Data Input Buffer Offset Correction Using Impedance Calibration Codes
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Solution Overview
Problem
Semiconductor apparatus data input buffers experience operational reliability degradation due to signal offsets caused by variations in power, voltage, and temperature, affecting overall performance.
Innovation Solution
Incorporating a data input buffer with multiple buffer units that receive impedance calibration codes to detect and correct offsets, utilizing an impedance calibration circuit to perform offset correction and impedance calibration operations based on mode register settings and commands.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a data input buffer operates without offset correction, then the device complexity is low, but the operational reliability degrades due to PVT variations causing signal offsets
Solution Approach 1:
The patent applies preliminary action by performing offset correction before normal data input operations. The buffer unit detects and corrects offsets using calibration codes during an initialization phase, ensuring that the buffer is properly calibrated before actual data processing begins. This preliminary calibration eliminates the need for continuous complex correction mechanisms during operation.
Solution Approach 2:
The buffer unit performs self-service by autonomously detecting its own offset errors and correcting them using internally generated calibration codes. The short-circuiting mechanism allows the buffer to self-test and self-correct without external intervention, maintaining reliability while keeping the overall system complexity manageable.
2Reliability
If offset correction is performed continuously, then the operational reliability is maintained, but the productivity decreases due to additional calibration operations
Solution Approach 1:
The patent implements periodic action by performing offset correction only at specific intervals rather than continuously. The buffer unit corrects offsets based on periodic calibration commands or at predetermined time intervals, maintaining reliability while minimizing interference with normal data processing operations and preserving productivity.
3Measurement precision
If multiple buffer units are used for offset detection and correction, then the measurement precision of offset improves, but the device complexity increases
Solution Approach 1:
The patent applies segmentation by dividing the buffer into multiple independent buffer units, each capable of detecting and correcting offsets autonomously. This segmentation allows parallel offset detection across different units, improving overall measurement precision while keeping each individual unit relatively simple in structure.
Solution Approach 2:
Each buffer unit is designed with multi-functionality, serving both as a data buffer and as an offset detection/correction unit. The same buffer unit structures are used for both normal data operation and calibration operations, eliminating the need for separate dedicated offset detection circuits and thereby reducing overall device complexity.
Data Source
AI summary
A data input buffer includes a plurality of buffer units configured to receive a first impedance calibration code and a second impedance calibration code, wherein each of the plurality of buffer units outputs an offset detected with a first input terminal and a second input terminal thereof short-circuited, as write data, and wherein a buffer unit corresponding to a current value of the first impedance calibration code among the plurality of buffer units is configured to correct the offset according to the second impedance calibration code.