An Adaptive Dual-Mode HBC Transceiver for Medical and Entertainment Applications

Human body communication (HBC) is a low-power communication method using the human body as a medium for wearable and implantable devices. Existing systems support either Carrier-Based HBC (CB-HBC) with carrier modulation for noise immunity or Carrierless HBC (CL-HBC) with carrierfree signaling for simplicity and higher data rates, leading to separate transceiver (TRX) designs and limited flexibility. This work presents a unified TRX in TSMC 65 nm silicon supporting both modes with real-time adaptability. Key features include: (1) a reconfigurable transmitter (TX) switching between CB-HBC across 4 carrier frequencies (up to 21 MHz) and CL-HBC, (2) an adaptive receiver (RX) with 4 digitally controlled bias levels for mode-specific gain-bandwidth tuning, and (3) programmable data rates up to 2 Mbps in CB-HBC, and 5.25 Mbps in CL-HBC. Measurement results show an energy efficiency of $25 \mathrm{pJ} / \mathrm{bit}$ (CB-HBC) and $8.4 \mathrm{pJ} /$ bit (CL-HBC), power consumption of $50 \mu \mathbf{W}$ and $44 \mu \mathbf{W}$ respectively, bit error rate (BER) $\lt10^{-4}$ at a carrier-to-data rate ratio $\lt14$ for CB-HBC, and sensitivity of $\mathbf{- 9 1 ~ d B m}$ in a $\mathbf{0. 1 2} \mathrm{mm}^{2}$ area.