Patent ID: 7701277
Filing Date: 2010-04-20
Classification: H01L

Abstract:
1. An apparatus for controlling noise in a power system that includes a power rail and a ground rail, comprising: a decoupling capacitor having a first lead which is coupled to the ground rail; a MOS transistor coupled to the decoupling capacitor, wherein a source of the MOS transistor is coupled to the power rail and a drain of the MOS transistor is coupled to a second lead on the decoupling capacitor; an inductive packaging connection coupled to the power rail, wherein the MOS transistor and the decoupling capacitor are configured to be in parallel with the inductive packaging connection, thereby forming a resonant circuit; and a control circuit with an input coupled to the power rail and an output coupled to a gate of the MOS transistor, wherein the control circuit adjusts a voltage applied to the gate of the MOS transistor, thereby changing an impedance of the MOS transistor to reduce a noise in a frequency range near a frequency of interest (ω