Self-image-guided ultrasonic transceiver design for reliably powering mm-sized implants

This paper presents the design of a self-image-guided ultrasonic (SIG-US) transceiver for reliable wireless power transmission (WPT) to miniaturized biomedical implants. In the receiver (RX) mode, this paper proposes a method for high precision time interval measurement (TIM) between two signals independent of their amplitudes. In the transmitter (TX) mode, a 15 V Class-DE driver by stacking 3.3 V transistors of 180 nm standard CMOS technology is designed to drive a 32-element linear array. The designed TX efficiency is 90.93%. The post-layout and the Matlab k-Wave toolbox simulation results show that the designed system is capable of transmitting power to the implant with less than 0.9% reduction compared to the ideal SIG-US system over the ±45° steering range. Considering the mismatch effect between transistors, the power reduction is less than 2% in the worst case. The RX with a power consumption of 628.83 μW from a nominal supply voltage of 1.8 V, is capable of detecting time delays between two signals over the input range of 1 mV to 10 mV, with high accuracy.