[TEST] Power supplies #21

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opened 2022-11-16 14:02:02 +08:00 by topquark12 · 3 comments
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Testing buck regulator control loop stability and response.

Test condition:
Load current: 3A
Vout: 5V

Test results:
Phase margin: 93 deg
Gain margin: n/a
Crossover frequency: 3.6 kHz

Comments:

  • Loop response is excessively stable (93 deg PM), sacrificing transient response speed (3.6 kHz Fx).
  • Transfer function Zero at ~3 kHz should be shifted to a lower frequency to increase crossover frequency.
Testing buck regulator control loop stability and response. Test condition: Load current: 3A Vout: 5V Test results: Phase margin: 93 deg Gain margin: n/a Crossover frequency: 3.6 kHz Comments: - Loop response is excessively stable (93 deg PM), sacrificing transient response speed (3.6 kHz Fx). - Transfer function Zero at ~3 kHz should be shifted to a lower frequency to increase crossover frequency.

Buck regulator load step response

Test condition:
Base load: 1A
Step load: 3A
Slew rate: 2.5A/us
Step duration: 1ms

Test results:
Undershoot: 85mV
Response time: 384us

Comments:

  • No ringing or signs of oscillation, overly damped, matching bode plot results.
  • Response can be faster
Buck regulator load step response Test condition: Base load: 1A Step load: 3A Slew rate: 2.5A/us Step duration: 1ms Test results: Undershoot: 85mV Response time: 384us Comments: - No ringing or signs of oscillation, overly damped, matching bode plot results. - Response can be faster

The following changes are made to the frequency compensation network:
C151: 39pF -> DNP
C150: 22nF -> 22nF
R64 : 4k12 -> 15k

Bode plot results:
Phase margin: 95 deg
Gain margin : 11.77 dB
Crossover frequency: 100kHz (27 times increase)

Load step response:
Undershoot: 33mV (61% reduction)

The following changes are made to the frequency compensation network: C151: 39pF -> DNP C150: 22nF -> 22nF R64 : 4k12 -> 15k Bode plot results: Phase margin: 95 deg Gain margin : 11.77 dB Crossover frequency: 100kHz (27 times increase) Load step response: Undershoot: 33mV (61% reduction)
sb10q closed this issue 2024-01-23 18:00:11 +08:00
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Reference: sinara-hw/kirdy#21
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