Wireless power transfer (WPT) systems are increasingly favored for applications such as implantable devices and portable electronics. In these systems, local voltage regulation on the receiver (RX) side ensures a well-regulated output voltage (V out ) under varied loading and coupling conditions. Meanwhile, global power regulation on the transmitter (TX) side improves end-to-end (E2E) efficiency, especially at light loads. For global power regulation, backscattering using load-shift keying (LSK) techniques is commonly adopted [1–6]. However, methods in [1, 2] necessitate an extra sensing coil and a data demodulator including multiple off-chip components to recover mode-switching signal containing full duty-cycle information of the RX in the TX, increasing costs and leading to poor transient responses. A constant-idle-time control is proposed in [3] to eliminate most of the off-chip components except the sensing coil by transmitting just one edge of the mode-switching signal to deactivate the TX for a fixed off-time. Hence, V out is only regulated by an upper boundary, resulting in poor load regulation with limited output power. A phase-locked loop is further introduced in [4] to ensure an adaptive off-time for a fixed mode-switching frequency, yet it worsens load regulation. In [5], a fully-integrated wireless hysteretic control sends the entire duty cycle back to the TX for tight regulation of V out . However, the light-load efficiency is compromised due to an always-active power amplifier (PA) in the TX and an inefficient linear current-sink voltage regulator in the RX. Additionally, the unpredictable V out noise spectrum limits its utility. Lastly, the fully-integrated wireless phase-shift control technique proposed in [6] relies on detecting a phase shift between coil current and voltage, preventing the full deactivation of the PA and thus also degrading the light-load efficiency.