A New Improved Ultra-Fast-Response Low-Transient-Voltage Buck Converter With Transient-Acceleration Loops and V-Cubic Techniques

This paper presents a new improved ultra-fast-response low-transient-voltage buck converter with transient-acceleration loops and V-cubic techniques. Firstly, the proposed buck converter is based on optimum-damping control, so it is necessary to add a slope-compensation circuit to accelerate the transient response and decrease the transient voltage. Secondly, the proposed converter utilized the adaptive on-time controlled and V-cubic techniques to stabilize the switching frequency and promote the conversion efficiency. Thirdly, we utilized a rail-to-rail operational transconductance amplifier, which was used as a current-sensing circuit, to reach the feature of wide input range, so that it can directly sense the voltage without voltage dividing resistors. The rapid transient response and small transient voltage can be obtained when the load current changes. The proposed converter is fabricated with TSMC $0.18~\mu \text{m}$ 1P6M process. The switching frequency is 3 MHz. The total area of the chip is 1.44 mm² (with PADs). The measured results are as follows. When the load current varies between 50 mA and 500 mA, the fastest recovery time is only $1.6 ~\mu \text{s}$ , and the overshoot and undershoot are both 20 mV. The maximum efficiency is 90.1%.