Week 08
Feedback Stability
I study differential stages, feedback, filters, and output stages as one connected signal path.
What I connect in this unit
Phase margin at the zero-dB loop-gain crossing and gain margin at the −180-degree phase crossing measure distance from oscillation. Dominant-pole compensation moves the first pole lower so later pole delays do not accumulate before unity gain.
Concept map
- Phase margin
- Gain margin
- Dominant pole
- Compensation
Technical anchor
If loop phase is −135 degrees at the unity-gain frequency, phase margin is 45 degrees; increasing compensation capacitance usually lowers crossover and increases margin.
How I review it
Read zero-dB and −180-degree crossings from the loop-gain Bode plot, compute both margins, and relate compensation changes to expected step-response ringing.
Connection to the full course
Unit 8 of 12. Unit numbers follow concept dependencies rather than the historical lecture calendar.