A Quasi-V2 Hysteretic Buck Converter With Adaptive COT Control for Fast DVS and Load-Transient Response in RF Applications

Abstract

This brief proposes a buck converter with adaptive constant on time (ACOT) control, including transient-enhanced technique for fast dynamic voltage scaling (DVS) and load-transient response in RF applications. The proposed ACOT control achieves high performance in DVS tracking response to shorten up-tracking time and down-tracking time. Moreover, the high bandwidth transient-enhanced technique in ACOT control improves load-transient response suffering from low bandwidth compensation loop. In addition, the proposed buck converter operates at 2.5 MHz for high power density and 90.1% peak efficiency. This brief is implemented by TSMC 0.18 $\mu \text{m}$ 1P6M CMOS technology with a chip area 1.81 mm2. Measurement results achieve that the output voltage have both 0.6 $\mu \text{s}$ and 0.6 $\mu \text{s}$ recovery time in 600 mA step-up load and 600 mA step-down load, respectively. For 0.6 V step, the output voltage have both 2 $\mu \text{s}$ in up-tracking time and down-tracking time.