Stability analysis for a voltage regulator?

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vt600

Joined Jul 30, 2018
15
Following is the circuit I have been analyzing:


This is a buck regulator. Circuit description:
Input voltage : 12 V
Output voltage : 3.3 V
Feedback-path -> Combination of R1 and R2
Additional path -> Differential amplifier path that will be triggered once voltage across the sense resistor voltage is enough to turn-on the diode
Feedback voltage = 1 V


I am interested to calculate phase-margin and gain-margin. If any of you have much idea about transfer-function and feedback stability analysis, kindly advice.Please let me know if their is any further information required.
 

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crutschow

Joined Mar 14, 2008
25,384
The attached paper is a good discussion about stabilizing switching supplies.
It's not a simple subject.
The analysis is done by linearizing the switching supply pulse-width-modulator as a linear amp with gain, with the feedback loop having compensation for the output inductor/capacitor, which forms a resonant circuit.
 

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