Design of a Digital Controller for a Dual-Phase Buck Converter: A Hybrid Approach Integrating Synchronous and Asynchronous Circuits

Power management ICs commonly use DC-DC converters because of their higher efficiency than LDO counterparts. DC-DC converters operate in different modes to keep efficiency constant over different loads, reducing quiescent and dynamic power losses. Switching between modes requires a well-behaved, configurable and adaptable digital control circuit to avoid hazardous states. This paper presents a digital control circuit for a dual-phase buck converter divided into synchronous and asynchronous parts to meet power management requirements. The digital control manages transitions between three different converter modes according to load current: low-power-mode (LPM), single-phase mode (SPM), and dual-phase mode (DPM). Asynchronous logic is responsible for switching control and protection mechanisms while synchronous logic implements time-dependant functionalities. The asynchronous part was designed with STG models and synthesized into a map of standard cells and primitive analog-to-asynchronous (A2A) elements with the Petrify and MPSat tools.