Integrated Circuit for Low-Frequency Sensor Signal Processing with Natural-Energy Power Supply

为了与电源电压小于1V的便携式设备无线通信测量生物信号，研制了一种低频信号处理集成电路。首先，针对所提出的低电压、低功耗的滤波器结构适合于基带信号处理的特点，设计了噪声抑制、带宽限制和基带调制的滤波器。即使采用0.18-μm工艺处理传感器信号，也能得到一个实用的0.6-V滤波器，动态范围可达89-dB。其次，考虑了带限滤波后的模数转换器(ADC)。研究了基于逐次逼近(SA)、ΔΣ和信号分解的流水线结构类型在低频和低电压下的应用。对它们的噪声性能进行了详细的理论分析，并提出了通过改变两者的浪费结构来提高信噪比的技术。最后，对数字基板噪声进行了处理。考虑了对多种噪声源的有效性，引入了一个可靠的简单模型，定量地讨论了噪声在三维体中的传播，得到了两种有效抑制衬底噪声的拓扑结构。综上所述，我们确信目标基带信号处理可以在小于0.8V的电压下实现。

An integrated circuit for low-frequency signal processing is developed to measure biological signals through wireless communication with portable equipments which are powered by energy source, the supply voltage of which is less than 1 V. First, filters for noise suppression, band limitation and baseband modulation are designed aiming at the point that the low-voltage and low-power filter structure which we have proposed is appropriate for baseband signal processing. A practical 0.6-V filter processing sensor signals is obtained even with 0.18-μm technology to achieve 89-dB dynamic range. Second, analog-to-digital converters (ADCs) following band limitation filters are considered. Successive approximation (SA),ΔΣ, and signal decomposition based pipeline types of architectures are investigated for low frequency and low voltage. Their noise performances are theoretically analyzed in detail and some techniques to enlarge signal-to-noise ratio by changing both wasteful structure are proposed. Last, digital substrate noise is coped with. Effectiveness with respect to a lot of noise sources are taken into account and a reliable simple model is introduced so that noise propagation in 3-D bulk is quantitatively discussed and 2 topologies effective for substrate noise suppression are derived. In conclusion, we are now sure that the aimed baseband signal processing is realizable with less than 0.8V.