Chip Select Signal Training Using Split High-Low Pulse Sampling
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Solution Overview
Problem
Current chip select (CS) signal training methods in memory devices, particularly in high-speed DDR and LPDDR, face challenges such as increased complexity due to higher data rates and frequencies, leading to issues like inter-symbol interference, cross-talk, and voltage noise, with existing methods failing to accurately align CS signals with clock signals.
Innovation Solution
The implementation of enhanced CS signal training using multiple DQ pins to separately indicate results for high and low pulses of the CS signal, along with defined sampling windows and reduced clock frequencies for entry and exit, allowing precise alignment of CS signals with clock signals.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Speed
If chip select signal training is performed at higher data rates and frequencies, then data transfer speed is improved, but signal alignment accuracy deteriorates due to inter-symbol interference, cross-talk, and voltage noise
Solution Approach 1:
The patent segments the chip select signal training by separating high pulse sampling and low pulse sampling into distinct operations. Each pulse type is sampled independently during dedicated sampling windows, allowing the memory device to accurately evaluate each pulse's alignment with the clock signal without interference from the other pulse type. This segmentation enables precise alignment assessment even at higher data rates.
Solution Approach 2:
The patent implements preliminary action by performing sampling window operations before final signal alignment is achieved. The memory device samples the chip select signal during defined sampling windows that occur before the signal fully stabilizes, allowing iterative adjustment and refinement of alignment parameters. This preliminary sampling enables continuous optimization of signal alignment during the training process.
2Measurement precision
If multiple sampling operations are performed for chip select signal training, then alignment accuracy is improved, but training complexity and time consumption increase
Solution Approach 1:
The patent applies local quality by creating distinct sampling windows with specific timing characteristics for high pulse sampling and low pulse sampling. Each sampling window is locally optimized for its specific pulse type, with predetermined timing parameters that match the expected signal characteristics. This localized optimization simplifies the overall training process by providing clear, differentiated procedures for each sampling scenario rather than using a single complex universal approach.
3Device complexity
If chip select signal training is performed without separate sampling windows for high and low pulses, then training simplicity is maintained, but signal misalignment occurs in high-speed operations
Solution Approach 1:
The patent segments the sampling process into distinct high pulse sampling windows and low pulse sampling windows, each with predetermined timing parameters. This segmentation ensures that each pulse type is evaluated under optimized timing conditions, preventing misalignment while maintaining clear and manageable training procedures. The segmented approach provides reliability without excessive complexity.
Solution Approach 2:
The patent utilizes parameter changes by adjusting the timing parameters of sampling windows based on the specific pulse type (high or low). Different sampling windows have different timing characteristics optimized for their respective pulse types. This parameter adaptation enables accurate signal alignment at high speeds while keeping the training methodology simple and systematic.
Data Source
AI summary
In some aspects, an electronic device may receive a clock signal having a first frequency. The electronic device may receive, for a chip select training operation, a chip select signal having a pattern including high pulses and low pulses. The electronic device may perform, for a sampling window, the chip select training operation using the clock signal and the chip select signal, wherein the sampling window includes a quantity of pulses of the chip select signal. The electronic device may provide, via a first data in or out (DQ) pin, an indication of a first result of the chip select training operation for the high pulses of the chip select signal. The electronic device may provide, via a second DQ pin, an indication of a second result of the chip select training operation for the low pulses of the chip select signal. Numerous other aspects are described.