Compact and high-power bidirectional wireless power transfer (WPT) systems are desirable for mobile device-to-device (D2D) wireless fast charging. Prior WPT solutions [1]-[3] with integrated Class-D power amplifier (PA) provide relatively low output power (<10W). A Class-E PA has higher output power capability than a Class-D PA with the same input voltage. The 70W single-ended Class-E PA in [4] uses one additional bulky discrete MOSFET working as a tunable capacitor for impedance matching, achieving zero-voltage-switching (ZVS) and zero-voltage-derivative-switching (ZVDS) with 50% switching duty cycle across wide load and distance ranges. The 100W differential Class-E PA in [5] provides higher output power but requires a discrete impedance tuning network with 2 C_BLOCKprime s, 3R_DC primes, and 2 MOSFETs. These two solutions are well suited for pad-to-device wireless charging, but are hard to be embedded in a mobile phone. In addition, to regulate the PA output power, the supply voltage of the PA is tuned by a DC-DC converter in a conventional two-stage solution. In this work, we design a compact single-stage regulated Class-E architecture with adaptive ZVS control for D2D wireless fast charging.