An Adaptive On-Off-Delay Compensation Scheme Based on Dead-Time and Rectified-Current Sampling for Ampere-Current-Level Series-Series Wireless Power Receivers

This article presents an adaptive on-off-delay compensation scheme for Ampere-current-level series-series (SS) wireless power receivers (RXs) to enhance both the power conversion efficiency (PCE) and the power delivering capability (PDC). The proposed off-delay compensation is realized by injecting an adaptive offset which is adjusted by sampling the rectified current. The proposed on-delay compensation is realized by inserting adaptive delays which are adjusted by sampling the dead time of the active full-wave rectifier. The proposed scheme was applied in a dual-mode resonant regulating rectifier which was fabricated in 0.18- $\mu $ m CMOS technology, and the regulated output voltage was set to 3.3 V. Measurement results demonstrated that the proposed scheme can effectively compensate for the on-off-delay as the RX input AC current varies from 0.7 to 2 A, corresponding to the coil distance varies from 26 to 42 mm. A measured peak PCE of 92.93% was achieved when the load current and coil distance were 0.945 A and 38 mm, respectively. Compared to the cases without delay compensation, the measured RX PDC increased from 495 mW to 1435.5 mW when the coil distance was 26 mm. Additionally, the measured PDC increased from 2557.5 mW to 4075.5 mW when the coil distance was 42 mm.