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Tim Lu

CEO NewEdge Technologies, Inc.

A digital demodulator design  for Qi

The communication quality is vital for the performance and reliability of Qi wireless charging systems. Qi adopts in-band communication systems, where protocol data is transferred on top of the power signal. This method greatly reduces the overall system cost compared with out-of-band communication systems, where a separate communication device, such as Bluetooth, is used on a different radio frequency.

For in-band systems, however, power signals have great impacts on the communications quality due to its power level, and high order harmonics. In addition, the data integrity is affected by the load condition, which is ever changing during the battery charging process.

A poor communication quality may result in interruptions and drop-outs for battery charging, which in turn will degrade the user experience. Therefore, it is important to have a robust demodulation design, which can sustain severe interference and interruptions from the power signal and the load. 

Digital demodulator is known to be able to achieve better performance than its analog counterpart. It also offers flexibilities in dealing with severe signal distortions. In this speech, we describe the channel conditions, various interference scenarios, and design challenges. Our design approach to combat these severe environment is then presented.


Tim has over 30 years of experience in various industries, from Telecommunications to Consumer Electronics. His expertise ranges from detailed system and device designs to strategic marketing to corporate management. Over the past 30 years, he has started a number of companies developing various products.

In early 2006, he co-founded Focaltech Systems based in Shenzhen China, He was instrumental in developing and promoting the touch sensor ICs, which resulted in the IPO in 2013. He then founded NewEdge Technologies, Inc., a company focusing on the wireless charging IC development based in Shanghai. This company has developed a full line of products based on Qi standards for both transmitter and receiver ICs, from low power to medium power.

Tim has a Bachelor’s degree from National Chiao Tung University in Taiwan in 1973. He also has a Ph.D. degree in Electrical Engineering from University of California, Berkeley, in 1983.