Light-Load Efficiency Improvement for Buck Voltage Regulators

Extending battery life is a big challenge for today's laptop, and light-load efficiency is very important for battery life extension. In this paper, adaptive ON-time control is proposed to achieve higher efficiency when the buck converter is running in continuous current mode. A novel nonlinear inductor is then proposed to improve discontinuous-current-mode efficiency. A control method with a thorough analysis is proposed for the nonlinear inductor to achieve high efficiency, the required output voltage ripple, and sufficient transient response. The experimental results demonstrate the benefits of the proposed methods.