The idea of wireless power-transmission has a very modern almost futuristic feel to it but its origins date back over 130 years to the "War of Currents," which was an electrical distribution battle waged between Thomas Edison and George Westinghouse in the late 1880s.
However the person who really fueled the conflagration was the Serbian-American engineer and physicist Nikola Tesla (1856-1943) who made his name with dozens of breakthroughs in the production, transmission and application of electric power. Tesla is best known for his contributions to the design of the modern alternating current (AC) electricity supply system.
As a student in 1875, Tesla attended the Austrian Polytechnic in Graz, Austria. Ten years later, having immigrated to the USA, Tesla went to work for Edison and undertook the task of completely redesigning the Edison Company's direct current (DC) generators. He completed the task within months but when Edison reneged on his payment commitments Telsa resigned and quickly found employment with Edison’s great rival Westinghouse.
One of the things Tesla developed was an induction motor that ran on alternating current, a power system format that was becoming popular due to its advantages in long distance high voltage transmission. This was perfect for Westinghouse who had been trying to secure patents for a viable AC motor for years. With Westinghouse now licensing the induction motor a line had been drawn in the sand with Tesla now firmly on the opposite side of the "War of Currents”, from his former employer Edison.
What started out as a friendly competition between rival lighting systems developed into a full scale conflict whose prize was to light the 1983 World Columbian Exposition. As the ‘ARMs race’ grew, costs spiraled out of control with patents and engineers being consumed in huge quantities. The battle eventually cost Edison control of his own company which was merged into the conglomerate General Electric.
Ultimately it was George Westinghouse who won the bid to light the 1893 World's Columbian Exposition in Chicago and one of the star attractions was the "Tesla Polyphase System" where Tesla himself dazzled the astonished crowds by using high-voltage, high-frequency alternating current to wirelessly light a lamp on the opposite side of the room.
Sadly, despite having sold his AC electricity patents, Tesla died impoverished and in debt. His close friend the writer Mark Twain described Tesla's induction motor invention as "the most valuable patent since the telephone’.
Over a century later the battle for dominance in wireless charging technology continues and a new war of currents has started. If remote charging is to be adopted on a grand scale then the devices will need to be interoperable and that means establishing industry standards.
So far three consumer standards have emerged. The first is Qi which operates up to five watts, combines resonance and induction techologies and is perfect for charging mobile phones. Qi’s main competitor takes the form of Power Matters Alliance (PMA) who recently merged with the third standard created by the Alliance for Wireless Power (A4WP) which allows for higher power levels. PMA has traditionally played heavily in the fast-food market with a rapidly expanding presence in branches of Starbucks and McDonalds. However the A4WP standard could soon emerge as the dominant force since it is seeing a significant adoption rate by tablet and laptop computer manufacturers.
ON Semiconductor joined the A4WP in 2013 and since then, we have been active in contributing to the standard as well as in hosting A4WP events.
To learn more, view an ON Semiconductor webcast that provides an overview of the wireless charging market, including past, current and future technology trends, and discusses the market standards.