Extending battery life of smartphones by overcoming idle power consumption using ambient light energy harvesting

Abstract

Consumer electronic devices such as smartphones, tablets, and laptops typically require recharging once or twice a day and have limited battery life. Increasing adoption of and dependence on smartphones has led to consumers occasionally carrying conventional chargers, USBs, power packs, or solar chargers to sustain their devices throughout the day. These products are bulky, heavy, and expensive. New approaches are necessary to improve consumers' day-to-day experiences with charging their electronic devices. This paper explores the application of ambient light energy harvesting using a Gallium Arsenide (GaAs) solar cell to extend the battery life of smartphones. Different solar cell types, maximum power point tracking (MPPT) algorithms, and harvester ICs are analyzed in addition to smartphone user behavior model and standby/idle power consumption. Finally, the performance of a light energy harvesting system (EHS) using a GaAs solar cell and an ultra-low power energy harvester is compared for different indoor light sources. Maximum power of approximately 12 mW is produced indoors by the EHS for a smartphone-sized GaAs solar panel. For smartphones that consume 30 mW when idle, the GaAs solar panel can reduce the idle power consumption by almost half indoors, hence, doubling the time the device can be kept idle. Based on the results, practical benefits and challenges of such a system for various consumer electronic devices are discussed.