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Closed-Loop Buck Converter

Power electronics

A synchronous step-down converter with a continuous-time $L$ – $C$ state solver and switching-ripple reconstruction. Sweep duty cycle, source voltage, load, inductance, capacitance, and carrier frequency; the laboratory identifies conduction mode, efficiency, ripple, and transient settling in real time.

12 components · 15 connections · continuous-time averaged state space

recommended lab 6 of 11

Predict averaged buck-converter output and recognize conduction-mode boundaries.

Builds on: Dynamic RC Low-Pass Filter

predict · then test

In continuous conduction, increase $D$ while $V_{in}$ stays fixed. What should $v_o$ do?

Commit before the explanation appears. This is a prediction, not a quiz score.

governing model

\dot i_L = \dfrac{D V_{in}-v_o}{L},\quad \dot v_o = \dfrac{i_L-v_o/R}{C}

structural inventory

PWM feedback controller
PMOS high-side switch
Schottky freewheel diode
$L$ – $C$ output network

boundaries

$V_{in}: 5$ – $36\ \mathrm V$
$f_{sw}: 20$ – $500\ \mathrm{kHz}$
CCM / BCM / DCM classification

diagnosis challenge Fault identity withheld: infer it from the changed outputs first.

causal signal trace paused

Sample demand The controller compares feedback against the regulation target.

t_{\mathrm{stage}}=\htmlData{math-slot=value}{\mathtt{0.00}}\,\mathrm{s}

step 1 / 5 Sample demand

control console

operating-point presets

V_{\mathrm{in}}=\htmlData{math-slot=value}{\mathtt{00.0}}\,\mathrm V

D=\htmlData{math-slot=value}{\mathtt{00.0}}\%

R_{\mathrm{load}}=\htmlData{math-slot=value}{\mathtt{00.0}}\,\Omega

L=\htmlData{math-slot=value}{\mathtt{000}}\,\mathrm{\mu H}

C=\htmlData{math-slot=value}{\mathtt{000}}\,\mathrm{\mu F}

f_{\mathrm{sw}}=\htmlData{math-slot=value}{\mathtt{000}}\,\mathrm{kHz}

switchboard · fault injection

inject hidden fault

test bed · mode=full

Closed-Loop Buck Converter

instrumentation rack

conduction regime CCM inductor current stays above zero

V_{\mathrm{out}}=\htmlData{math-slot=output}{\mathtt{00.000}}\,\mathrm V\quad V_{\mathrm{ideal}}=\htmlData{math-slot=ideal}{\mathtt{00.00}}\,\mathrm V

I_{\mathrm{load}}=\htmlData{math-slot=load}{\mathtt{0.000}}\,\mathrm A\quad i_L=\htmlData{math-slot=inductor}{\mathtt{0.000}}\,\mathrm A

\Delta i_L=\htmlData{math-slot=value}{\mathtt{0.000}}\,\mathrm{A_{pp}}

\Delta v_o=\htmlData{math-slot=value}{\mathtt{00.0}}\,\mathrm{mV_{pp}}

\eta_{\mathrm{est}}=\htmlData{math-slot=value}{\mathtt{00.0}}\%

SW
$i_L$
$v_o$

switching reconstruction

diagnostic probe