Design Philosophy of Hysteretic Controller for DC-DC Switching Converters

This paper presents a design oriented analysis methodology for hysteretic switching converters. Based on the analysis and comparison of the different hysteretic control schemes, a design analysis with a specific design example for the hysteretic controller is described. To achieve the fastest up-tracking speed, an optimized gate driver design method is introduced. The integrated hysteretic controller was fabricated using a 1.5 m CMOS process. With an input voltage of 5V, the output voltage can be regulated between 0.5 and 2.5 V. A line regulation of 25mV/V, a load regulation of 0.5% for a 100mA current step, and an output voltage ripple of below 42mV under nominal conditions were obtained. Improvements and trend of hysteretic controller design are discussed.