Optimal Design of a Low-Power, Phase-Switching Modulator for Implantable Medical Applications

Since first proposed in JSSC [1], phase-switching modulation has been proved to be a viable transmission scheme. In this paper, we explored the maximum data-rate of phase-switching modulation and proposed a modified quadrature oscillator with a self-bias circuit to isolate the disturbance in power supply and ground. Dividers and filter are also optimized to minimize parasitic resistor and capacitor. The prototype is fabricated in a 0.18 μm CMOS process, with an active chip area of about 0.13 mm *0.35 mm. The total power consumption of the modulator is only 2 mW with an energy efficiency of 80 pJ/Bit. This modulator has been successfully embedded in a direct-up conversion transmitter for medical application.

自首次在《固态电路杂志》（JSSC）[1]中被提出以来，相位切换调制已被证明是一种可行的传输方案。在本文中，我们探究了相位切换调制的最大数据速率，并提出了一种带有自偏置电路的改进型正交振荡器，以隔离电源和地的干扰。同时对分频器和滤波器也进行了优化，以使寄生电阻和电容最小化。该原型采用0.18μm CMOS工艺制造，有源芯片面积约为0.13mm×0.35mm。调制器的总功耗仅为2mW，能效为80pJ/比特。该调制器已成功嵌入用于医疗应用的直接上变频发射机中。