Pseudo Differential Interconnect for Common-Mode Noise Rejection
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Solution Overview
Problem
Conventional differential interconnection methods in CMOS integrated circuits require multiple transmission lines, leading to increased chip surface area and noise issues due to power supply voltage noise, while single-ended pseudo differential interconnection methods struggle with noise removal across longer distances.
Innovation Solution
A single-ended pseudo differential interconnection circuit and signaling method that compares neighboring data signals and a transmit signal to generate detection signals, using level detectors and exclusive OR gates to decode data while minimizing the impact of power and data common noise, utilizing a reference voltage generator to produce positive and negative reference voltages.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Object-affected harmful factors
If conventional differential interconnection is used, then common mode noise is reduced, but chip surface area increases due to requiring two transmission lines
Solution Approach 1:
The patent divides the differential signaling function into multiple single-ended signal lines, where each line carries a portion of the differential pair functionality. This segmentation allows noise reduction capabilities to be distributed across multiple lines while using only single-ended transmission infrastructure, thus reducing chip surface area while maintaining noise rejection.
Solution Approach 2:
The patent combines multiple single-ended signal lines to achieve differential-like noise rejection performance. By merging the functionality of multiple single-ended lines, the system attains common mode noise reduction without requiring traditional differential pairs, thereby optimizing chip area utilization.
2Area of stationary object
If single ended pseudo differential interconnection is used, then chip surface area is reduced, but noise removal capability deteriorates across longer distances
Solution Approach 1:
The patent introduces an intermediary encoding scheme that transforms data into a format resilient to noise accumulation over long single-ended transmission lines. This intermediary representation allows the receiver to reconstruct the original signal while rejecting noise, effectively extending the usable transmission distance without requiring differential pairs.
Solution Approach 2:
The patent implements feedback mechanisms where the transmitter and receiver exchange information about signal integrity and noise conditions. This feedback enables dynamic adjustment of signaling parameters to maintain noise rejection performance over varying transmission distances while using compact single-ended lines.
3Area of stationary object
If conventional single ended interconnection is used, then chip surface area is minimized, but data transmission reliability deteriorates due to voltage signal susceptibility
Solution Approach 1:
The patent changes the signaling parameters by using encoded voltage levels and transition-based encoding schemes that are less susceptible to noise and interference. This parameter transformation maintains compatibility with single-ended transmission lines while significantly improving data transmission reliability without increasing chip area.
Data Source
AI summary
A single ended pseudo differential signaling method may add a 1-bit signal to n-bit data if transmitting the n-bit data. Neighboring two signals among the 1-bit signal and data signals are compared to each other to generate detection signals.