9.8 A 50W 98%-Efficiency High-Power Wireless-Charging System with an Acoustic Noise-Reduced Ask Modulation Technique and Internal Hybrid Voltage-/Current-Mode ASK Demodulation

The near-field wireless charging system has become widely commercialized in mobile devices. The well-known and widely used Qi wireless power transfer (WPT) standard has been extended to version 2.0, now incorporating the magnetic power profile (MPP) standard in addition to the baseline power profile (BPP) and extended power profile (EPP). Figure 9.8.1 illustrates the communication between TRX, the trends in Qi wireless charging, and the basic concepts of amplitude shift keying (ASK) and frequency shift keying (FSK). The Qi standard is now expected to support high-power wireless charging exceeding 25W, which requires frequent and accurate TRX communication to ensure safety and maintain high signal quality.