If i adjust the trimmer at the current tail i can get then 5V....but then if i try to adjust the output voltage through the variable voltage divider....in some circumstances the voltage doesn't stay at 5V.
I understand that it's not very easy to troubleshoot the circuit from far away....but i don't know somebody might have had the same problem.
I don't know if my description was clear enough...if not sorry....and if there is any further question i will try to answer it.
thanks for the attention.
Hehe ...
Thats nothing new but :
Indeed, cooking and audio tronics are, to some extension, matter of numbers /maths if you want.
You can also follow a receip and produce something tasty even if you're not a big chief yourself.
But to be creative in the field is still another matter.
Measurement are possible too.
But measuring acidity of wine won't tell you much about quality/taste ... but it will tell you if you're drinking vineggar or not
(Just to test the metaphor)
manu
Thats nothing new but :
Indeed, cooking and audio tronics are, to some extension, matter of numbers /maths if you want.
You can also follow a receip and produce something tasty even if you're not a big chief yourself.
But to be creative in the field is still another matter.
Measurement are possible too.
But measuring acidity of wine won't tell you much about quality/taste ... but it will tell you if you're drinking vineggar or not
(Just to test the metaphor)
manu
Lost in Common Mode Chokes
Hello,
I've got some choke questions.
On the shunty JP1 and JP1a can be used for inserting a choke.
If I use a common mode choke do I connect the +voltage (JP1) to one coil of the common mode choke and the -voltage (JP1a) to the other coil of the same common mode choke ? So one common mode coil for one shunty.
Or do I need two common mode coils for one shunty:
connect the +voltage (JP1) to one coil of the common mode choke and cut the ground trace and let it pass through to the other coil of the same common mode choke ?
The same for -voltage (JP1a).
Or something else ?
Will this do the job: 16mH, 0.16ohm, 2.6A choke:
http://search.digikey.com/scripts/DkSearch/dksus.dll?Detail?name=237-1237-ND
Regards,
Danny
Hello,
I've got some choke questions.
On the shunty JP1 and JP1a can be used for inserting a choke.
If I use a common mode choke do I connect the +voltage (JP1) to one coil of the common mode choke and the -voltage (JP1a) to the other coil of the same common mode choke ? So one common mode coil for one shunty.
Or do I need two common mode coils for one shunty:
connect the +voltage (JP1) to one coil of the common mode choke and cut the ground trace and let it pass through to the other coil of the same common mode choke ?
The same for -voltage (JP1a).
Or something else ?
Will this do the job: 16mH, 0.16ohm, 2.6A choke:
http://search.digikey.com/scripts/DkSearch/dksus.dll?Detail?name=237-1237-ND
Regards,
Danny
is overkill ..... so - be it ..... 
:
Variac said:
seriously ?
( pretty strange concept for me
)OK - seriously - if Jason think that's doable with some new board software , why not ..... but - on the other hand - one of main virtues of this ( frankly - and few more good forums ) is archive role of accumulated knowledge and info .
I'm scared with possibility that any wit/wise sentence , usually written and sealed as is , can be just ........ lost in the wind of chat board .....
or I'm just not aware of possibility of some sort of "recording" of chats ?
certainly I'm not good informed , because I'm rarely "chatting" even via Skype .....
hehe , when I'm mentioning wit/wise sentences , I'm certainly not thinking on my self .......
have you some recent chats , regarding chats , with other mods ?
I'm all ears ....