Sub-kHz Clock Generation From Room Illumination on Standalone CMOS LSI Chips

Abstract

This study proposes a sub-kHz clock generator by the room light illumination designed on-chip CMOS LSI chips. It generates a clock from a flicker in room light by receiving on-chip integrated photovoltaic cell, and extracts by low-pass filters, a comparator, Schmidt trigger and D-flip-flop to shape to digital signal. The system implements two photovoltaic cells of a large cell for power generation and a small cell for photo-detection that enables standalone operations. The system was designed on 0.18 $\mu$m standard CMOS process, and both the simulation and experimental results validated the operation. By adding D-flip-flops at the output enables to modify the clock to $1/n$ values that expands the applications.

Keywords

• Analog LSI
• clock generation
• Internet of Things
• LED