Power Electronics
Model class: Exact ideal relationship
Inverting buck-boost designer
Calculate ideal CCM inverting buck-boost duty cycle from input voltage and output magnitude.
Interactive engine
Start with the stated conditions.
Values stay in this browser. Choose a representative scenario, then calculate deliberately.
Example ready
Calculate to inspect the result.
The result will identify the direct answer, assumptions, and any warning that changes the next decision.
Assumptions to check
- The entered inverting-buck-boost values represent the stated operating condition.
- This exact ideal relationship is evaluated in the declared lumped or first-pass model.
- A inverting-buck-boost calculation is not a component qualification or safety approval.
What this inverting-buck-boost calculation establishes
Calculate ideal CCM inverting buck-boost duty cycle from input voltage and output magnitude. The useful result is the stated electrical quantity and the decision it supports, not an unstated claim about a finished product. This engine keeps the governing relationship visible so an input, unit, condition, or model boundary can be reviewed before a value becomes a component or layout choice.
Ideal duty equals output magnitude divided by the sum of input voltage and output magnitude. Treat the number as a first-pass result for the declared operating point. When a source, load, temperature, frequency, waveform, component tolerance, or measurement condition changes, repeat the calculation at the relevant corner rather than assuming the nominal answer persists.
Worked decision context
5 V to -12 V requires ideal duty 12/(5+12), or 0.7059, before losses. That example verifies the equation and illustrates the scale of the result, but it does not select a part by itself. Compare the result with available values, ratings, tolerance bands, and the receiving circuit or physical environment before implementation.
Use the primary output to identify the binding constraint. If it leaves little margin, document which input dominates and use selected-part data, a higher-fidelity model, simulation, or measurement. This is especially important when a small numerical difference changes a thermal, timing, noise, or reliability decision.
Limits and validation handoff
The output ground reference is shifted relative to the input; check downstream circuitry for this reference difference, and add real component losses separately. The calculation does not silently include omitted parasitics, installation conditions, manufacturing variation, or product policy. Those conditions can be decisive even when the arithmetic is exact for the selected model.
Record inputs, units, model assumptions, and the intended decision with the result. Verify the leading risk against the selected component data sheet and a representative measurement when the circuit has consequential energy, high voltage, safety, compliance, or reliability requirements.
Common mistakes
- Treating the inverting-buck-boost result as a guaranteed operating limit rather than a first-pass exact ideal relationship estimate.
- Mixing a data-sheet value measured under one condition with this inverting-buck-boost calculation performed at another.
- Selecting a component before checking the boundary this calculation names: the output ground reference is shifted relative to the input; check downstream circuitry for this reference difference, and add real component losses separately.
Model limit and handoff
Keep the entered inverting-buck-boost conditions with the calculation, then validate the binding limit using the selected component, physical implementation, and representative operating corner.
FAQs
Is this inverting-buck-boost result sufficient to approve a design?
No. It applies exact ideal relationship reasoning to the entered inverting-buck-boost values and names the checks that still need selected-part data, a higher-fidelity model, or measurement. The output ground reference is shifted relative to the input; check downstream circuitry for this reference difference, and add real component losses separately.
What does this inverting-buck-boost calculator assume that could make the result wrong?
Ideal duty equals output magnitude divided by the sum of input voltage and output magnitude. If the entered values do not match the real operating condition, the result no longer describes the actual circuit.
Where should this inverting-buck-boost result go next?
Compare this inverting-buck-boost result with Power converter design workflow, then use the stated next decision below the calculator to move from this first-pass number toward an implementation.