Asynchronous successive approximation analog-to-digital conversion circuit

Abstract

The invention provides an asynchronous successive approximation analog-to-digital conversion circuit comprising a sample hold circuit, an analog-to-digital conversion circuit, a first voltage comparing circuit, a first logic circuit and a pulse generating circuit, wherein the first voltage comparing circuit compares input signals in response to an effective level of a latch signal, and outputs a first logic level and a second logic level; the first logic circuit identifies a comparison result of the first voltage comparing circuit according to the first logic level and the second logic level in response of the effective level of an identification signal; the pulse generating circuit generates the latch signal and the identification signal, wherein the generation moments of the effective levels of the latch signal and the identification signal are independent from the first logic level and the second logic level. The asynchronous successive approximation analog-to-digital conversion circuit can eliminate the problem that the comparing circuit is incomplete caused by the metastable state problem of the comparing circuit, guarantee the precision of the asynchronous successive approximation analog-to-digital conversion circuit, and is easy to implement and low in cost.

Description

technical field [0001] The invention relates to the field of electronic technology, in particular to an asynchronous successive approximation analog-to-digital conversion circuit. Background technique [0002] Among direct analog-to-digital converters (ADC, Analog-to-Digital Converter), successive approximation analog-to-digital converters (SAR ADC, Successive Approximation Register Analog-to-Digital Converter) are more commonly used. Its conversion process is similar to weighing objects with a balance, and SARADC compares the input analog signal with different reference voltages multiple times, so that the converted digital quantity is numerically close to the input analog quantity successively. The reference voltage is usually Generated by a digital-to-analog converter (DAC, Digital-to-Analog Converter). Successive approximation analog-to-digital converters include synchronous and asynchronous, wherein a synchronous successive approximation analog-to-digital converter (SS...

AI Technical Summary

Problems solved by technology

[0004] However, the metastability problem of the comparison circuit will limit the application of asynchronous successive approximation ADC, which will affect its effective number of digits and other performance

Images