一种四阶Σ-Δ调制器的设计与实现

【摘要】 文章采用自上而下(TOP-DOWN)分析方法,对单环结构的四阶Σ-Δ调制器进行了系统设计与仿真,电路设计与仿真。在系统级提出了基于systemview的高层次建模,通过系统仿真确定了关键的电路参数和性能指标。并采用前馈的方法避免了运算放大器的非线性造成调制器失真。在电路结构级采用了全差分形式,利用开关电容电路。再配合互不重叠时钟的控制,构造出系统所需的开关电容积分器。并且采用截断(chopping)技术,减小实际电路中的闪烁噪声。更多还原

【Abstract】 In this paper, the TOP-DOWN analysis method is used in the design of the 4-th order single loop Σ-ΔA/D modulator. All of the system and the circuits are designed and simulated. In system-level, high-modeling method based on systemview is presented. Key parameters and performance of the circuit are determined by system-level simulation. In the same time, the feed-forward method avoids the distortion caused by the non-linearity of the amplifier. In circuit-level, the circuit structure is full-differential model. The useful integrator is formed through the switch capacitance circuit and the non-overlap clock, and the technology of chopping is used in the circuit design in order to reduce the flicker noise.更多还原