Two-Stage ADC Residue Recombination for Accuracy and Low Power
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Solution Overview
Problem
Existing analog-to-digital converting apparatuses face challenges in achieving high accuracy and low power consumption while maintaining high speed and resolution, with open-loop converters reducing power consumption but degrading accuracy, and closed-loop converters consuming significant power and being slow.
Innovation Solution
The proposed solution involves a dual-stage analog-to-digital converting apparatus with a first stage converter performing initial conversion and a second stage delta-sigma converter, using a recombination logic circuit to combine output signals and feedback signals, allowing for high resolution and speed while optimizing power consumption.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Use of energy by moving object
If open-loop converters are used, then power consumption is reduced, but accuracy is degraded
Solution Approach 1:
The converter is divided into two stages: a first stage converter that performs initial conversion with lower power consumption, and a second stage delta-sigma converter that processes the residue signal to improve accuracy. This segmentation allows each stage to be optimized for its specific function, achieving overall high accuracy while maintaining low power consumption.
Solution Approach 2:
A residue signal is introduced as an intermediary between the first stage converter and the second stage delta-sigma converter. The residue signal carries the quantization error from the first stage, which is then processed by the second stage to achieve high accuracy without requiring the first stage to operate at high power consumption.
2Measurement precision
If closed-loop converters are used, then accuracy is improved, but power consumption increases and speed decreases
Solution Approach 1:
The system segments the conversion process into two stages with different architectures. The first stage uses an open-loop converter for fast, low-power initial conversion, while the second stage uses a delta-sigma converter to achieve high accuracy. This segmentation avoids the need for a single closed-loop system that would consume excessive power and operate slowly.
Solution Approach 2:
The first stage converter performs preliminary conversion of the input signal before the second stage processes the residue. This preliminary action removes the bulk of the conversion task from the second stage, allowing it to focus on achieving high accuracy with minimal power consumption rather than handling the entire conversion process.
3Measurement precision
If closed-loop converters are used, then accuracy is improved, but processing speed decreases
Solution Approach 1:
The conversion process is segmented into two stages with different speed characteristics. The first stage operates at high speed for initial conversion, while the second stage processes the residue signal at a slower pace to achieve high accuracy. The overall system achieves both high speed and high accuracy through this segmentation.
Solution Approach 2:
The first stage converter performs preliminary conversion at high speed, removing the time-consuming aspects of the conversion process. This allows the second stage to focus on accuracy-critical operations without compromising the overall processing speed of the system.
Data Source
AI summary
An analog-to-digital converting apparatus includes a first stage converter which performs a first analog-to-digital conversion on an input analog signal during a first stage period, a second stage converter which receives a first residue from the first stage converter amplified by a first gain and which performs a second analog-to-digital conversion during a second stage period, and a recombination logic circuit which combines a first output signal from the first stage converter and a second output signal from the second stage converter into an output digital signal that corresponds to the input analog signal. The second stage converter generates a second stage feedback signal obtained by amplifying the second output signal by the first gain during a first sub-cycle in the second stage period, and generates a second output signal of a second sub-cycle subsequent to the first sub-cycle based on the second stage feedback signal.