This capacitor usually has two functions:
1. set the closed-loop HF roll-off
2. add some phase advance to aid loop stability
The first one is easy to calculate, as it is a normal CR response (near enough). The second depends on several other things, including stray capacitances so difficult to calculate.
Some people use a third option:
3. adjust to get a 'good' square wave response
1. set the closed-loop HF roll-off
2. add some phase advance to aid loop stability
The first one is easy to calculate, as it is a normal CR response (near enough). The second depends on several other things, including stray capacitances so difficult to calculate.
Some people use a third option:
3. adjust to get a 'good' square wave response
Thanks!
Could you give me the equation of the closed-loop HF roll-off?
Do you mean this?: 1/(C*R*2PI) = )=-3dB rolloff point
Could you give me the equation of the closed-loop HF roll-off?
Do you mean this?: 1/(C*R*2PI) = )=-3dB rolloff point
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figuring out where to put the corner frequency is a little more complex
Nyquist, Bode worked out the theory ~70 years ago
Nyquist, Bode worked out the theory ~70 years ago
Yes, the equation is easy - deciding what to put in it is the hard part! I assume the OP is not familiar with loop stability theory?
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