A New Ultra-Fast-Response Low-Transient-Voltage Boost Converter Suitable for Low-Voltage Solar Cells in Wireless Sensor Networks

Abstract

In this article, a new ultra-fast-response low-transient-voltage boost converter suitable for low-voltage solar cells in wireless sensor networks is presented. The proposed converter not only achieves a faster transient response but also higher power conversion efficiency. With the current-feedback adaptive-controlled technique, the system can operate in the more fixed switching frequency without extra phase-locked-loop circuits. The proposed new rail-to-rail current sensing circuit, which produces the inductor current information to the controlled loop, not only increases the stability of the system but also improves the dynamic response. The addition of a zero-current detector (ZCD) prevents the reverse current as the converter operates at light load, which enhances the conversion efficiency, and ensures that the converter works stably in the discontinuous conduction mode (DCM). The proposed converter has been implemented with TSMC 0.18- <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">$ {\mu }\text{m}$ </tex-math></inline-formula> 1P6M CMOS processes and occupies an area of 1.19 mm <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">$\times1.2$ </tex-math></inline-formula> mm. The measured results show that the transient response is <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">$2 ~{\mu }\text{s}$ </tex-math></inline-formula> when the load current changes between 1 and 200 mA. The peak conversion efficiency is 92.3% under 140-mA load current. The maximum efficiency improvement is 14.8% at 5-mA load current. The major contributions of this article are listed in the following: 1) we proposed a new architecture of boost converters with improved current-feedback and adaptive-controlled techniques; 2) the proposed architecture has one current loop and one voltage loop to balance the output voltage and the output current; 3) the proposed boost converter has the characteristics of fast response time and low transient voltage; 4) we have designed, implemented, and measured the proposed converters; and 5) from the figure of merit (FOM) formula, the performance of the proposed boost converter is better than other recent works.