Compact GaN class-AB Armstrong oscillator for resonant wireless power transfer

Compact GaN class-AB Armstrong oscillator for resonant wireless power transfer

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In this study, a 4.4 MHz wireless power transfer (WPT) system was designed and implemented using a class-AB Armstrong oscillator that uses a packaged GaN on Si high electron mobility transistor. The oscillator is designed and simulated in advanced design system and then integrated with a magnetically coupled resonant WPT system. The transmitting planar coil of the WPT contains both the main and the feedback coils of the Armstrong oscillator. The whole system was implemented in a printed circuit board and tested. The DC-to-AC conversion efficiency of the simulated Armstrong oscillator is 69%. The maximum measured power transfer efficiency is 40.3% at a 2 cm distance between the transmitting and receiving coils. The input DC power of 37.5 mW provides 15.1 mW of AC power to the load with low distortion, making it suitable for low electromagnetic interference, size, power and cost applications such as biomedical implants.


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