一种提高SAR ADC的D/A转换精度的方法

A Method for Improving the D/A Conversion Precision of SAR ADC

为进一步提高R-C型SAR ADC的转换精度,在传统R-C型D/A转换结构的基础上,增加了一个偏移量模块,引入了小的偏移量。在采样过程中,当输入转换电压发生低于1个有效位的变化时,D/A转换结构能更精确地采样。该改进方法不改变传统电路的基本结构,只需增加很少的元件,就可改善ADC的精度和对零点采样的准确性。对10位R-C型SAR ADC进行了D/A转换和静态参数仿真。结果表明,INL、DNL均在±1LSB内,证明了改进方法的有效性。该方法可适用于其他位的R-C型D/A采样网络。

In order to further improve the conversion accuracy of R-C type SAR ADC,an offset module was added,and a small offset was introduced to the input in the sampling section based on the basic structure of traditional R-Ctype D/A networks.The D/A network could have better sampling performance when the input conversion voltage occurred below a significant bit change.The accuracy of the sampling of the zero point could be improved with only increasing necessary components and no changing the basic structure of the original circuit.The D/A conversion and the static parameters of the 10-bit R-Ctype SAR ADC was simulated.The results showed that the INL and DNL were both within±1LSB.So the results had verified the effectiveness of the proposed method. The method had translatability and could be applied to other R-Ctype D/A networks with different bit.