This article presents an adaptive zoom-capacitance-to-digital converter (CDC)-based CMOS humidity sensor. The humidity sensor is realized by means of two differential capacitors whose dielectrics are sensitive to humidity. The sensing capacitors are interfaced with a zoom CDC, which consists of a successive-approximation-register (SAR) analog-to-digital converter (ADC) and a 3rd-order delta–sigma modulator ( $\Delta \Sigma \text{M}$ ). The SAR ADC eliminates the influence of the baseline capacitance to reduce the input range of the $\Delta \Sigma \text{M}$ . To improve the energy efficiency of the CDC across the full input range, a power-aware floating inverter amplifier (FIA) array is proposed, which is configured based on the conversion results of the SAR logic. In addition, an adaptive range-shift (ARS) zoom CDC is proposed to: 1) resist off-chip parasitics and interference and 2) allow low redundancy and a more energy-efficient FIA-based comparator, thus reducing power consumption. The proposed CMOS humidity sensor is implemented in a 0.11- $\mu \text{m}$ CMOS process. Measurement results show a capacitance resolution of 17.9 aF and an effective number of bits (ENOB) of 14.0 within a conversion time of 1.01 ms. The proposed humidity sensor consumes 1.5 $\mu \text{W}$ of power and exhibits a 0.0094 % relative humidity (RH) resolution and a ±1.5 %RH peak-to-peak accuracy (3 $\sigma $ error of 5.5 %RH) among 12 chips from 20 to 85 %RH, and it achieves a figure of merit (FoM) of 0.135 pJ $\cdot $ %RH ² , which is more than six times better than the state of the art.

中文翻译：

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使用自适应范围位移变焦 CDC 和功率感知浮动逆变器放大器阵列的节能型 CMOS 湿度传感器

本文介绍了一种基于自适应缩放电容数字转换器 (CDC) 的 CMOS 湿度传感器。湿度传感器是通过两个差分电容器实现的，这些电容器的电介质对湿度很敏感。传感电容器与变焦 CDC 接口，后者由逐次逼近寄存器 (SAR) 模数转换器 (ADC) 和三阶 delta-sigma 调制器 ( $\Delta \Sigma \text{M}$ ）。SAR ADC 消除了基线电容的影响，降低了输入范围 $\Delta \Sigma \text{M}$ . 为了提高 CDC 在整个输入范围内的能效，提出了一种功率感知浮动反相放大器 (FIA) 阵列，该阵列基于 SAR 逻辑的转换结果进行配置。此外，提出了自适应范围偏移 (ARS) 变焦 CDC 以：1) 抵抗片外寄生效应和干扰，以及 2) 允许低冗余和更节能的基于 FIA 的比较器，从而降低功耗。建议的 CMOS 湿度传感器在 0.11- $\mu \text{m}$ CMOS工艺。测量结果显示，在 1.01 ms 的转换时间内，电容分辨率为 17.9 aF，有效位数 (ENOB) 为 14.0。建议的湿度传感器消耗 1.5 $\mu \text{W}$ 功率并具有 0.0094 % 的相对湿度 (RH) 分辨率和 ±1.5 % RH 峰峰值精度 (3 $\西格玛 $ 5.5 %RH) 在 20 至 85 %RH 的 12 个芯片之间的误差，并实现了 0.135 pJ 的品质因数 (FoM) $\cdot $ %RH ² ，比现有技术好六倍以上。