Use this electronics calculation for a first-pass component, converter, signal, motor, or sensor estimate when the stated operating conditions and units match the device data.

Input voltage (V)

Required number input.

Output voltage (V)

Required number input.

Primary-to-secondary turns ratio

Required number input.

Compute the flyback converter duty cycle percent as (Vout x Np/Ns) / (Vout x Np/Ns + Vin) x 100. The tool evaluates the supplied inputs together and returns the named outputs below; it does not infer omitted operating conditions or change the units shown.^[1]

Duty cycle (%)

The resulting duty cycle returned as a number.

• Ideal duty-cycle equations omit switch and diode drops, dead time, ripple, discontinuous conduction, magnetic loss, control-loop limits, minimum on-time, startup, and load transients. Use the converter topology and controller datasheet for a realizable design.
• Use finite inputs in the displayed units and preserve more precision than the final presentation requires. Independently verify safety-critical, financial, compliance, or production decisions.

Check the result against the current datasheet and worst-case operating corners, then verify the circuit or measurement with simulation and bench testing where failure matters.

• Forward Duty Cycle

  Compute the ideal forward-converter duty cycle as Vout / (Vin x Ns/Np) x 100 and reject unattainable ratios above 100 percent; the design's transformer-reset limit must be checked separately.

• Boost Duty Cycle

  Compute the ideal boost converter duty cycle percent as (1 - Vin/Vout) x 100.

• Buck-Boost Duty

  Compute the inverting buck-boost duty cycle percent as |Vout| / (Vin + |Vout|) x 100.