Generation of common-mode currents on PCB power-bus structures

In this paper, a significant generation process of common-mode currents on PCB power-bus structures is theoretically explained and experimentally investigated. Lumped elements connected asymmetrically to the power-bus are identified as the source of these common-mode currents. An analytical expression for the resulting common-mode current is derived, which agrees well with measurements. Furthermore it is shown, that the induced common-mode current can be reduced effectively by providing a low impedance behavior of the power-bus