A method and system for reducing the noise level of a power supply system with the implementation of a voltage controlled decoupling capacitor in an electrical circuit. Voltage variations of the power supply caused by switching currents are detected by a voltage sensor control circuit. The voltage sensor circuit compares a stable reference voltage with the varying voltage level of the power supply in order to generate a sensor control voltage. When applied to the decoupling capacitor, the control voltage adjusts the capacitance of the voltage controlled capacitor. The adjusted capacitance allows the voltage controlled decoupling capacitor to compensate for the effects of the voltage variations by supplying an increased quantity of charge to various circuit components. Thus, the voltage controlled capacitor is able to efficiently reduce noise within the power supply system.