Data Input Buffer Offset Calibration Using Sequential Codes
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Solution Overview
Problem
Conventional data input buffers in semiconductor memory devices suffer from inefficient offset calibration processes, leading to increased time requirements due to repeated adjustments of calibration codes based on voltage transitions, which are not aligned with reference voltages.
Innovation Solution
A data input buffer design that includes a switching circuit to equalize reception and reference voltages, a reception circuit with response units to generate buffered data signals based on conductance relationships, and a code generating circuit to sequentially change calibration codes, allowing for efficient calibration of offset in a calibration mode without affecting normal operation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If conventional offset calibration method is used with repeated voltage transitions and calibration code adjustments, then offset calibration is achieved, but calibration time is excessively increased
Solution Approach 1:
The switching circuit equalizes the reception input signal voltage and reference voltage to substantially the same level before calibration begins. This preliminary voltage equalization eliminates the need for repeated voltage transitions during calibration, as the calibration process can directly adjust calibration codes while maintaining stable voltage conditions, thereby significantly reducing calibration time while preserving calibration accuracy
Solution Approach 2:
The invention changes the calibration approach from repeatedly transitioning voltage levels to sequentially activating calibration codes (first calibration code, second calibration code, etc.) while maintaining equalized voltages. The code generating circuit generates calibration codes in sequence, and the switching circuit maintains voltage equalization throughout this process, allowing offset calibration to be achieved through parameter changes in the calibration codes rather than through repeated voltage transitions
Data Source
AI summary
A data input buffer includes a switching circuit; a reception circuit that includes a reception response unit and a reference response unit; and a code generating circuit. The data input buffer buffers a reception data signal to generate a buffered data signal, the reception data signal being an analog signal, and the buffered data signal being a digital signal, and a relative magnitude of a reference response conductance with respect to the reception response conductance is sequentially changed according to a sequential change of the calibration code, in the calibration mode.