Capacitive vs inductive power conversion
Semitrex has consolidated a fragmented industry by incorporating virtually every part necessary to make a power supply for circuits or chargers into one single module, vastly reducing the number of external parts. The company offers a muxcapacitor cascading technology that uses a capacitive rather than inductive conversions for the primary voltage reduction. According to the company, this new technology enables them to create a comprehensive power conversion breakthrough that produces the highest energy efficiencies and the lowest standby power draws. Later this year, the company will introduce a range of solutions based on its patented TRONIUM PSSoC. This cooler-running module requires <1 mW of standby power to stay ready to respond to the next current demand. Manufacturers can sign up to request samples for testing and evaluation. Find out more at www.semitrex.com.
A handbook on wireless power
Understanding the many challenges to designing an amplifier for wireless power, such as radiated EMI, multi-mode systems and ways to improve efficiency is the aim of the Wireless Power Handbook — A Supplement to GaN Transistors for Efficient Power Conversion. wireless power handbook, by Michael A. deRooij of Efficient Power Conversion Corp.
Since Nikola Tesla first experimented with wireless power, there has been a quest to “cut the cord” of electrical power — and go wireless! Now, over 100 years later, we finally have the technological capability to achieve Tesla’s vision.
Highly-resonant wireless power transfer, based on the generation of magnetic fields, has proven to be a viable path. Magnetic fields offer the necessary requisites — ease of use, robustness and, most importantly are considered safe.
A major challenge for implementing wireless power is the design of the amplifier. From experimental results presented in this book, it is clear that the ZVS Class D topology, fitted with eGaN power transistors provides the best solution. With their low capacitance, zero reverse recovery, and low on-resistance, eGaN FETs ensure low operating losses leading to higher amplifier efficiency and help keep EMI generation low. These devices have a very small footprint and low profile, which is important for mobile and medical applications.
Let’s face it, designing with GaN is a different animal from silicon, and you need to know how to get the right layout for the best results. This book provides timely information and provides an overview of wireless power transfer with observations on why you would want to create a wireless power design and sprinkles in some theory and challenges to understand before you get going. Also very helpful is a guide to select the best FET for your design. The experimental verification is sure to be helpful because you can learn from others how to find the right components and verify that they work for you. The author also supplies you with his experiences about things to look out for that may not be obvious, such as the conditions that can cause problems for the coil like multiple devices on the source or foreign objects on coil. Finally, there’s a healthy section on additional design considerations that help you design a product that is ready for the market.
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