Analyzing op-amp circuit - Please Help

Thread Starter

cass1111

Joined Nov 18, 2012
2
Hello, I am new to this forum, this is my first post. I need to analyze this circuit and explain/understand what the function of each component is. Can someone please breakdown this circuit to help me better understand it? Help would be greatly appreciated.

* Please click on the attached thumbnail to see the circuit - sorry, I'm still learning how to attach the files so that they post correctly!! *

This is what I have so far...

C1003 - ESD cap
C1011 - bypass cap
IC1000 - op-amp
R1047 - current limiting resistor
R1047 + C1027 - low pass filter

As you can see, I need a lot of help still! And if you could explain it in layman's terms, that would be a huge help!

Thank you again for your time and help!
 

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Thread Starter

cass1111

Joined Nov 18, 2012
2
Jony130... Thank you so much for taking the time to reply and for the direction you have me! I have stepped away from engineering for a few years, so I am trying to shake some rust off in my circuit analysis!

Looking up he Sallen-key low pass filter topology, I figured out how to calculate the resonant frequency and the Q factor. I was wondering though, if this opamp topology is already serving as a low pass filter, what would be the purpose of having R1047 and C1027 also configured as a low pass filter? ... Or is that not their purpose?

Finally, is R1047 also being used as a current limiter? And if so, how would i calculate what the worst case current would be seen going through R1047?

Thanks again to you and anyone else who takes the time to point me in the right direction!
 

Jony130

Joined Feb 17, 2009
5,488
what would be the purpose of having R1047 and C1027 also configured as a low pass filter? ... Or is that not their purpose?
I don't know why they use this RC passive filter. Maybe they need third order filter instead of second order filter.
Finally, is R1047 also being used as a current limiter? And if so, how would i calculate what the worst case current would be seen going through R1047?
TLC2272 don't have any short circuit protection. And also TLC don't like "heavy" loads.
As for selection such a short circuit protection resistor see data sheet figure 18 and 20 on page 35 and use Ohms law.
 
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