An Illumination aware single solar-cell VCO CCO based Charge-pump energy harvesting system for SoC integration

R P, Kartheek (2016) An Illumination aware single solar-cell VCO CCO based Charge-pump energy harvesting system for SoC integration. Masters thesis, Indian Institute of Technology Hyderabad.

Text
EE14MTECH01006.pdf - Submitted Version
Restricted to Registered users only until 17 March 2020.
Download (4MB) | Request a copy

Abstract

A complete system for entire single solar-cell illumination range fully on-chip micro-scale energy harvesting is proposed. To maximize the extracted output power over the entire illumination range, optimal frequency operation and reconfigurable adaptive switch sizing techniques have been discussed. A fully digital illumination change detection block and a reconfigurable VCO/CCO (Voltage/Current Controlled Oscillator) scheme have been introduced. The proposed system has been designed in UMC 0.18-μm CMOS technology and the techniques used here offer an efficiency improvement up to 10% in both low, high illumination ranges compared to the conventional system and achieve a peak system efficiency of 67%. The objective of this system is to make energy harvester unit to drive wide range of ultra-low power applications by overcoming the challenges faced in conventional energy harvesting systems. Here, the proposed system is validated by driving ZigBee transceiver modelled electrically which consumes 200uW at supply voltage of 0.8V is driven in mid, high range solar illumination and acts as charger in low range solar illumination. Also, cold start-up circuit architectures based on nakagome voltage doubler, hybrid energy scavenging, four phase boot strapped charge pump regulator integrated with start-up scheme are designed and thorough performance comparision is presented. Finally, the most efficient solar, RF hybrid nakagome charge-pump based start-up system is layedout and post layout simulations are completed achieving the maximum efficiency of 39.64% in start-up mode. A Board level design of practical real time setup of self- powered energy harvesting system that can establish voice communication calls using zigbee transceivers is also completed pointing out the issues faced by all the commercially available energy harvesting chipsets and have been overcome in the proposed full system design.

[error in script]

IITH Creators: