Tailoring inductor and capacitor circuit models to frequency-domain measurements

The effect of capacitor equivalent series inductance on DC-DC converter performance and stability

“…This paper has included the Filter Capacitor ESL in the modeling of a DC-DC converter. The impedance frequency response of a typical power stage capacitor has been shown by [5] to exhibit the characteristics of an inductor at high frequencies. This effect has been extended into the examination of the effect of the ESL on converter performance and stability.…”

“…Comparing (4) to the transfer function without ESL (5), some significant differences can be clearly seen. (5) The system has increased by one order from two to three with the inclusion of the ESL into the model. Naturally, the transfer function has also increased in like manner.…”

“…(It can be in the hundred's of nano-henries, if the wire lead length is taken into account.) However, the results shown in reference [5] indicate that a practical capacitor does exhibit inductive characteristics in certain frequency ranges. The fixed-topology capacitor model shown in figure 2 was shown to exhibit close agreement between measured and predicted impedances The difference between figures 1 and 2 can be illustrated by simulating the frequency response.…”