基于AZFA技术的高精度低功耗Σ-Δ调制器

High-Precision Low-Power Σ-Δ Modulator Based on AZFA Technology

为满足高精度Σ-Δ调制器在实际应用中对于低功耗日益严格的要求,提出一种基于自稳零和双通道动态运放结合的AZFA技术的离散型Σ-Δ调制器。设计采用局部前馈、全局反馈的全差分二阶单bit量化结构,具有低功耗、低失调、低噪声、稳定性好的优点。整体电路采用SMICBCD 0.18μm工艺,工作电压为5 V。仿真结果表明,在过采样率(OSR)为512、采样时钟频率为163 kHz条件下,其信噪比、有效位数、整体功耗等相关指标均有优秀表现,适用于低速高精度低功耗系统的应用场景。

In order to meet the increasingly stringent requirements for low power consumption of high-precisionΣ-Δmodulators in practical applications,a discreteΣ-Δmodulator based on AZFA tech-nology combining auto zero(self-stabilizing)and dual-channel dynamic op amps is proposed.The fully differential second-order single-bit quantization structure of local feedforward and global feedback is adopted,and the modulator has the advantages of low power consumption,low offset,low noise and good stability.The whole circuit adopts SMICBCD 0.18μm process,and the working voltage is 5 V.The simu-lation results show that the design has excellent performance in terms of signal-to-noise ratio,effective number of bits,overall power consumption and other related indicators at the oversampling rate(OSR)of 512 and the sampling clock frequency of 163 kHz,which is suitable for the application scenarios of low-speed,high-precision and low-power systems.