Power-Efficient Pulse Width Modulation DC/DC Converters with Zero Voltage Switching Control

This paper proposes a power-efficient PWM DC/DC converter design with a novel zero voltage switching (ZVS) control technique. The ZVS control is realized by an inner feedback loop which is implemented by simple digital circuitry between the input and output of the power transistors and achieves real-time zero voltage switching (ZVS) for various loading and device parameters with power efficiencies over 90.0%. In addition, an outer feedback loop is used to ensure that the output precisely tracks a reference voltage level. We have also built the relationship between the output voltage ripple and the speed of the voltage comparators which has shown to introduce new low-frequency signals to the loops and cause significant output voltage ripples. Experiment results show that the output ripple could be reduced by 4x by carefully handling the generation and propagation of these low frequency signals.

1. INTRODUCTION

Power consumption has become one of the most important issues in modern electronics due to increased complexity and speed of the system. In order to curb the effect of power on a system as a whole, multiple power domains have been proposed as an architecture scheme for low power design. To support multi-Vdd, an array of supply voltages need to be generated. DC/DC converters can be integrated on chip and convert the input voltage to different voltage levels internally. Recently, a great deal of research [1]–[5] has been devoted to improving the power efficiency and reducing the area cost of on-chip DC/DC converters. However, there are still many unsolved problems. For instance, the basiclinear regulator and the charge-recycling voltage regulator are designs that have been looked at as candidates for on-chip integration because there are no filter elements. However, the relative low power efficiency, typically less than 80% [1], of these designs has limited their application.