A Spur-Reduction DC–DC Converter With Active Ripple Cancelation Technique

This paper presents an active ripple cancelation (ARC) technique for reducing the switching harmonics of the output voltage of a dc-dc converter. An ARC module injects an ac current to accurately cancel the inductor current ripple while the switching converter provides the dc output current. As a result, the output spur of the switching converter can be reduced effectively. However, due to the ARC module, the proposed power converter includes two complex poles. To ensure the system stability and achieve accurate ripple cancelation, a proposed control method and an adaptive phase-lock circuit are utilized. Furthermore, the ripple cancelation capability is independent of duty cycle, load current, and other converter parameters. The measurement results demonstrate that the switching spur reduction with ARC technique can achieve 28 dB while the noise floor is kept the same.