MOSFET Switching Power Loss Estimator mechanism

Model scope

The loss equations are acceptable as a simplified hard-switching model when their assumptions are explicit. The specification needs an explicit junction-temperature formula, Ta and θJA inputs, explicit total-loss definition, and unambiguous time units. The honest label should also mention omitted output-capacitance, diode/dead-time, leakage, and temperature-dependent RDS(on) effects.

• Pcond=Irms²×RDS(on) is standard when RDS(on) is the effective operating-temperature resistance and Irms is the MOSFET current RMS value.
• Psw≈½×Vin×Iout×(tr+tf)×fsw is a simplified hard-switching linear-overlap estimate, not a universal MOSFET switching-loss formula. It requires the switched voltage, switching current, and valid rise/fall-time definitions; Vin and Iout may not equal those quantities in every converter topology.
• The claimed optional junction-temperature estimate has no formula and lacks ambient temperature and a required thermal-resistance input. It should explicitly define Tj=Ta+Ptotal×θJA, subject to the limitations of θJA.
• The total-loss formula is not explicitly stated; it should be Ptotal=Pcond+Psw before any optional thermal calculation.

Units and conventions

• RDS(on) is in ohms (Ω), Irms and Iout are in amperes (A), Vin is in volts (V), switching times tr and tf are in seconds (s), and fsw is in hertz (Hz).
• The switching-time inputs must be converted from nanoseconds or other units to seconds before evaluation.
• θJA, if supported, must be in °C/W and ambient temperature Ta must be in °C; the resulting temperature rise is in °C.
• RDS(on) is assumed constant over temperature, gate voltage, current, and switching conditions unless a temperature-corrected value is supplied.

Inspectable vector

One of 4 source-bound review vectors:

{
  "inputs": {
    "RDS_on_ohm": 0.012,
    "Irms_A": 8,
    "Vin_V": 48,
    "Iout_A": 8,
    "tr_s": 3e-8,
    "tf_s": 4e-8,
    "fsw_Hz": 200000
  },
  "expected_outputs": {
    "conduction_loss_W": 0.0768,
    "switching_loss_W": 2.688,
    "total_loss_W": 2.7648
  },
  "working": "Pcond = Irms²×RDS(on) = 8²×0.012 = 64×0.012 = 0.0768 W.\\ntr+tf = 0.00000003+0.00000004 = 0.00000007 s.\\nPsw = 0.5×48×8×0.00000007×200000 = 192×0.014 = 2.688 W.\\nPtotal = 0.0768+2.688 = 2.7648 W."
}

Failure boundary

BREAK_CLAIMED · SELF_FLAGGED

The literal formula accepts negative Iout and produces a negative switching loss instead of rejecting the input or applying a reverse-current model. Extreme magnitudes can also produce Infinity in ordinary JavaScript evaluation, and unlabeled resistance/time units can change the result by orders of magnitude.

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