Design of a Low Power DC-DC Inductorless Step Up Converter for Energy Harvesting

This work presents the design and analysis of a fully integrated, inductorless DC-DC step-up converter, based on switched-capacitor techniques, targeting ultra-low-power intraoc-ular applications. The proposed architecture is adapted from the work of Shih and Otis [1], and introduces an auxiliary charge pump to improve overall efficiency. The main converter generates a regulated 1.2 V output from a low-voltage source (400 mV), using high-voltage clock signals provided by the auxiliary charge pump to enhance charge transfer. The entire control circuitry is powered by the converter itself and includes a start-up sequence based on a voltage reference and a comparator, enabling autonomous operation from ambient light. Key building blocks such as the reference current source, ring oscillator, and four-phase generator were implemented and validated in simulation. The converter can deliver up to (10 μA) and demonstrates suitability for self-powered biomedical systems.