This paper introduces a low-power fully differential fixed window level-crossing analog-to-digital converter (LC-ADC) for wireless medical implantable devices. The LC-ADC could be an excellent candidate for low-power systems due to the reduction of sampling points for bio-potential signals. Different from existing fixed window LC-ADCs, which use a 1-bit DAC or scaler and two reference levels to move the input signal to the comparison window, a simplified scheme is proposed in which the DAC or scaler is removed and a single-reference level is used to create the comparison window. The proposed LC-ADC utilizes a single-reference comparator, which leads to a simplified implementation and significant reduction in power consumption and circuit area. In addition, using a single reference level and removing DAC, leads to a decrease in the complexity of the controlling logic. The proposed LC-ADC is simulated in 0.18$$$\mu$m CMOS technology. The simulation results achieve an effective number of bits (ENOB) of up to 6.5 bits with about 59–141 nW power consumption under 0.8$$V supply and input signal bandwidth from 5$$Hz to 4$$kHz.

本文介绍了一种用于无线医疗植入设备的低功耗全差分固定窗口电平交叉模数转换器（LC-ADC）。由于生物电势信号采样点的减少，LC-ADC 可能成为低功耗系统的绝佳候选者。与现有的固定窗口 LC-ADC 使用 1 位 DAC 或定标器和两个参考电平将输入信号移动到比较窗口不同，本文提出了一种简化方案，其中去除了 DAC 或定标器并使用单参考level 用于创建比较窗口。所提出的 LC-ADC 采用单参考比较器，从而简化了实现并显着减少了功耗和电路面积。此外，使用单一参考电平并去除DAC可以降低控制逻辑的复杂性。所提出的 LC-ADC 在 0.18 中进行仿真$$$\mu$m CMOS技术。仿真结果实现了高达 6.5 位的有效位数 (ENOB)，0.8 功耗下的功耗约为 59–141 nW$$V 电源和输入信号带宽从 5$$赫兹至 4$$千赫。