US 2009/0153239 A1 · VARIABLE-IMPEDANCE GATED DECOUPLING CELL

Abstract

Embodiments of the present invention provide a system that controls noise in a power system that includes a power rail and a ground rail. The system includes a MOS transistor coupled in series with a decoupling capacitor between the power rail and the ground rail and an inductive packaging connection coupled to the power rail in parallel with the MOS transistor and the decoupling capacitor. The combination of MOS transistor, decoupling capacitor, and inductive packaging connection form a resonant circuit. During operation, the system determines if there is noise in a Vdd signal on the power rail. Based on the noise present in the Vdd signal, the system adjusts the impedance of the MOS transistor to reduce the noise in a frequency range near a frequency of interest (ωinterest) of the resonant circuit without causing an unnecessary increase in switching noise at other frequencies.

Claims30

Dependent claims

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 in series with 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 within an input coupled to the power rail and an output coupled to a gate of the MOS transistor, wherein the control circuit is configured to determine a noise in the Vdd signal;
wherein the control circuit is configured to adjust a voltage applied to the gate of the MOS transistor based on the noise in the Vdd signal, thereby changing an impedance of the MOS transistor to reduce the noise in a frequency range near a frequency of interest (ωinterest) of the resonant circuit without causing an unnecessary increase in switching noise at other frequencies.

3 more elements

A semiconductor chip for controlling noise in a power system that includes a power rail and a ground rail, comprising:

a set of circuitry coupled between the power rail and the ground rail, wherein the power rail and the ground rail provide electrical power for the set of circuitry;
a decoupling capacitor having a first lead which is coupled to the ground rail;
a MOS transistor coupled in series with 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 within an input coupled to the power rail and an output coupled to a gate of the MOS transistor, wherein the control circuit is configured to determine a noise in the Vdd signal;
wherein the control circuit is configured to adjust a voltage applied to the gate of the MOS transistor based on the noise in the Vdd signal, thereby changing an impedance of the MOS transistor to reduce the noise in a frequency range near a frequency of interest (ωinterest) of the resonant circuit without causing an unnecessary increase in switching noise at other frequencies.

4 more elements

A method for controlling noise in a power system that includes a power rail coupled to an inductive packaging connection, a ground rail, a MOS transistor, and a decoupling capacitor, wherein a source of the MOS transistor coupled to the power rail and a drain of the MOS transistor is coupled to the ground rail through the decoupling capacitor, and wherein the MOS transistor and the decoupling capacitor are in parallel with the inductive packaging connection, thereby forming a resonant circuit, the method comprising:

detecting noise in a Vdd signal on the power rail;
based on the detected noise in the Vdd signal, adjusting a voltage applied to the gate of the MOS transistor, thereby changing an impedance of the MOS transistor to reduce the noise in a frequency range near a frequency of interest (ωinterest) of the resonant circuit without causing an unnecessary increase in switching noise at other frequencies.

Dependencies are inferred from the claim text.

Variable-impedance gated decoupling cell

Life of this patent

Variable-impedance gated decoupling cell

Life of this patent

Abstract

Claims30