- #1
Dextrine
- 102
- 7
〖 mod note: moved from technical forum, so template is missing 〗
〖 mod note: click on thumbprint image to see legible image 〗
I was wondering if anyone could provide some more insight as to how to find the current through Rc. The first picture TRANSFER1 I can find the current Ic through Rc by the following method:
Ic = (Vin - Vout)/Rc
Vout = -Vin(1/(R*s*C))
Ic = Vin(1+1/(R*s*C))
However, if I add a voltage divider network before the input, the problem becomes much more difficult for me here is my latest attempt:
Ic = (Vin - Vout - I1*R1)/Rc
Vout = (-Vin+I1*R1)/(Ra*s*C)
Ic = Vin + (Vin-I1*R1)/(Ra*s*C) - I1*R1.
Now the problem is that this current will be multiplied by CTR from an optocoupler then multiplied by a pullup resistor to get a voltage Vfb on the other end.
There's no way I can think of to write this equation as Vfb/Vin.
I'm essentially modelling a TL431 and an optocoupler per the following: http://www.onsemi.com/pub_link/Collateral/TND381-D.PDF on page 18I appreciate any help and if this is not the appropriate place to post this, please let me know where I can. I'll keep trying and if I figure it out I'll update this post.
Thanks in advance.
〖 mod note: click on thumbprint image to see legible image 〗
I was wondering if anyone could provide some more insight as to how to find the current through Rc. The first picture TRANSFER1 I can find the current Ic through Rc by the following method:
Ic = (Vin - Vout)/Rc
Vout = -Vin(1/(R*s*C))
Ic = Vin(1+1/(R*s*C))
However, if I add a voltage divider network before the input, the problem becomes much more difficult for me here is my latest attempt:
Ic = (Vin - Vout - I1*R1)/Rc
Vout = (-Vin+I1*R1)/(Ra*s*C)
Ic = Vin + (Vin-I1*R1)/(Ra*s*C) - I1*R1.
Now the problem is that this current will be multiplied by CTR from an optocoupler then multiplied by a pullup resistor to get a voltage Vfb on the other end.
There's no way I can think of to write this equation as Vfb/Vin.
I'm essentially modelling a TL431 and an optocoupler per the following: http://www.onsemi.com/pub_link/Collateral/TND381-D.PDF on page 18I appreciate any help and if this is not the appropriate place to post this, please let me know where I can. I'll keep trying and if I figure it out I'll update this post.
Thanks in advance.
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