A 2.8 μs Response Time 95.1% Efficiency Hybrid Boost Converter With RHP Zero Elimination for Fast-Transient Applications

This article proposes a hybrid boost converter that eliminates the right-half-plane (RHP) zero. The proposed converter can be designed with a broad bandwidth up to a tenth of the switching frequency, such that the converter can attain fast transient response as a buck converter. Besides, it features a left-half-plane zero which helps simplify the compensation network. With only one switch to tolerate the output voltage, the proposed boost converter can achieve high efficiency. Meanwhile, the voltage conversion ratio (CR) of the proposed converter is identical to that of the conventional boost converter (CBC), thereby enabling a wide range of output voltage. The dc characteristics, the driver design, the transfer function derivation, the compensation design, and the current-limiting self-startup circuit are also discussed in this article. Measurement results demonstrate that a peak efficiency of 95.1% is obtained. Given an input voltage of 4.2 V and output voltage of 6 V, with step-up and step-down load current ranging from 50 to 500 mA in less than 160 ns, the settling time is merely
$2.8~{\mu }$
s.