A dual-mode digitally controlled converter for synchronous buck converters operating over wide ranges of load currents

A monolithic digitally controlled Pulse Width Modulation/Pulse Skip Modulation (PWM/PSM) dual-mode converter for synchronous buck DC/DC converters is proposed in this paper. The controller operates in PWM during Continuous Conduction Mode(CCM) at 2MHz switching frequency while PSM is adopted to reduce switching loss at Discontinuous Conduction Mode(DCM). Several blocks, including a low power Analog-Digital Converter (ADC), a high resolution and linearity Digital Pulse Width Modulator (DPWM) with a digital DLL and a PSM controller, are described in detail. The converter is simulated in a standard 0.13μm CMOS process, and the simulation results show the high efficiency over a wide of load and fast transient response of digital converter.