Wireless power transfer systems demand a regulating transmitter (TX)for global loop control and also a regulating receiver (RX) for its localloop. This design broadens the TX output power range, by merging aswitched capacitor (SC) circuit with only 3 switches and 1 flying ca-pacitor to boost the output power of the Class-D power amplifier. Inaddition, the transmitting power can be regulated by the duty ratio ofthe SC, improving the end-to-end power transfer efficiency under dif-ferent load conditions. Moreover, the system obtains fast load transientresponse, with the help of a light-to-heavy load transient enhancementscheme in the TX and the hysteretic control in the RX. Designed in a0.18-μm BCD process, this work achieves 3.1 W maximum RX outputpower, 67.6% peak total efficiency, and 50μs response time during thelight-to-heavy load transient simulation.