High efficiency DC-DC converter with auto-mode transition for mobile SOC applications

Abstract

This paper describes an integrated dual-mode DC-DC converter and its seamless auto-mode transition between the pulse frequency modulation (PFM) and the pulse width modulation (PWM), resulting in reduced inductor current peak and output voltage overshoot. The key idea of auto-mode transition is to keep a control voltage level as a constant by forming a negative feedback loop with a compensator in the PFM operation. The DC-DC converter was implemented in the L6LP (65 nm) process and achieved maximum 91% of measured efficiency for the load current ranging from 5 mA to 200 mA.