Novel High-Frequency Electrical Characterization Technique for Magnetic Passive Devices

Integrated magnetic components are key elements of the power supply on chip modules. Due to the application requirements, these magnetic devices work at very high frequency and have low inductances. Conventional small-signal tests do not provide all the required information about the magnetic device. Hence, it is important to develop new setups to apply large signals to accurately measure the performance of devices under realistic operating conditions, including nonlinear core effects. The proposed experimental setup is suitable to measure the device impedance under different large-signal test conditions, similar to those in the actual converter, since the excitation current can be configured through every winding: ac current up to 0.5 A at frequencies up to 120 MHz and dc bias current up to 2 A through one or both windings. Voltage and current are measured using commercial instrumentation. Due to the characteristics of the probes and the high frequency of the test, the attenuation and delay due to the probes and the experimental setup have to be taken into account when processing the voltage and current waveforms to calculate the impedances. The compensation test to calculate this attenuation and delay is described. Finally, the proposed setup is validated by measuring a two-phase coupled inductor microfabricated on silicon.