The Design of a Fast Transient Response V2 COT Buck DC-DC Converter

This paper presents an adaptive constant on-time control scheme based on V2 constant on-time (V2 COT) architecture with current feedback. Due to the very small equivalent series resistance (ESR) of the output capacitor, stability issues may arise. In this paper, the ripple is obtained by applying two-stage filtering to extract the AC component of SW signal. The ripple is summed with the output signal to form the inner loop. Type-II compensated outer loop is incorporated to enhance output voltage accuracy while preserving the fast transient response characteristic of the ripple-based COT architecture. The designed converter delivers 3.3 V and 5 V outputs from an input range of 8–36 V, with a maximum output current of 35 A and a switching frequency of 510 kHz.