New Compact Solar Harvester to Reduce Size and Improve Harvesting Efficiency in Space-Constrained Wearable and IoT Devices

Published  January 12, 2021   0
MAX20361 Solar Harvester from Maxim Integrated

MAX20361 is a single-/multi-cell solar harvester with maximum power point tracking (MPPT) from Maxim Integrated. This new solution enables designers working on space-constrained wearable and IoT applications to increase runtime and reduce the solution size by half. With fewer, small-sized external components required, this fully integrated solar harvesting solution can reduce the size by at least 50 percent and at the same time can increase the harvested energy by up to 5 percent.          

The MPPT technique used in MAX20361 allows efficient harvesting from 15μW to over 300mW of available input power. The adaptive MPPT features coupled with the unique integrated harvesting gauge for real-time indications of efficiency can help achieve additional harvesting gains and optimize performance.

The device comes with an ultra-low quiescent current (360nA) boost converter that is capable of starting from input voltages as low as 225mV (typ). The MAX20361 also features an integrated charging and a protection circuit that is optimized for Li-ion batteries and can also be used to charge supercapacitors, thin-film batteries, or traditional capacitors. Besides, it features a programmable charging cut-off voltage with thresholds programmable through the I2C interface and temperature shutoff.

Key Features of MAX20361 Solar Harvester

  • Single-/Multi-Cell Solar Energy Harvester
  • 225mV to 2.5V (typ) Input-Voltage Range
  • Efficient harvesting from 15μW to over 300mW of available input power
  • 86% Efficiency at VSYS = 3.8V, ISRC = 30mA
  • Utilizes Small 2016 4.7μH Inductor
  • Maximum Power Point Tracking (MPPT) Technique using fractional VOC method
  • Programmable fractional VOC regulation point through the I2C interface
  • Programmable Battery Termination Voltage through I2C Interface
  • Programmable Power Good Wake-Up Signal Output Threshold through I2C Interface

The MAX20361 is available in a 12-bump, 0.4mm pitch, and 1.63 mm x 1.23 mm wafer-level package (WLP). It is available from the company website and from the authorized distributors for $2.64. The MAX20361EVKIT# evaluation kit is available for $57.