Winding techniques to raise SRF

With the advent of higher and higher operating frequencies required of modern magnetic devices it is generally important to have as high a self resonant frequency (SRF) as possible. In the case of the more complex winding techniques required to raise SRF the penalties are increased labor costs, and for the customer, increased system part count. The bifilar winding of center tapped windings greatly lowers the SRF because the entire surface area of the winding (a large capacitor) must be driven by the full output voltage swing. By splitting center tapped windings into separate layers, the SRF will be maximized, however, the leakage inductance between windings will increase. This could result in poorer regulation of the power supply the devices drive. The measurement of SRF is discussed.