Non-Volatile Memory Reading Reference Current Automatic Regulation Circuit
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Solution Overview
Problem
The existing reading reference current regulation methods in non-volatile memory are inadequate in adapting to process threshold voltage deviations, leading to reading errors and reduced product yield due to outdated design simulations and manufacturing process fluctuations.
Innovation Solution
A reading reference current automatic regulation circuit that includes a main control module, reading check control module, readout result processing module, digital-to-analog conversion module, and signal switching module, which adaptively adjusts the internal reading reference current based on process threshold voltage deviations by performing traversal reading operations and adjusting the digital regulation signal bit by bit using a bisection method.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If the reading reference current is fixed based on design simulation, then the design process is simple, but the reading accuracy deteriorates due to process threshold voltage deviations
Solution Approach 1:
The patent implements a feedback mechanism where the reading check control module performs traversal reading operations on all memory addresses, compares readout results with expected values, and feeds back reading error signals to the reading reference current control module. This feedback loop enables automatic adjustment of the reading reference current based on actual process deviations, resolving the contradiction between simple fixed current design and accurate reading under process variations.
Solution Approach 2:
The system performs self-adjustment through automatic regulation. The reading reference current control module automatically adjusts the digital regulation signal based on reading error feedback, and the digital-to-analog conversion module converts the adjusted digital signal to analog reading reference current. This self-service mechanism eliminates the need for manual intervention while maintaining reading accuracy under process threshold voltage deviations.
2Ease of manufacture
If the reading reference current is adjusted manually based on outdated test data, then the system is simple to implement, but the product yield deteriorates due to inability to adapt to latest process deviations
Solution Approach 1:
The patent implements preliminary action by performing traversal reading operations and reading check before final product output. The reading check control module proactively tests all memory addresses with current reading reference current settings, identifies potential reading errors due to process deviations, and adjusts the reading reference current in advance. This preliminary detection and adjustment prevents defective products from being produced, thereby improving product yield while maintaining ease of manufacture through automated integration.
Solution Approach 2:
The system transitions from static manual adjustment to dynamic automatic regulation. The reading reference current is no longer fixed but dynamically adjusted based on real-time reading check results. The reading reference current control module continuously monitors reading accuracy and adapts the current settings according to actual process conditions, enabling the system to respond to latest process deviations and improve product yield.
3Reliability
If the reading reference current is increased to compensate for threshold voltage decay, then the reading reliability for aged memory improves, but the initial reading accuracy deteriorates due to current offset
Solution Approach 1:
The patent employs parameter changes by adjusting the reading reference current based on detected reading errors. The reading reference current control module modifies the digital regulation signal to change the reading reference current magnitude. Through iterative adjustment and reading check, the system finds the optimal reading reference current value that ensures reliable reading for aged memory without causing offset in initial reading accuracy, effectively resolving the contradiction between improved aged memory reliability and maintained initial reading precision.
Data Source
AI summary
The disclosure discloses a reading reference current automatic regulation circuit of a non-volatile memory. A reading check control module initiates a reading operation, a row reading operation is performed by controlling the memory to switch gate voltage of memory cells to bias gate voltage row by row, a comparison result between a memory cell readout value and an expected value is received, the reading check control module determines whether a reading check is passed according to the comparison result, a reading reference current control module adjusts the digital regulation signal according to whether the reading check is passed, and thus the magnitude of the reading reference current is adjusted through the digital-to-analog conversion module. The disclosure can adaptively regulate the internal reading reference current according to the process threshold voltage deviation in the test and meet the requirements on the function and reliability of the non-volatile memory.