0.293-mm² Fast Transient Response Hysteretic Quasi-V2 DC-DC Converter with Area-Efficient Time-Domain-Based Controller in 0.35-μm CMOS

A time-domain-control-based quasi- V2 buck converter with small area, fast transient response, wide load current range, and constant switching frequency is proposed in this paper. The proposed time-domain-based controller achieves compact core area and simplified constant switching frequency control by replacing the conventional voltage-domain comparator with a phase detector having an adaptive detection window. Moreover, a coupling-based inductor current emulator is also proposed to support the discontinuous conduction mode operation in the light load. The proposed buck converter is implemented using 0.35- μm CMOS process. The core area of the proposed buck converter is only 0.293 mm². The measured peak efficiency in the continuous conduction mode is 92% and the end-to-end efficiency in the load current range of 25-700 mA is 73%. The undershoot/overshoot and recovery time with the up/down load current steps of 510 mA are 38/20 mV and 2.5/2.6 μs , respectively.