Parallel Data Interface Coding to Reduce DC and Switching Noise
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Solution Overview
Problem
Parallel data interface systems face noise issues due to parasitic inductance, which reduce voltage and time margins, limiting transmission rates and frequencies.
Innovation Solution
A method and apparatus that utilize balance coding and scrambling to randomize the distribution of bits in parallel data, minimizing DC noise and switching noise through encoding and decoding processes, including a coding lookup table unit and a selection unit to map and unmap data, and an output driver to sequentially output encoded data.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If single-ended parallel transmission is used for parallel data interface, then data transmission capability is improved, but noise (jitter, voltage noise, reference fluctuation) increases due to parasitic inductance
Solution Approach 1:
The patent applies DC balance encoding to transform the data signal parameters, ensuring that the number of '0' bits equals the number of '1' bits in each encoded group. This parameter transformation changes the signal characteristics to minimize DC component variations and reduce noise caused by parasitic inductance, while maintaining parallel transmission capability
2Reliability
If noise is reduced in parallel data interface, then voltage margin and time margin are improved, but transmission rate and frequency are limited
Solution Approach 1:
The patent applies DC balance encoding in advance to the data before transmission. By pre-balancing the DC components of the transmitted signals, the encoding reduces voltage fluctuations and noise during transmission, thereby improving voltage margin and time margin without limiting the transmission rate
3Object-affected harmful factors
If DC balance encoding is applied to reduce noise, then DC noise and switching noise are minimized, but device complexity increases
Solution Approach 1:
The patent segments the data transmission into fixed-size groups (e.g., 8-bit groups) and applies DC balance encoding to each group independently using lookup tables. This segmentation approach simplifies the encoding process by breaking down complex data streams into manageable units, reducing overall device complexity while effectively minimizing DC noise and switching noise
Data Source
AI summary
A semiconductor device may include a coding lookup table unit including a plurality of coding lookup tables each of which is selected by a respectively selection signal, and a selection unit configured to receive one of N-bit parallel data and extract respective encoded data corresponding to the selection signal and to which the N-bit parallel data is mapped from the coding lookup table unit, and encoded data and extract respective N-bit parallel data corresponding to the selection signal and to which the encoded data is mapped from the coding lookup table unit, wherein N is 2 or an integer greater than 2, and wherein the coding lookup tables respectively store a plurality of coded data patterns that respectively correspond to patterns of the N-bit parallel data and are random temporally and spatially.