An A/D interface based on σ Δ modulator for thermal vacuum sensor ASICs
An A/D interface based on σ Δ modulator for thermal vacuum sensor ASICs
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DOI：
10.1088/1674-4926/31/7/075008
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发表时间：
2010-07
影响因子：
5.1
通讯作者：
Li Jinfeng;Tang Zhen-an
中科院分区：
文献类型：
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作者：
Li Jinfeng;Tang Zhen-an
提出了一种新的用于热真空传感器asic的σ Δ调制器结构。采用表面微加工技术制作的微热板式热真空传感器可以检测1 ~ 105 Pa的气体压力。放大后的传感器差分输出电压信号馈入σ Δ调制器转换为数字域。所提出的σ Δ调制器利用前馈路径抑制谐波畸变并获得高线性度。与已有的前馈结构相比，该结构在电路复杂度、芯片面积和功耗方面均有显著降低。在第一积分器中引入了相关双采样技术来降低闪烁噪声。测量结果表明，在4 MHz采样率下，该调制器在7.8 kHz带宽下的SNDR为79.7 dB， DR为80 dB。该电路采用0.5 μm 2P3M标准CMOS技术制造。它占地面积为5 mm2，从单个3v电源消耗9mw。调制器的性能满足所考虑的应用要求。
A new σ Δ modulator architecture for thermal vacuum sensor ASICs is proposed. The micro-hotplate thermal vacuum sensor fabricated by surface-micromachining technology can detect the gas pressure from 1 to 105 Pa. The amplified differential output voltage signal of the sensor feeds to the σ Δ modulator to be converted into digital domain. The presented σ Δ modulator makes use of a feed-forward path to suppress the harmonic distortions and attain high linearity. Compared with other feed-forward architectures presented before, the circuit complexity, chip area and power dissipation of the proposed architecture are significantly decreased. The correlated double sampling technique is introduced in the 1st integrator to reduce the flicker noise. The measurement results demonstrate that the modulator achieves an SNDR of 79.7 dB and a DR of 80 dB over a bandwidth of 7.8 kHz at a sampling rate of 4 MHz. The circuit has been fabricated in a 0.5 μm 2P3M standard CMOS technology. It occupies an area of 5 mm2 and dissipates 9 mW from a single 3 V power supply. The performance of the modulator meets the requirements of the considered application.