A Low Noise High efficiency buck DC-DC converter with sigma-delta modulation
一种基于sigma-delta调制的高效率低噪声降压式直流变换器

Some research efforts on improving efficiency and noise performance of buck DC-DC converter are explored in this paper. A carefully-designed power MOSFET driver, including dead time controller, discontinuous current mode(DCM) controller and gate width controller, is proposed to improve efficiency. Instead of PWM modulation, sigma-delta modulation is introduced into the feedback loop of the converter to move out clock-referred harmonic spike. The proposed converter has been designed and fabricated on a 0.35um CMOS process. Measured results show that the peak efficiency of the converter can reach 93% and sigma-delta modulation suppresses harmonic spike by 30dB over PWM modulation.