An apparatus for canceling an effect of power supply resonance is provided. The effect of power supply resonance is a variation in power supply voltage potential. This variation may substantially affect an output buffer by causing the output buffer's output to sag below desired values. A voltage regulating circuit is coupled to power supply lines local to the output buffer where the voltage regulating circuit is most effective in reducing voltage potential variation. An exemplary voltage regulating circuit is provided that uses charge-pumped capacitors to raise the power supply voltage potential when it falls below a desired value. A second example of a voltage regulating circuit uses charge-pumped capacitors to lower the power supply voltage potential when it rises above a desired value.