Non-volatile Memory Page Buffer ECC Decoding and De-randomizing
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Solution Overview
Problem
The increasing integration of semiconductor memory devices leads to a rise in defective memory cells and coupling interference, which decreases yield and performance, and existing error correction code (ECC) and randomization methods are inefficient, increasing read time and power consumption.
Innovation Solution
A non-volatile memory device with an on-chip ECC engine and randomization circuit that independently performs ECC decoding and de-randomizing, using seed values to reduce read time and power consumption by storing only correction bits in the page buffer circuit.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If ECC decoding and de-randomizing are performed sequentially in the conventional manner, then the operations can be completed, but the read time increases and power consumption increases
Solution Approach 1:
The patent segments the read operation into two independent parallel processes: ECC decoding process and de-randomizing process. The ECC decoding is performed on sensed data to generate decoded data, while simultaneously the de-randomizing is performed on the decoded data using seed values. This segmentation allows both operations to proceed concurrently rather than sequentially, reducing overall read time while maintaining ECC decoding accuracy.
Solution Approach 2:
The patent performs preliminary action by preparing seed values in advance and storing them in the page buffer circuit before they are needed for de-randomizing. The seed values corresponding to source pages are pre-loaded into the page buffer, enabling the de-randomizing operation to start immediately when ECC decoding completes, without waiting for seed value generation. This preliminary preparation reduces the overall read time.
2Reliability
If ECC decoding and de-randomizing are performed sequentially in the conventional manner, then the operations can be completed, but power consumption increases
Solution Approach 1:
The patent segments the read operation into two independent parallel processes: ECC decoding process and de-randomizing process. By performing these operations simultaneously rather than sequentially, the total operational time is reduced, which directly reduces power consumption. The page buffer circuit is efficiently utilized to store and manage both sensed data and seed values, enabling parallel processing without requiring additional buffer resources that would increase power consumption.
Solution Approach 2:
The patent ensures continuity of useful action by overlapping the ECC decoding and de-randomizing operations in time. While ECC decoding is being performed on sensed data, the de-randomizing operation simultaneously processes the decoded data using pre-loaded seed values. This continuous parallel processing maximizes the utilization of circuit resources and reduces idle time, thereby reducing overall power consumption while maintaining the reliability of ECC decoding.
3Reliability
If all decoded data are stored in the page buffer circuit, then data integrity is maintained, but the page buffer circuit size increases
Solution Approach 1:
The patent extracts only the essential seed values from the decoded data and stores them in the page buffer circuit, while the remaining decoded data are directly output without being stored in the buffer. The seed values are the critical elements needed for de-randomizing operations, so storing only these minimal necessary data maintains data integrity for the de-randomizing process while significantly reducing the page buffer circuit size and avoiding unnecessary buffer occupancy.
4Quantity of substance
If integration degree of semiconductor memory devices increases, then memory capacity increases, but the number of defective memory cells increases and coupling interference increases
Solution Approach 1:
The patent performs preliminary randomizing on data before writing to memory cells, and preliminary de-randomizing on read data before output. This preliminary action of randomization and de-randomization distributes and mitigates the effects of defective memory cells and coupling interference that increase with higher integration degrees. By applying error correction and randomization techniques in advance, the system compensates for the increased defects and interference, maintaining yield and reliability despite higher memory capacity.
Data Source
AI summary
A method of operating a non-volatile memory device, includes, storing sensed data in a page buffer circuit by sensing data stored in a source page of a memory cell array, outputting the sensed data from the page buffer circuit, performing error correction code (ECC) decoding of the sensed data output from the page buffer circuit, storing the decoded data in the page buffer circuit, and providing de-randomized data to an external device as read data by performing de-randomizing of the decoded data output from the page buffer circuit using seed values corresponding to the source page.