Xiaosen Liu

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This paper presents a fully-integrated μW-level photovoltaic (PV) self-sustaining energy harvesting system proposed for smart nodes of Internet of Things (IOT) networks. A hysteresis regulation is designed to provide a constant 3.3 V output voltage for a host of applications, including powering sensors, signal processors, and wireless transmitters. Due to(More)
Implementing a monolithic highly efficient ultralow photovoltaic (PV) power harvesting system is pivotal for smart nodes of Internet of things (IOT) networks. This paper proposes a fully integrated harvesting system in 0.18-μm CMOS technology. Utilizing a small commercial solar cell of 2.5 cm2, the proposed system can provide 0–29 μW of power, which is much(More)
This paper presents a novel cost-effective automatic resonance tracking scheme with maximum power transfer (MPT) for piezoelectric transducers (PT). The conventional approaches compensate the PT with complex power factor correction schemes or drive it in resonance using intricate loops with limited operating range. The proposed tracking scheme is based on a(More)
Compared with inductive DC-DC boost converters [1], the charge pump (CP) features no off-chip inductors and is suitable for monolithic low power energy harvesting applications such as Internet of Things (IoT) smart nodes. However, the single conversion ratio (CR) CP has a narrow input voltage range. This induces a charge redistribution loss (CRL) and(More)
A monolithic microwatt-level charge pump energy harvester is proposed for smart nodes of Internet of Things (IOT) networks. Due to the variation of the available voltage and power in IOT scenarios, the charge pump was optimized by the proposed architecture and circuit level innovations. First, a reconfigurable charge pump is introduced to provide the hybrid(More)
A high-performance bootstrapped comparator operating with a single-polarity power supply is demonstrated for the development of GaN smart power ICs. The comparator features monolithically integrated enhancement-mode (E-mode) and depletion mode (D-mode) AlGaN/GaN HEMTs. The tail current source uses E-mode HEMT, enabling single-polarity power supply. The(More)
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