Plug-and-play digital controllers for scalable low-power SMPS

This paper describes a self-configured digital controller suitable for use in both single phase and multiphase converter topologies. In multiphase mode, the system operates in a decentralized fashion, where each phase has its own controller. To synchronize phases and minimize inductor current ripple, the controllers configure themselves during a two-step initialization procedure. First, the number of phases is detected via a simple communication protocol. Then, using a charge-based identification process, the LC products among phases are estimated in order to set the phase switching sequence, such that the current ripple is minimized. The operation of the system is demonstrated with a 5 V/1.5 V, 30 W, 4-phase buck experimental prototype operating at a switching frequency of 800 kHz.