Switching regulator with integrated resonant circuit for ripple filtering

摘要

A switching regulator IC contains both switching regulator circuitry and an inductor and a capacitor connected in parallel to form a resonant circuit having an associated notch filter frequency response arranged such that, when connected to receive the regulated output voltage, the resonant circuit attenuates the ripple component. This is accomplished by matching the resonant notch to the ripple's fundamental frequency, either manually or automatically. In addition, the resonant circuit's inductor and capacitor can act in concert with decoupling capacitors coupled to the load to form a low pass filter which attenuates harmonics of the ripple's fundamental frequency.