DDR Signal Phase Alignment to Reduce SSN
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Solution Overview
Problem
Current methods for reducing simultaneous switching noise (SSN) in DDR interfaces are ineffective, as they either do not significantly decrease noise or complicate board design and signal transmission.
Innovation Solution
A signal processing method that determines the phase status of data synchronization signals and to-be-sent data signals, performing phase change processing such as polarity reversal on these signals to reduce coupling crosstalk and SSN, without increasing design complexity or affecting signal transmission.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Object-affected harmful factors
If inductive coupling crosstalk between signals is suppressed by decreasing I/O drive current, then SSN is reduced, but signal edge rate is affected and signal sequence is delayed
Solution Approach 1:
The patent changes the phase parameter of data signals dynamically. By detecting phase differences between data signals and reference signals, the system performs polarity reversal on specific data signals to align their phases, thereby reducing inductive coupling crosstalk and SSN without decreasing I/O drive current, thus maintaining signal edge rate and sequence integrity
2Object-affected harmful factors
If power source and ground pins of chip are increased to reduce SSN, then SSN is decreased, but board design and production difficulty increases
Solution Approach 1:
Instead of increasing physical pins, the patent changes the electrical phase parameter of signals through detection and polarity reversal operations. This software-controlled phase alignment approach reduces SSN without adding physical components or complicating board design and production
3Object-affected harmful factors
If I/O quantity is increased to reduce SSN, then SSN is decreased, but device complexity and design difficulty increases
Solution Approach 1:
The patent uses phase parameter modification through polarity reversal on existing I/O lines rather than increasing I/O quantity. By detecting phase differences and performing conditional polarity reversal, the system reduces SSN using the same physical I/O resources, avoiding increased device complexity
Data Source
AI summary
A signal processing method and apparatus. According to the signal processing method, phase change processing can be performed on to-be-sent data signals according to a phase status of a data synchronization signal and phase statuses of the to-be-sent data signals, so that phase differences between a majority of to-be-sent data signals in the processed to-be-sent data signals and the data synchronization signal meet a certain condition, thereby reducing a volume of coupling crosstalk, generated by the to-be-sent data signals, on the data synchronization signal and further reducing impact of simultaneously switching noise (SSN) on a system.