1. What is the Flyback Transformer Equation?

The Flyback Transformer Equation calculates the number of primary turns (N_p) needed in a flyback transformer design based on input voltage, on time, flux density change, and core effective area.

2. How Does the Calculator Work?

The calculator uses the Flyback Transformer equation:

Where:

• \( N_p \) — Primary turns
• \( V_{in} \) — Input voltage (V)
• \( t_{on} \) — On time (s)
• \( \Delta B \) — Flux density change (T)
• \( A_e \) — Effective core area (m²)

Explanation: The equation relates the voltage-time product to the core's flux handling capability to determine the required number of turns.

3. Importance of Primary Turns Calculation

Details: Proper calculation of primary turns is essential for efficient energy transfer, preventing core saturation, and achieving desired output voltage in flyback converters.

4. Using the Calculator

Tips: Enter input voltage in volts, on time in seconds, flux density change in tesla, and effective core area in square meters. All values must be positive.

5. Frequently Asked Questions (FAQ)

Q1: What is a typical ΔB value for ferrite cores?
A: For ferrite cores, ΔB is typically 0.2-0.3 T to avoid saturation and leave margin for temperature variations.

Q2: How do I determine the effective core area (A_e)?
A: A_e is provided in the core datasheet and represents the effective cross-sectional area for magnetic flux.

Q3: What affects the choice of t_on?
A: t_on depends on switching frequency and duty cycle (t_on = D/f_sw where D is duty cycle and f_sw is switching frequency).

Q4: How does this relate to secondary turns?
A: Secondary turns (N_s) are calculated based on N_p and the desired output voltage (N_s = N_p × V_out × (1-D) / (V_in × D)).

Q5: What safety margins should I consider?
A: It's common to use 10-20% fewer turns than calculated to account for input voltage variations and ensure core doesn't saturate.