Capacitor exchange method for improving DNL (Differential Nonlinearity)/INL (Integral Nonlinearity) of successive approximation analog to digital converter

Abstract

The invention discloses a capacitor exchange method for improving the DNL (Differential Nonlinearity) / INL (Integral Nonlinearity) of a successive approximation analog to digital converter (ADC), and relates to the fields of microelectronics and solid-state electronics, in particular to the field of high-performance ADCs. The DNL / INL error caused by judgment of a secondary high order can be offset by exchange of a secondary high-order capacitor with all subsequent capacitors between two conversions without introduction of any extra ADC, introduction of any correction algorithm or splitting of any capacitor. Compared with a conventional correction method for improving the DNL / INL with dependence on an auxiliary ADC, a correction algorithm or capacitor splitting, the capacitor exchange method has the effects of simpler structure, smaller chip occupation area and higher easiness in on-chip implementation.

Description

technical field [0001] The invention relates to the field of microelectronics and solid state electronics, especially the field of high-performance analog-to-digital converters. Background technique [0002] The ADC converts the analog signal into a digital signal, which is a process of anti-aliasing filtering, sampling, holding and encoding. The analog signal passes through the anti-aliasing filter and the sample-and-hold circuit, and first becomes a ladder-shaped signal, and then passes through the encoder to convert each level in the ladder-shaped signal into a corresponding binary code. Its working principle is as follows: figure 1 As shown, among them, the anti-aliasing filter filters out the out-of-band signal in the input signal to prevent it from being mixed into the effective bandwidth, the sample-and-hold circuit samples the continuous signal to discretize the continuous signal, and the quantization circuit converts the discrete sample The signal is converted into...

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