Memory Input Buffer Offset Calibration via Gain-Adaptive Current Adjustment
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Solution Overview
Problem
Volatile memory devices, such as DRAM, face errors during analog-to-digital conversion due to potential input offsets in the input buffer, necessitating an input offset calibration operation.
Innovation Solution
The memory device obtains an offset calibration code for the input buffer circuit before receiving a mode register code and adjusts the current amount supplied to a current element connected to the input terminal of the input buffer circuit after receiving the mode register code, effectively calibrating the input offset.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If input offset calibration is performed using traditional methods after receiving mode register code, then the calibration can be performed with correct gain information, but the calibration time and device operation delay increase
Solution Approach 1:
The patent performs offset calibration code generation before receiving the mode register code. The input/output circuit generates an offset calibration code corresponding to a first input offset of the input buffer based on second data, before receiving the mode register code including gain information. This preliminary action allows the calibration data to be prepared in advance, reducing calibration time when actually needed.
Solution Approach 2:
The patent changes the gain of the input buffer based on the mode register code after receiving it, and then calibrates a second input offset corresponding to the changed gain by adjusting a current amount applied to a current element connected to an input terminal of the input buffer. This parameter change approach allows the system to adapt the calibration to different gain settings without performing full calibration each time.
2Productivity
If input offset calibration is performed without considering gain changes, then the calibration process is simpler and faster, but the calibration accuracy deteriorates due to gain variations
Solution Approach 1:
The patent dynamically adjusts the gain of the input buffer based on the mode register code and performs offset calibration corresponding to the changed gain by adjusting the current amount. This dynamic adaptation ensures that the calibration remains accurate even as operating conditions change, rather than using a fixed calibration approach.
Solution Approach 2:
The patent generates an offset calibration code based on second data from the input buffer, and then uses this calibration code to adjust the input offset. The system creates a calibration profile that can be applied and adjusted for different gain settings, effectively copying and adapting the calibration data rather than performing complete recalibration each time.
3Measurement precision
If the current amount supplied to the input buffer is adjusted frequently to maintain calibration accuracy, then the calibration precision is maintained, but the energy consumption increases
Solution Approach 1:
The patent generates the offset calibration code in advance before receiving the mode register code. This preliminary generation of calibration data reduces the need for frequent current adjustments, as the calibration information is prepared beforehand and can be applied efficiently when gain changes occur.
Solution Approach 2:
The patent adjusts the current amount applied to the current element based on the offset calibration code and mode register code only when gain changes are detected. This selective parameter adjustment maintains calibration accuracy while avoiding unnecessary energy consumption from continuous or frequent adjustments.
Data Source
AI summary
A memory device includes a memory cell array and an input/output circuit. The input/output circuit is configured to: (i) generate second data in response to sampling first data by comparing the first data against a reference voltage, (ii) generate an offset calibration code corresponding to a first input offset of the input/output circuit based on the second data, prior to receiving a mode register code, (iii) change a gain of an input buffer corresponding to the mode register code after receiving the mode register code, and (iv) calibrate a second input offset corresponding to the changed gain of the input buffer by adjusting a current amount applied to a current element electrically connected to an input terminal of the input buffer based on the offset calibration code and the mode register code. Control logic may also be used to provide the mode register code, which includes gain information associated with the input/output circuit, to the input/output circuit.