A Current-Mode Four-Phase Synchronous Buck Converter With Dynamic Dead-Time Control

Abstract

A current-mode four-phase synchronous buck converter with a dynamic dead-time control (DDTC) method is presented in this work. A brief analysis of the multiphase buck converter power efficiency in both continuous conduction mode (CCM) and discontinuous conduction mode (DCM) is performed to provide design guidelines for minimizing power losses. In synchronous converters, the power efficiency can always be improved by optimizing the dead-time. Therefore, a gate driver with DDTC is designed to optimize the dead-time in every switching cycle, thereby improving power efficiency particularly under heavy load conditions. The proposed buck converter has the ability to deliver a maximum load current of 6.0 A at a typical output voltage of 1.2 V from a power supply of 3.0 V. A power efficiency improvement of over 1.0% is achieved when the load current is over 2.0 A, and an improvement of about 2.4% is obtained at a load current of 4.0 A. A peak power efficiency of 92.8% is measured at an output voltage of 1.8 V.

Keywords

• Dynamic dead-time control
• high efficiency
• multiphase
• synchronous buck converter