Patent ID: 7098745

Claim:
A method comprising: generating a control signal to reduce resonance of a circuit at an operation point, a characteristic of the control signal based on a proximity of an existing operation point to the operation point, wherein generating the control signal comprises: sensing a current associated with an input voltage signal; generating a current-based voltage signal, the current-based voltage signal proportional to the sensed current; modulating the input voltage signal by a first oscillator signal to generate a modulated voltage signal; modulating the current-based voltage signal by a second oscillator signal to generate a modulated current-based voltage signal, the second oscillator signal having a frequency and an amplitude substantially equal to a frequency and amplitude of the first oscillator signal; generating a ratio signal based on a ratio of an amplitude of the modulated current-based voltage signal to an amplitude of the modulated voltage signal; and generating the control signal based on the ratio signal, a phase difference being inversely proportional to the ratio; and controlling an output impedance of a source of the input voltage signal based on the control signal.