Large-signal power circuit characterization of on-silicon coupled inductors for high frequency integrated voltage regulation

This work describes in detail the design, fabrication and characterization of on-silicon coupled inductors. The coupled inductors are fabricated using a double metal layer process for improved performance. Further, the fabricated devices are characterized for small signal, dc bias and large signal testing at high frequencies (up to 15 MHz). The small signal testing includes both impedance analyzer and network analyzer results for inductance, saturation and coupling data on the device. The paper further describes the design and set-up for a large signal testing system allowing for accurate measurement of inductor performance. The parameters are extracted from the ratio between the voltage complex amplitude and the current complex amplitude for sinusoidal excitation. The proposed system is suitable to perform the measurements under different large-signal conditions given by the ac current amplitudes ranging from 0 A to 0.5 A, at frequencies up to 15 MHz. From the impedance analyzer tests, a self-inductance of 50 nH and a dc bias current of 600 mA was measured. From the large signal test, an ac resistance of 1.4 Ω was measured at 15 MHz and ac current amplitude of 0.5 A. The measured data were in line with design parameters.