Two-Phase Residue Amplification for Low-Offset Precision ADCs
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Existing analog-to-digital converters (ADCs) face challenges in achieving low-power, low-offset, and low-noise precision conversion due to imperfections in manufacturing and the need for auto-zeroing circuits, which increase noise levels and power consumption.
Innovation Solution
The development of an ADC circuit that incorporates an auto-zeroing residue amplification mechanism operating in two phases, where both observations of the amplified residue value are utilized to cancel out offsets, resulting in a higher signal-to-noise ratio and reduced power consumption.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If auto-zeroing circuits are used to reduce offset, then offset stability is improved, but noise level increases
Solution Approach 1:
The conversion process is divided into two distinct phases: a first conversion phase that produces a first digital code, and a second conversion phase that processes the residue. This segmentation allows the system to separate offset cancellation operations from signal processing operations, enabling offset reduction without proportionally increasing noise in the final output.
Solution Approach 2:
The ADC operates in periodic phases, alternating between first conversion phase and second conversion phase. During the first phase, the residue is amplified and converted to a first digital code. During the second phase, the residue is converted to a second digital code. This periodic operation allows systematic offset cancellation while managing noise contribution from each phase.
2Measurement precision
If auto-zeroing circuits are used to reduce offset, then offset stability is improved, but power consumption increases
Solution Approach 1:
The conversion process is divided into two distinct phases: a first conversion phase that produces a first digital code, and a second conversion phase that processes the residue. This segmentation allows the system to separate offset cancellation operations from signal processing operations, enabling offset reduction without proportionally increasing noise in the final output.
Solution Approach 2:
The system performs two conversions of the same residue signal, which is more than the single conversion traditionally required. This partial redundancy allows offset cancellation through comparison and combination of the two digital codes, achieving offset stability without requiring continuous high-power auto-zeroing circuitry that would consume excessive power.
3Measurement precision
If precision conversion is achieved, then measurement accuracy is improved, but device complexity increases
Solution Approach 1:
The same residue amplification circuit and residue-to-digital converter are used in both the first conversion phase and the second conversion phase. This multi-functionality allows the system to achieve precision conversion through repeated use of the same hardware blocks, avoiding the need for separate dedicated circuits for each conversion operation and thereby limiting the increase in device complexity.
Data Source
AI summary
Disclosed herein are some examples of analog-to-digital converters (ADCs) that can perform auto-zeroing with amplifying a signal for improvement of a signal-to-noise ratio. The ADCs may produce a first digital code to represent an analog input signal and a second digital code based on a residue from the first digital code, and may combine the first digital code and the second digital code to produce a digital output code to represent the analog input signal. The ADC may utilize a first observation and a second observation of an analog residue value representing the residue to produce the second digital code.