Forward Converter Output

Vout = Vin × D × N2/N1

Quick answer

This calculator solves V_out = V_in × D × (N₂/N₁) for Output Voltage. With Input Voltage 26.4 V, Duty Cycle 50 %, Secondary Turns 1.1, Primary Turns 2.35, the result is 6.179 V. It solves in 3 directions, so you can enter the values you have and get the one you need.

Calculator

Output Voltage (V)
—

Formula

V_out = V_in × D × (N₂/N₁)

Description

The forward converter is an isolated DC-DC topology that transfers energy directly through the transformer during the switch on-time (unlike the flyback which stores energy). The output voltage depends on the input voltage, duty cycle, and turns ratio. It behaves like an isolated buck converter. Forward converters are widely used in the 50-500 W range for telecom power supplies, server PSUs, and industrial equipment. The maximum duty cycle is typically limited to 50% for single-switch forward converters to allow transformer core reset.

Variables

  • V_out — Output voltage (V)
  • V_in — Input voltage (V)
  • D — Duty cycle (0 to 0.5 for single-switch)
  • N₂ — Secondary winding turns
  • N₁ — Primary winding turns

Practical Notes

Active-clamp or two-switch forward converters can operate at duty cycles above 50%. The output inductor and capacitor form an LC filter that smooths the pulsed transformer output into DC. For multiple outputs, additional secondary windings with their own rectifiers and LC filters are used. Cross-regulation between outputs depends on the coupling between secondary windings.

Symbols and units

Symbol Meaning Default unit Accepted units
Vout Output Voltage V pV, nV, µV, mV, V, kV
Vin Input Voltage V pV, nV, µV, mV, V, kV
D Duty Cycle — —, %
N2 Secondary Turns — —
N1 Primary Turns — —

Step by step

  1. 1. What you know: Input Voltage 26.4 V, Duty Cycle 50 %, Secondary Turns 1.1, Primary Turns 2.35
  2. 2. The relation: V_out = V_in × D × (N₂/N₁)
  3. 3. Substitute: Vin = 26.4 V, D = 50 %, N2 = 1.1, N1 = 2.35
  4. 4. Result: Output Voltage = 6.179 V

Worked examples

Minimum range

Given: Input Voltage 0.726 V, Duty Cycle 2.5 %, Secondary Turns 0.055, Primary Turns 0.118

Result: Output Voltage = 8.46 mV

Low range

Given: Input Voltage 7.26 V, Duty Cycle 25 %, Secondary Turns 0.55, Primary Turns 1.18

Result: Output Voltage = 0.846 V

Typical

Given: Input Voltage 26.4 V, Duty Cycle 50 %, Secondary Turns 1.1, Primary Turns 2.35

Result: Output Voltage = 6.179 V

High range

Given: Input Voltage 0.506 kV, Duty Cycle 0.8, Secondary Turns 1.76, Primary Turns 3.76

Result: Output Voltage = 0.1895 kV

Maximum range

Given: Input Voltage 5.06 kV, Duty Cycle 8, Secondary Turns 17.6, Primary Turns 37.6

Result: Output Voltage = 18.95 kV

Solving for each variable

Solve for Output Voltage

Input Voltage 0.726 V, Duty Cycle 2.5 %, Secondary Turns 0.055, Primary Turns 0.118 → 8.46 mV

Solve for Input Voltage

Output Voltage 0.33 V, Duty Cycle 2.5 %, Secondary Turns 0.055, Primary Turns 0.118 → 28.32 V

Solve for Duty Cycle

Output Voltage 0.33 V, Input Voltage 0.726 V, Secondary Turns 0.055, Primary Turns 0.118 → 0.9752

How Output Voltage changes with Input Voltage

Input Voltage (input) Output Voltage (result)
5.81 V 2.992 V
14.53 V 7.479 V
29.05 V 14.96 V
43.58 V 22.44 V
58.1 V 29.92 V
87.15 V 44.87 V
116.2 V 59.83 V
0.2324 kV 119.7 V
0.4067 kV 0.2094 kV
0.581 kV 0.2992 kV

The same result in other units

Unit Value
µV 6179000
mV 6179
V 6.179
kV 0.006179

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Frequently asked questions

How do you calculate Forward Converter Output?

Use V_out = V_in × D × (N₂/N₁). With Input Voltage 26.4 V, Duty Cycle 50 %, Secondary Turns 1.1, Primary Turns 2.35, Output Voltage works out to 6.179 V.

How do you calculate forward converter vo/vin?

Rearrange for Output Voltage: with Input Voltage 7.26 V, Duty Cycle 25 %, Secondary Turns 0.55, Primary Turns 1.18, Output Voltage is 0.846 V.

What is the formula for Forward Converter Output?

The formula is V_out = V_in × D × (N₂/N₁). The forward converter is an isolated DC-DC topology that transfers energy directly through the transformer during the switch on-time (unlike the flyback which stores energy).

How do you find Input Voltage when you know the other values?

Rearrange for Input Voltage: with Output Voltage 0.33 V, Duty Cycle 2.5 %, Secondary Turns 0.055, Primary Turns 0.118, Input Voltage is 28.32 V.

How do you find Duty Cycle when you know the other values?

Rearrange for Duty Cycle: with Output Voltage 0.33 V, Input Voltage 0.726 V, Secondary Turns 0.055, Primary Turns 0.118, Duty Cycle is 0.9752.

What units does Forward Converter Output use?

Output Voltage is shown in µV, mV, V, kV. Values are held in SI base units internally, so you can mix prefixes without converting by hand.

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