Adaptable Class-D Power Amplifier based Power Modulation and Data Transfer Technique for Biomedical Systems.

Class-D half and full-bridge power amplifiers (PA) finds their usefulness in wireless power transfer (WPT) blocks for a biomedical implant. This brief presents a 13.56-MHz wireless power transfer system using an adaptive PA structure and digital control scheme for providing sufficient power during downlink data transfer. This scheme prevents efficiency degradation due to amplitude modulation. Simultaneously changing PA structure and operating frequency gives a higher degree of freedom for power modulation. The transmitter and receiver sides were designed in the 0.18-μm CMOS process using 1.8 V and 5 V devices.