Switching Regulator (Buck) Component Calculator mechanism

Model scope

NEEDS_REVIEW because the exact capacitor formula and the definitions of current and voltage ripple are missing. The four capacitor outputs are conditional results using the ideal CCM triangular-ripple formula Cout=ΔIL/(8·f·ΔVout); they must not be presented as unqualified design values. The existing honest-label warning is appropriate but should explicitly mention the capacitor ripple model, CCM validity, ESR, ripple-current rating, and input constraints.

• D=Vout/Vin is the ideal continuous-conduction, lossless buck duty-cycle formula; it requires Vin>0 and normally 0<Vout<Vin. It omits switch, diode, inductor, and conduction losses.
• L=(Vin−Vout)·D/(f·ΔIL) is correct for ideal CCM operation when f is switching frequency in hertz and ΔIL is the peak-to-peak inductor-ripple current in amperes.
• The capacitance formula is not specified. “Cout from ΔVout ripple spec” is ambiguous: an ideal-capacitor triangular-ripple estimate is Cout=ΔIL/(8·f·ΔVout), but ESR ripple, ripple-current rating, control-loop constraints, and the definition of ΔVout must also be addressed.
• Peak inductor current is listed as an output but no formula is supplied. Under average-current CCM with triangular ripple, Ipk=Iout+ΔIL/2.
• The specification does not define whether ripple percentages are relative to Iout and Vout, nor whether ripple values are peak-to-peak, peak, or RMS.

Units and conventions

• Vin and Vout are in volts, Iout and ΔIL are in amperes, switching frequency f is in hertz, L is returned in henries, and Cout is returned in farads.
• The test vectors interpret current-ripple target as peak-to-peak ΔIL=(ripple_current_percent/100)·Iout.
• The test vectors interpret output-voltage-ripple target as peak-to-peak ΔVout=(ripple_voltage_percent/100)·Vout.
• For conditional Cout values, the assumed formula is Cout=ΔIL/(8·f·ΔVout), representing ideal capacitor-only ripple from triangular inductor current.
• The test vectors assume ideal lossless CCM operation and triangular inductor current ripple.

Inspectable vector

One of 4 source-bound review vectors:

{
  "inputs": {
    "Vin_V": 24,
    "Vout_V": 12,
    "Iout_A": 2,
    "switching_frequency_Hz": 500000,
    "current_ripple_percent_of_Iout": 30,
    "voltage_ripple_percent_of_Vout": 1
  },
  "expected_outputs": {
    "duty_cycle": 0.5,
    "inductor_ripple_A_pp": 0.6,
    "inductor_uH": 20,
    "output_capacitor_uF": 1.25,
    "peak_inductor_current_A": 2.3
  },
  "working": "ΔIL=(30/100)·2=0.6 A. D=12/24=0.5. L=(24−12)·0.5/(500000·0.6)=6/300000=0.000020 H=20 µH. ΔVout=(1/100)·12=0.12 V. Cout=0.6/(8·500000·0.12)=0.6/480000=0.00000125 F=1.25 µF. Ipk=2+0.6/2=2.3 A."
}

Failure boundary

BREAK_CLAIMED · SELF_FLAGGED

The calculator specification exposes invalid or ambiguous behavior at Vin=0, produces a nonphysical zero inductance at Vout=Vin, and can produce a negative inductance when Vout exceeds Vin. Ripple-percentage convention is also unspecified and changes the component values.

Other records

Sources and evidence

These pointers bind the page to evidence. They do not grant authority or collapse verification into deployment.

• VERIFIED_LEDGER.json
• evidence-tranche5/tranche5-results.json
• BOUNDARY_HAZARD_CATALOG.json