Memory Controller Chien Search Tuning for ECC Power Reduction
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Solution Overview
Problem
The increase in storage capacity and integrity of semiconductor memory devices leads to higher error rates, which in turn increases power consumption due to the need for expanded error correction functions in memory controllers.
Innovation Solution
A memory system and method that adjust the cycle-per-power consumption of a Chien search unit by varying the number of bits searched and operation modes based on the number of errors in a read vector, allowing for reduced power consumption and optimized error correction time.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If error correction function is expanded to handle higher error rates from improved integrity and MLC, then error correction capability is improved, but power consumption increases
Solution Approach 1:
The patent implements dynamic adjustment of the Chien search unit's operation by varying the number of bits searched and operation modes based on the actual number of errors detected in the read vector. This dynamic adaptation allows the system to optimize power consumption while maintaining error correction capability, directly resolving the contradiction between reliability and power usage.
Solution Approach 2:
The patent changes operational parameters of the Chien search unit based on error conditions. Specifically, it adjusts the number of bits to be searched and the operation mode according to the estimated number of errors, thereby optimizing the balance between error correction performance and power consumption.
2Reliability
If the number of bits searched by the Chien search unit is increased to handle more errors, then error correction capability is improved, but cycle-per-power consumption increases
Solution Approach 1:
The system dynamically adjusts the search scope and operation mode of the Chien search unit based on the actual error count. When fewer errors are present, it reduces the number of bits searched, thereby improving cycle-per-power consumption while still maintaining adequate error correction capability.
Solution Approach 2:
The patent applies partial action by searching only the necessary number of bits corresponding to the actual error count rather than always performing a full search. This approach avoids excessive computation and optimizes the ratio of error correction capability to power consumption.
3Measurement precision
If the Chien search is performed on both data portions and parity portions of the read vector, then error detection accuracy is improved, but maximum correction time increases
Solution Approach 1:
The patent dynamically determines whether to perform Chien search on data portions, parity portions, or both, based on the estimated number of errors. This dynamic adjustment optimizes the balance between error detection accuracy and correction time by adapting the search scope to the actual error conditions.
Solution Approach 2:
The operation mode parameter of the Chien search unit is changed based on error conditions. The system selects different search scopes (data only, parity only, or both) according to the estimated error count, thereby optimizing both accuracy and time efficiency.
Data Source
AI summary
A controller to control a memory system including a memory device. The controlling the memory system may include calculating an error location polynomial in a received read vector with a key equation solving unit of the memory system to read data from the memory device, estimating the number of errors in the received read vector with a control unit of the memory system according to at least one of the calculated error location polynomial and information on the error location polynomial, searching error locations of the received read vector according to the calculated error location polynomial with a chien search unit of the memory system with the control unit. A cycle-per power consumption of the chien search unit may be adjusted with the control unit. A maximum correction time may be adjusted according to the number of errors of the read vector.