The required test frequency is derived from the converter switching frequency. Sinusoidal voltage with a suitable frequency is required for transformer inductance measurements. The R&S®LCX LCR meter can accurately measure all critical transformer parameters. This ensures sufficient protection for the main switching element but also reduced losses and fewer EMI problems.īesides leakage inductance, other parameters such as magnetizing inductance, winding capacitance and winding resistance are relevant and needed for high-quality designs.Īn accurate simulation model can also be derived from the measured parasitic transformer values to accelerate the design process. During the design process, an accurate measurement of leakage inductance on the primary transformer side is essential for an optimized snubber circuit design. The energy stored in the leakage inductance requires snubber circuits to limit voltage in the switching devices.

If the transformer is designed to operate in a flyback converter, the main converter switch will be sensitive to voltage kickback from leakage inductance when the driving transistor turns off. This leakage inductance may cause power losses and influence EMI emissions especially at higher converter switching frequencies. Designing a transformer to obtain greater magnetizing inductance tends to increase leakage inductance, especially if isolation is required between the primary and secondary winding. The impact of leakage inductance from SMPS transformers depends on several factors.

How to design smps transformer