一种应用于流水线ADC的自适应后台校正技术

An Adaptive Background Calibration Technique for Pipeline ADC

流水线模数转换器(Pipeline ADC)是一种应用广泛的模数转换器结构,可以同时实现高速和高精度性能。然而电路的非理想性严重制约着流水线ADC的性能。提出了一种自适应数字技术,通过使用低速但准确的ADC作为基准,与待校正的流水线ADC并联,并将两者的数字输出的差值送入数字自适应滤波器中进行处理,使流水线ADC的输出不断逼近低速但准确的ADC输出,从而达到数字校正的目的。仿真结果表明,这种方法可以有效去除包括电容失配、有限运放增益、运放失调在内的误差。

Pipeline ADC is widely used which can realize both high speed and high resolution.But nonidealities of circuits will limit the performance of pipeline ADCs.An adaptive digital technique is proposed,which uses a slow but accurate ADC as a reference in parallel and sends the difference of the outputs of two ADCs into a digital adaptive filter for processing.The output of the pipeline ADC will get close to that of the slow but accurate ADC.The simulation result shows that errors including capacitor mismatch,finite gain and bandwidth of op-amps,offset are eliminated through this technique.