Application example

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Formulas used to calculate electrical characteristics

Connecting windings in series:

• Inductance = Inductance(table) × (number of windings)²
• DCR = DCR(table) × number of windings
• Isat = (Isat(table) × 6) ÷ number of windings connected in series
• Irms = Irms(table)

Connecting windings in parallel:

• Inductance = Inductance(table)
• DCR = 1 ÷ [number of windings × (1 ÷ DCR(table))]
• Isat = (Isat(table) × 6) ÷ number of windings connected in series
• Irms = Irms(table) × number of windings

Create a 13 Watt 2:1:1 flyback transformer with a bias winding

Connecting primary windings in series:
When primary windings (Wpri) are connected in series, inductance increases, energy storage and Irms remain the same, but DCR increases and Isat decreases.

Example: For HPH3-0138L, connect two primary windings in series:

• Inductance = Inductance(table) × Wpri² = 23.6 × 2² = 94.4 μH
• DCR = DCR(table) × Wpri = 0.125 × 2 = 0.25 Ohms
• Isat = (Isat(table) × 6) ÷ Wpri = (0.42 × 6) ÷ 2 = 1.26 A
• Irms = Irms(table) = 1.13

• DCR = 1 ÷ [Wsec × (1 ÷ DCR(table))] = 1 ÷ [(2 × (1 ÷ 0.125)] = 0.0625 Ohms
• Irms = Irms(table) × Wsec = 1.13 × 2 = 2.26 A