If you build this with the inductor spec in the project you can use this data to validate. The core is a Magnetics MPP #C055050A2, 125u permeability. Do not use any tape between windings: there is no creepage / clearance requirement since this is a non-isolated design and doing so will increase the leakage inductance.

• V1 L=66uH
  • Tested @ 20V, 9uS pulse, V2 open
• V1 leakage L=795nH
  • Tested @ 5V, 1uS pulse, V2 shorted
• V2 L=458uH
  
  • Tested @ 20V, 25uS pulse, V1 open
• V2 leakage L=5.3uH
  • Tested @ 5V, 1uS pulse, V1 shorted

The test jig is a MOSFET driven by a function generator with a large bulk capacitor across the D-S connected to a bench supply. The current ramp is measured with a scope current probe (I use Tek's TCP202). The scope's cursors are used to measure the start/end of the current ramp and the actual rise time (will be longer than the function generator's pulse).

From this the inductance is calculated: L=(V*dt)/di where:

• V=supply voltage
• dt=cursor measured rise time
• di=cursor measured peak current

Parasitic capacitance:

• V1 Fr=1.8MHz, Cp=118pF
• V2Fr=1.56MHz, CP=22pF

This measurements were obtained using a function generator, two passive 1X scope probes, and a 4.7K resistor. One lead of the resistor is connected to a lead of the winding to be measured. The other resistor lead is connected to the function generator's positive lead. The generator's negative lead, along with the scope probe ground leads, are connected to the other lead of the winding. Connect one of the scope probes (say, CH1) to the resistor lead connected to the generator; connect the other probe to the resistors opposite lead (CH2). The other winding should be left open.

Set the scope to trigger on CH1. Program the function generator for a 100kHz, 4V P-P sine wave (no DC offset) and increase in 100kHz increments until the CH2 signal reaches peak amplitude and is in phase with CH1. This is the self resonant frequency (Fr) of the winding. Calculate the parasitic capacitance:

    Cp=1/((2*pi*Fr)^2*L)

Where L is the measured inductance of the winding.