(A) hybrid hysteretic reconfigurable 3-level Buck converter with fast load transient response

Abstract

This thesis presents a hybrid hysteretic reconfigurable 3-level buck converter with a fast load transient response. A reconfigurable 3-level mode operation is proposed to improve the load transient response without the voltage rating issue. The RC feedback network of the hybrid hysteretic control can be adjusted for the optimized transient response. Furthermore, a hysteresis-based quasi-self-balancing scheme, keeping the voltage across the flying capacitor at half the input voltage, is proposed to guarantee stable operation of the proposed converter. Implemented in a 55 nm CMOS, the proposed converter achieves a maximum efficiency of 95.1% for a 4.2 V input. For a load current step of 750 mA, the under/overshoot voltage and settling time are 62/60 mV and 2.48/2.32 μs, respectively. Compared to the conventional 3-level mode operation, the proposed technique improves the under/overshoot voltage and settling time by 2.21/2.22 and 1.78/1.69 times, respectively.