改善开关电容型△-∑模数转换器采样精度的方法  

Methods of improving sampling accuracy of △-∑ ADC with switched-capacitors

作　　者：姜鹏[1] 徐科军[1,2] 

机构地区：[1]合肥工业大学电气与自动化工程学院,安徽合肥230009 [2]工业自动化安徽省工程技术研究中心,安徽合肥230009

出　　处：《电子设计工程》2010年第12期170-173,177,共5页Electronic Design Engineering

基　　金：国家863计划基金资助项目(2007AA04Z180)

摘　　要：以ADS1158为例,提出保证开关电容型△-∑模数转换器有效位数的方法。这些方法包括差分采样、输入滤波、减小驱动电路输出阻抗、采用差分输入差分输出放大电路、将ADC的地布在模拟地上、由同一基准源为传感器和ADC提供参考电压以及使用缓冲器。当ADS1158工作在15 KSPS/Channel、多通道循环模式下,常规的方法只能达到13位有效位数,而采用该设计方法实现了15位有效位数。有效改善了ADC的采样精度,能够在工业测量中应用。Taking ADS1158 as an example, several methods are presented to ensure the effective number of bits of △-∑ ADC with switched-capacitors in this paper. These methods include differential sampling, filtering input signal, reducing the output impedance of drive circuit, adopting the amplifier with differential input and differential output, placing the ground of the ADC on the analog ground, providing the same reference voltage for both sensor and the ADC, and using a buffer. When ADS1158 is configured for 15KSPS/Channel and multi-channel scan mode, ADC can only access 13 ENOB by the normal way while 15 ENOB by the presented methods. These methods can effectively improve the sampling accuracy of this type of ADC, and can be applied to industrial measurements.

关 键 词：开关电容 △-∑ ADC 有效位数 ADS1158 

分 类 号：TP274.2[自动化与计算机技术—检测技术与自动化装置]