Wednesday, May 11, 2016 11:00 AM
Location: Nuremberg, Germany
eGaN® FET based 6.78 MHz Differential-Mode ZVS Class D AirFuel™ Class 4 Wireless Power Amplifier (Session D02)
Speakers: Michael de Rooij, Ph.D., Vice President of Applications, Yuanzhe Zhang, Ph.D., Director of Applications Engineering
The ongoing evolution of highly resonant wireless power solutions, enabled by eGaN FETs, continues in this paper where a 33 W capable AirFuel compatible Class 4  power amplifier is presented. As the wireless power levels and charge surface areas increase, so do the design challenges. A 10 W eGaN FET zero voltage switching (ZVS) class D amplifier has been demonstrated as being capable of driving the entire AirFuel Class 2  impedance range without additional circuitry . Unfortunately, given the large increase in impedance range for AirFuel Class 4 systems, this may no longer be possible. This paper delves into the many challenges faced to realize a Class 4 wireless power amplifier solution that include, device thermals, device voltage limits, device selection, impact of timing, and design of support circuitry on the performance of the amplifier and devices. An experimental system is tested and the results show that despite the higher current and power levels, eGaN FETs continue to make inroads into realizing highly resonant loosely coupled wireless power solutions.
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Sunday, June 26, 2016 3:30 PM
Location: Shanghai, China
10 W Multi-mode Capable Wireless Power Amplifier for Mobile Devices
Speaker: Michael de Rooij, Ph.D., Vice President of Applications
There are currently 3 wireless power standards for the mobile device market, namely; the Wireless Power Consortium (Qi) standard , the Power Matters Alliance (PMA) standard  and the Alliance for Wireless Power (A4WP) standard . Recently PMA and A4WP merged to become known as AirFuel™. The proliferation of wireless power products for mobile applications will lead to consumer confusion and hinder adoption of this technology. A simple eGaN®FET based single amplifier topology capable of operating to all of the mobile device wireless power standards is presented. It uses a modified ZVS class D amplifier topology capable of operating at both high (6.78 MHz) and low frequencies (100 kHz through 315 kHz). In addition, a specially designed source coil that can be used for all the wireless power standards will be discussed. The amplifier and source coil together allow for true multi-mode capable wireless power transfer that will be experimentally verified to the A4WP class 2 and Qi/PMA standards and is designed to efficiently deliver up to 10 W into the load.
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