Category: Wireless Power Transfer

Powermat CEO calls wireless charging a ‘standard feature in the next iPhone’

Wireless charging is widely expected to be on one if not all new iPhone models later this year, and the CEO of a prominent wireless charging technology company appears to consider it a done deal. Powermat CEO Elad Dubzinski called wireless charging ‘a standard feature in the next iPhone’ ahead of any official iPhone 7s or iPhone 8 announcement. Powermat CEO calls wireless charging a ‘standard feature in the next iPhone’  

AW4PとPMAが統合しAirfuel Allianceを発足(2015年9月)

  最近、Rezenceに対するニュースが出ないことに気づき、いろいろ調べて見たら磁場共鳴を推進していた2つの団体が統合されていることがわかりました。半年以上前ですね。 いつも思いますが、ネーミングセンスが悪いですね。 競合相手のWPT と比較してみてください。: Wireless Power Transfer   A4WP : Alliance For Wireless Power PMA : Power Matters Alliance Merged wireless charging groups A4WP and PMA rebrand as AirFuel Alliance Following their announcement earlier this year to merge, the Alliance For Wireless Power (A4WP) and Power Matters Alliance (PMA) rebranded to the AirFuel Alliance on Tuesday. The new name signifies the two groups effort to work together for a more unified smartphone and tablet wireless charging solution. The two groups were separate over a number of years and together face a formidable competitor in the Wireless Power Consortium (WPC), which offers the popular Qi wireless charging standard used in […]

Evaluation of the DC-DC buck converter

  This is the evaluation reports of various DC-DC converter products that are available in Japan. DC-DC converter is used to provide a stable output DC voltage to its load such as rechargeable battery. We have tested 5 types DC-DC converter samples which is available in Amazon and Ebay. Thanks.   DC-DC-Converter Evaluation Report from Seong-Hun Choe

Competing wireless power standards: Qi vs. Rezence Competing Wireless Power Standards: Qi vs. Rezence By Noah Imam, Inteleaf, for Mouser Electronics Having to charge multiple devices can be frustrating. Whether it’s at an airport terminal or a coffee shop, power outlets can be a contentious commodity. Imagine if you could charge your device simply by setting it down. No more wires, dongles, or bulky chargers. With wireless charging technology, that’s likely to become commonplace. Today, the average person may have a phone, laptop, tablet, and a smartwatch, which are all steadily losing battery power and waiting to be recharged. According to the Radicati mobile statistics report, there will be over 9 billion mobile devices in […]

EPC corporation : Wireless Power Transfer

EPC is the GaN FET supplier for the WPT Technology. It published very interesting videos on WPT system and its GaN amplifier system. Please enjoy the following videos!   eGaN Technolgy for Wireless Power Transfer 2. Application Demo: eGan Technology 3. Cut The Cord! Demonstration of the GaN Based Wireless Power 4. eGaN IC’s – Integrate for Even Higher Efficiency 5. eGaN FET Application: Wireless Power Transfer

Measuring Wireless Power Transfer Efficiency (1)

Transmission efficiency of the wireless power transfer (WPT) system can be measured with a vector network analyzer (VNWA). The following picture shows how we measured the transmission efficiency of this system. The yellow WPT coil in the left side is connected to the port 1 of VNWA, while the blue WPT coil in the right side is connected to the port 2 of VNWA. The resonant frequency of this system is set to be 14 MHz. Therefore, the frequency range in this measurement is between 1 MHz to 27 MHz. The following figure shows the equivalent circuit of this WPT coil. Each component’s values were calculated by analyzing the input […]

Impedance matching of the WPT coil

Hello, I will explain how I matched input impedance of the WPT coil to 50 Ohm. Please look at the following picture. You can see that SMA cable is directly connected with the feed coil. Let’s see the frequency characteristic properties of this WPT coil. Frequency range is between 1 MHz and 27 MHz. So the center frequency is 14 MHz (=0.5*(1+27) MHz) that is the resonant frequency of this WPT coil. In the following picture, Blue line shows S11 [dB], Pink line shows VSWR, Green line shows Re(Zin), Yellow line shows Im(Zin) and Red line shows the Smith chart of S11. We can easily find that the impedance is […]

Measuring Lumped Elements Values for WPT coil

Hello. I will explain how to measure and  decide  lumped elements values for WPT coil. Here is the WPT coil that I made for my experiments. The WPT coil consists of a resonant coil and a feed coil with SMA connector. The resonant coil is spiral and has parasitic capacitance between the spiral lines and this capacitance make this coil resonate at LC resonant frequency. The feed coil is a simple circular shape that is connected with SMA connector. Two coils are coupled with each other and the degree of coupling is expressed with mutual inductance M or coupling coefficient k. The equivalent circuit of this coil can be shown […]