Efficiency Maximization for Device-to-Device Wireless Charging

Technology #18112

Questions about this technology? Ask a Technology Manager

Download Printable PDF

Professor Anantha Chandrakasan
Department of Electrical Engineering and Computer Science, MIT
External Link (www-mtl.mit.edu)
Nachiket Desai
Department of Electrical Engineering and Computer Science, MIT
External Link (web.mit.edu)
Managed By
Jack Turner
MIT Technology Licensing Officer
Patent Protection

Efficiency Maximization For Device-To-Device Wireless Charging

US Patent Pending US 2017-0040831

Efficiency Maximization For Device-To-Device Wireless Charging

PCT Patent Application WO 2017-023892
Rapid Wireless Capacitor Charging using a Multi-Tapped Inductively-Coupled Secondary Coil
Institue of Electrical and Electronic Engineers (IEEE) Transactions on Circuits and Systems I: Regular Papers 60, no. 9, September 2013, pp. 2263-72
Circuits and Systems for Efficient Portable-to-Portable Wireless Charging
MIT Masters Thesis, June 2014


Applications for this technology include small wireless devices such as smart watches, bluetooth headsets and mp3 players.

Problem Addressed

Modern developments in wearable electronics have resulted in minimized device sizes with greater functionality requirements. Because of minimal increases in battery life development, efficient methods of wireless battery charging is requisite. This technology presents an optimized wireless charging system, which reduces energy waste, thereby optimizing the user experience.


This invention presents a method for efficiently charging small electronics from larger devices such as a cell phone. The technology requires a transmission chip to be inserted into the larger device, as well as a receiver chip to be inserted into the small device. Once the devices are within each other’s proximity, the chips automatically detect each other’s presence and initiate the charging routine. A resonant rectifier design enables receiver-side energy management, and allows automatic optimization of the energy transmission based upon the particular battery parameters and charge state of the small device’s battery. This system continues to optimize the transmission flow rate as the small device’s battery charges. Once fully charged, the larger device automatically ends energy transmission saving energy and allowing for more recharging cycles.


  • Receiver-side energy management ensures consistent high efficiency wireless charging
  • Auto-detection of receiver eliminates wasteful energy transmissions
  • Minimal ionizing radiation makes this technology ideal for personal devices
  • Simple design assures reliability and low implementation costs