I/O Buffer Offset Calibration Using Transition-Point Adjustment
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Solution Overview
Problem
Input or output buffer offsets in integrated circuit devices, such as NAND flash memory, lead to errors in setup and hold time requirements due to variabilities in fabrication and signal termination impedance, causing operational failures.
Innovation Solution
Applying specific voltage levels to the inputs of the I/O buffer until the logic level of the output transitions, and using calibration logic and circuitry to adjust the buffer offset by restricting or sourcing current, or adjusting resistances in the current paths to mitigate these offsets.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If standard I/O buffer design is used, then device complexity is reduced, but buffer offset errors occur due to fabrication variabilities and impedance imbalances
Solution Approach 1:
The patent applies preliminary calibration action by performing buffer offset measurement and correction before normal operation. The calibration circuitry measures the actual offset of the differential amplifier buffer and applies corrective voltage adjustments to compensate for fabrication variabilities and impedance imbalances, ensuring reliable buffer operation without requiring complex redesign of the standard buffer architecture.
Solution Approach 2:
The patent introduces calibration circuitry as an intermediary component that mediates between the standard I/O buffer and the external signals. This calibration circuitry includes offset measurement circuits and voltage adjustment mechanisms that act as intermediaries to correct buffer offset errors, allowing the standard buffer to operate reliably without fundamentally changing its simple structure.
2Ease of manufacture
If fabrication process is simplified, then manufacturing precision decreases, causing buffer offset variations
Solution Approach 1:
The patent implements feedback mechanisms through calibration circuitry that measures the actual buffer offset and uses this information to adjust and correct the offset error. The calibration process provides feedback about the buffer's actual performance and applies corrective actions, allowing simplified fabrication processes to produce buffers that meet performance specifications despite natural process variations.
Solution Approach 2:
The patent applies parameter changes by adjusting voltage levels and other electrical parameters during calibration to compensate for offset variations. The calibration circuitry modifies operating parameters such as differential voltage levels to correct for fabrication-induced offset variations, enabling consistent buffer performance even when manufacturing precision varies within normal tolerances.
Data Source
AI summary
Methods of operating an integrated circuit device, and integrated circuit devices configured to perform methods, including applying a particular voltage level to a first input of an input/output (I/O) buffer and to a second input of the I/O buffer, determining whether the I/O buffer is deemed to exhibit offset, and applying an adjustment to the I/O buffer offset while applying the particular voltage level to the first input of the I/O buffer and to the second input of the I/O buffer if the I/O buffer is deemed to exhibit offset.