A 70%-power transmission efficiency, 3.39 Mbps power and data telemetry over a single 13.56 MHz inductive link for biomedical implants

Abstract

The application of wireless power and data telemetry to implantable medical devices (IMDs) has grown dramatically in recent decades. Achieving a high data rate and high-power transmission efficiency (PTE) over the same inductive link remains challenging. This paper presents a power and data telemetry circuit over a single 13.56 MHz inductive link. On the transmitter (TX) side, a binary-phase-shift keying (BPSK) modulation based on a Class-E amplifier that features a high modulation rate and a high quality (Q)-factor is proposed. A digital-assisted phase-locked-loop (PLL) is proposed on the receiver (RX) side as a BPSK demodulator to handle the long settling process. The maximum data rate can be extended to 1/4 of the carrier frequency. The prototype has been fabricated with a 180 nm BCD (Bipolar-CMOS-DMOS) process. The measurement shows that up to 31.25 mW of power can be delivered simultaneously with 3.39-Mbps of data transmission, while a 2 x 10(-7) bit-error-rate (BER) can be ensured over a transmission distance of 5 mm. The peak PTE is 70%, whereas the RX energy efficiency is 183 pJ/bit. The results demonstrate the potential of the proposed techniques in applications to various biomedical implants with intensive bandwidth and energy efficiency requirements.