Successive approximation analog to digital converter

Abstract

The invention relates to the technical field of electronics, in particular to a high-accuracy successive approximation (SAR) analog to digital converter, and aims to solve the problem that the conversion accuracy of the SAR analog to digital converter is lowered when a conversion efficiency is higher in the prior art. The SAR analog to digital converter comprises a D / A (Digital to Analog) converter, an SAR logical control circuit and a comparator, wherein the D / A converter is used for acquiring an original reference signal, and sampling a comparison reference signal output to the comparator according to a digital output code of the SAR logical control circuit; and the D / A converter is used for determining sampling time of the comparison reference signal according to the digital output code. The sampling time of the comparison reference signal in a conversion process is prolonged when significant bits of a current digital output code are first few bits, so that influences caused by vibration during conversion of the comparison reference signal are avoided.

Description

technical field [0001] The present application relates to the field of electronic technology, in particular to a high-precision successive approximation analog-to-digital converter. Background technique [0002] The conventional structure of the existing successive approximation analog-to-digital converter (SARADC) is as follows: figure 1 As shown, it includes S / H (SamplINg / Hold, sample and hold) circuit 110, D / A (Digital / Analog, digital / analog) converter 120, SAR (Successive Approximation, successive approximation) logic control circuit 130 and comparator 140. Partial composition. [0003] Its working principle is: in any system clock cycle, the S / H circuit samples the input signal VIN, and then sends the collected signal to an input terminal of the comparator 140, and the D / A converter 120 obtains the original reference signal VREF , the SAR logic control circuit 130 first sets the most significant bit (MSB) of its digital output code to 1, and the D / A converter 120 outp...

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Problems solved by technology

[0005] The purpose of this application is to provide a successive approximation analog-to-digital converter to solve the problem that the conversion accuracy of the successive approximation analog-to-digital converter in the prior art decreases when the conversion rate is high

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