Single-Inductor Dual-Input Dual-Output Battery-PV Hybrid System with 2-D Adaptive On-Time Control for Internet of Things

In this article, we present a single-inductor dual-input dual-output power converter with two-dimensional adaptive-on-time (2-D AOT) control for Internet of things (IoT) applications. The proposed system combines energy from a 0.55-0.7 V photovoltaic (PV) module with a non-rechargeable 1.4-V zinc-air battery to extend the battery life. The proposed converter employs the buck-boost mode and the buck mode for the PV module and the battery, respectively, to produce two output voltages for different loading currents. The proposed 2-D AOT technique not only reduces the output voltage ripple but also improves the dual-source conversion efficiency over a wide input voltage range. Moreover, the response time of the self-tracking zero-current detector can also be improved by the proposed 2-D AOT. We fabricated the test chip using 0.18- μ m technology in an area of 1.9×2.2 mm². The measurement results demonstrated a peak efficiency of 92.5% with an input voltage range of 0.55-1.4 V. The output voltage ripple was less than 2.3% VOUT under different input voltage ranges.