A Phase Interpolated Dual-Phase Adaptive On-Time Controlled Buck Converter

This paper introduces a dual-phase buck converter that utilizes a phase interpolator for interleaving, based on adaptive on-time control. This method successfully resolves ripple cancellation challenges in multi-phase adaptive on-time controlled buck converters, thereby eliminating the reliance on external ramp signals or complex phase-locked loops. Consequently, the loop bandwidth is expanded, enhancing the converter’s noise immunity and reducing jitter within a compact circuit design. Operating at 3 MHz per phase, the converter demonstrates a maximum jitter of 30.25 ns and a phase error of 7.3 degrees at the ripple cancellation point. Moreover, features like rapid transient on-time extension and a dual-phase full turn-on mechanism significantly improve dynamic performance during load transitions. Experimental results show a voltage drop of 80 mV and a settling time of $2~\mu $ s under a 3 A load step, with input and output voltages of 1.8 V and 0.9 V, respectively. Fabricated using the TSMC $0.18~\mu $ m CMOS process, the prototype boasts a compact total area of 1.41 mm2, including a 0.03 mm2 phase-interpolator section, achieving a peak efficiency of 95.58%.