An Efficient Approach to Multiphase Constant On-Time Buck Converter Simulation

The growing demands on microprocessors necessitate advancements in power delivery systems, where multiphase interleaved constant on-time (COT) buck converters stand out for their fast response and high efficiency. While simulations of COT buck circuits are crucial for evaluating circuit performance comprehensively, the inherent complexities in designing these circuits present significant challenges. Particularly, COT buck circuits with an increased number of phases exhibit increased complexity, often leading to simulation issues such as crashes, interruptions, and non-convergence. The absence of a robust and straightforward simulation structure for high-phase-number COT circuits exacerbates these challenges. To mitigate these issues, this paper proposes a novel structure for COT buck circuit modeling that is specifically designed to support phase expansion and facilitate flexible parameter adjustments for generic SPICE level simulator. This structure aims to simplify the simulation process for complex, multiphase COT buck circuits, thereby improving simulation efficiency. Furthermore, to enhance the stability and performance of the multiphase COT buck circuit, we implement a current balancing technique, ensuring uniform current distribution across all phases during transient responses. Simulation results validate the effectiveness of the proposed COT buck circuit model, which demonstrates adaptability to varying circuit parameters and maintains good performance even as the number of phases increases.