Mismatch-error noise-shaping based digital multiphase modulator

This paper proposes a multiphase modulator (MPM) for digitally-controlled multiphase buck converters. A recently developed power digital-to-analog converter (DAC) approach allow mismatch-error noise-shaping techniques to be used to build a very simple, hardware-efficient MPM. The proposed modulator is able to generate the control pulses for each phase using a single, low-frequency clock, and to achieve automatic current-sharing among the phases. Furthermore, it enables the designer to achieve the full dynamic capabilities of the multiphase converter. This paper describes the advantages and drawbacks of the proposed modulator and a possible, simple implementation. Simulations and experimental results that demonstrate operation of an 8-phase converter are also shown. The proposed MPM is especially suitable to implement a step-based envelope tracking system for supplying linear radiofrequency power amplifiers.