Applied to the pipeline - the two-stage structure of the successive approximation analog-to-digital converter

Abstract

The invention provides a novel two-level structure applied to a pipeline-successive approximation analog-digital converter. The structure comprises a first level successive approximation analog-digital converter and a second level successive approximation analog-digital converter, wherein the first level successive approximation analog-digital converter comprises a first DAC (Digital-to-Analog Converter) capacitor array, a first capacitance bottom plate level switch controller and a first comparator; the second level successive approximation analog-digital converter comprises a second DAC capacitor array, a second capacitance bottom plate level switch controller, a third capacitance bottom plate level switch controller and a second comparator. Compared with the traditional technology, the novel two-level structure applied to the pipeline-successive approximation analog-digital converter provided by the invention eliminates the restriction of the limited bandwidth and limited gain of an operational amplifier to the precision, speed and power consumption of the whole circuit; moreover, an improved MCS (Modulation and Coding Scheme) switch strategy does not need the extra built-up time, and the power consumption of a capacitance switch in a frequent switching process is reduced; compared with the existing MCS technology, the total capacitance of the novel two-level structure provided by the invention is reduced to a half, and the average power consumption of level switching of the whole capacitance bottom plate is reduced by 80.585%.

Description

technical field [0001] The invention relates to the field of analog integrated circuit design, in particular to a two-stage structure applied to pipeline-successive approximation analog-to-digital converters. Background technique [0002] With the widespread use of handheld electronic terminals, the demand for analog-to-digital converters (ADC) with medium resolution (8-12bit), medium speed (tens of M) and low power consumption is becoming stronger and stronger at this stage. Among all ADC structures, the PIPELINE structure is widely used for its high speed and high precision. [0003] PIPELINE ADC is mainly composed of residual gain circuit (MDAC) and sub-analog-to-digital converter (SUBADC). The operational amplifier is used in the MDAC circuit. The static power consumption of the operational amplifier is very large, which increases the power consumption of the entire ADC. At the same time, the structure of PIPELINE is particularly complicated. In contrast, the successiv...

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Problems solved by technology

[0004] The traditional pipeline-successive approximation analog-to-digital converter structure requires operational amplifiers to be amplified and transmitted as inter-stage signals. Limited by the limited gain of operational amplifiers and the matching accuracy of capacitors, the transmitted signals will have large errors. The use of operational amplifiers Not only does it increase power consumption, the required settling time slows down the speed of the entire ADC, and the accuracy is also greatly affected

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