ADC Frontend Feed-Forward Error Cancellation for High-Speed Accuracy
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Solution Overview
Problem
Traditional analog frontend architectures in CMOS processes suffer from noise, signal distortion, and reduced system performance, particularly when dealing with higher frequency signals and higher throughput ADCs, due to errors introduced by the FDA.
Innovation Solution
A circuit design incorporating two signal pathways - an input signal path and a feed-forward signal path - with error cancellation circuitry that measures and corrects the error voltage introduced by the input amplifier, using a feed-forward active component and error cancellation circuitry to cancel the error voltage from the output signal.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If a traditional FDA architecture is used to drive an ADC, then the system can process high frequency signals with high throughput, but noise and signal distortion are introduced by the FDA, degrading output accuracy and system performance
Solution Approach 1:
The patent divides the signal path into two separate pathways: a main amplifier path that processes the input signal, and an auxiliary path that measures the error voltage from the amplifier. This segmentation allows independent optimization of each path - the main path maintains high throughput while the auxiliary path captures error information for correction.
Solution Approach 2:
The patent implements a feed-forward error correction mechanism where the error voltage measured in the auxiliary path is fed forward to the output path. The corrected output is generated by combining the main amplifier output with the inverted error signal, effectively canceling out the amplifier's noise and distortion components.
2Speed
If the FDA introduces error voltage to enable high speed operation, then signal throughput increases, but the error voltage degrades the quality of the digitized output
Solution Approach 1:
The patent introduces an intermediary measurement mechanism - the auxiliary path with its own amplifier that measures the error voltage without interfering with the main signal path. This intermediary allows the system to quantify and subsequently correct the errors introduced by the main amplifier, maintaining both high speed operation and signal quality.
Solution Approach 2:
The patent converts the harmful error voltage introduced by the amplifier into a useful correction signal. By measuring the error voltage in the auxiliary path and feeding it forward in inverted form, the system transforms the amplifier's deficiencies into a corrective mechanism that actually improves output accuracy.
3Measurement precision
If error cancellation circuitry is added to remove amplifier errors, then output accuracy improves, but circuit complexity increases with additional amplifiers and signal paths
Solution Approach 1:
The patent merges the error measurement and correction functions into a unified feed-forward architecture. The auxiliary path measures error, the error is amplified and inverted, and then combined with the main output - all in a single integrated circuit structure that achieves high accuracy without requiring multiple separate correction stages.
Solution Approach 2:
The patent changes the operational parameters of the amplifiers - the main amplifier operates at high gain for speed, while the auxiliary amplifier is optimized for accurate error measurement. The feed-forward path uses controlled gain stages to scale the error signal appropriately before combining it with the main output, allowing each component to operate in its optimal parameter range.
Data Source
AI summary
The present disclosure provides a circuit which may be a drive system for an analog-to-digital converter (ADC), wherein the circuit measures the error from an amplifier within an auxiliary path and feeds-forward the error for correction in a main amplifier path. This results in a system with an output where the amplifier errors are removed from the output signal, thus, improving the overall system performance.