Power Injection Compensation for M-PSK Modulation Achieving SWPDT in Medical Implants

Reliable communication and robust power supply are critical requirements for medical implants. However, the achievable data rates are constrained by the large time constant due to the system's high quality (Q) factor. Additionally, achieving high data rates through PSK modulation can significantly reduce the average transfer power to the implant during phase shifts. This paper introduces M-PSK modulation and power injection compensation to enhance data rates and ensure reliable power transfer during communication. A lead-lag phase detector is implemented to demodulate the received signal. In a benchtop experiment, the IPT system (Qp=78.4) transmitted a 32-bit data sequence at 222kbps at 6.667MHz with zero error. The compensation improves the average load power from 79.7% to 101.2% of the unmodulated value.