Pseudo-Differential Interconnect Using Adjacent Signal Comparison
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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 efficiency as the number of parallel DQ lines increases.
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 without being affected by power common noise and data common noise, thereby reducing noise impact.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Object-affected harmful factors
If conventional differential interconnection is used, then noise removal capability is improved, but chip surface area and device complexity increase due to requiring two transmission lines
Solution Approach 1:
The invention segments the differential signaling function into a pseudo-differential approach where only one transmission line is used. The data signal is segmented into multiple bits transmitted sequentially, and noise cancellation is achieved by comparing adjacent signal levels rather than using balanced differential pairs, thus eliminating the need for two transmission lines while maintaining noise rejection capability
Solution Approach 2:
The single transmission line in the pseudo-differential interconnection performs multiple functions: it transmits data signals, enables noise cancellation through adjacent level comparison, and eliminates the need for separate reference voltage lines. This multi-functionality allows the system to achieve differential signaling benefits with single-ended hardware
2Area of stationary object
If conventional single ended interconnection is used, then chip surface area is reduced, but noise removal capability deteriorates due to power supply voltage noise affecting the signal
Solution Approach 1:
The receiver uses feedback by comparing the current signal level with the previous signal level to detect transitions. This feedback mechanism allows the system to distinguish between actual data transitions and noise-induced variations, as noise typically does not produce consistent adjacent level differences, thereby enabling noise removal in single-ended signaling
Solution Approach 2:
The transmitter prepares the signal by establishing distinct adjacent voltage levels before transmission. The receiver is pre-configured to compare these adjacent levels, creating a preliminary reference framework that enables noise rejection at the reception stage without requiring additional hardware
3Productivity
If the number of parallel DQ lines is increased, then data transmission capacity is improved, but noise removal efficiency deteriorates as power common noise and data common noise affect multiple lines
Solution Approach 1:
The invention uses periodic action by transmitting multiple data bits in sequence over a single transmission line rather than simultaneously over multiple parallel lines. This sequential periodic transmission eliminates common noise affecting multiple lines at once, as each bit is transmitted and processed independently with adjacent level comparison, maintaining noise removal efficiency while achieving high data capacity
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.