A Wide-Input-Range Ultrasonic Power Regulator with an Adaptive Voltage Generator for Implantable Applications

Ultrasonic power transmission provides an attractive solution to minimize the size of the implants while achieving high power levels (100 μW to several mW) required for most implant applications. Also, ultrasonic power transmission is affected by the distance and the alignment, and results in a wide input voltage range. A wide-input-range ultrasonic power regulator with an adaptive voltage generator for implantable applications is presented in this paper. A highfrequency voltage doubler circuit is used in the receiver to regulate the output voltage. On-chip capacitance is used to minimize the volume of the implant. The proposed regulator is designed in TSMC 0.18um CMOS process with 1.8 V supply voltage, and achieves a peak efficiency of 56.2%. The input voltage ranges from ±0.5 V to ±1.8 V.