Dual-Mode ZQ Calibration Circuit for DRAM Power and Timing Overhead
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Solution Overview
Problem
The frequent ZQ self-calibration process in Dynamic Random Access Memory (DRAM) consumes power and time, leading to resource waste and signal integrity degradation due to impedance mismatch, especially under varying environmental conditions like voltage and temperature.
Innovation Solution
A circuit with an off-chip and on-chip calibration mode allows users to select the ZQ calibration code, reducing the need for frequent self-calibration by allowing external setting when conditions are constant, thereby minimizing power consumption and avoiding noise-induced deviations.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If ZQ self-calibration is performed frequently to adapt to environmental changes, then calibration accuracy is improved, but power consumption increases and system time is occupied
Solution Approach 1:
The patent changes the operational parameters of the calibration system by introducing two distinct calibration modes (self-calibration mode and manual calibration mode) with different calibration frequencies and power consumption characteristics. The system dynamically adjusts between these modes based on environmental conditions, allowing calibration accuracy to be maintained while optimizing power consumption by avoiding unnecessary frequent self-calibration operations when environmental parameters remain stable
2Measurement precision
If ZQ self-calibration is performed frequently to adapt to environmental changes, then calibration accuracy is improved, but system time is occupied and productivity decreases
Solution Approach 1:
The patent introduces a dual-mode calibration system that changes the operational parameters of calibration frequency and method. In self-calibration mode, the system performs automatic calibration when environmental changes are detected, while in manual calibration mode, calibration is performed less frequently based on user input or system state, thereby maintaining calibration accuracy while minimizing impact on memory performance and productivity
3Adaptability or versatility
If on-chip self-calibration is used to adapt to environmental changes, then calibration adaptability is improved, but power consumption and time overhead increase
Solution Approach 1:
The patent implements a dynamic calibration system where the calibration method and frequency are adjusted based on real-time environmental conditions. The system transitions between self-calibration mode (with automatic adaptation to environmental changes) and manual calibration mode (with user-controlled timing), allowing the calibration adaptability to be optimized while minimizing time overhead by performing calibration only when necessary
4Use of energy by moving object
If manual off-chip calibration is used to set ZQ calibration code, then power consumption is reduced, but adaptability to environmental changes decreases
Solution Approach 1:
The patent creates a dynamic calibration system where the user can switch between manual calibration mode (low power consumption) and self-calibration mode (high environmental adaptability) based on operational requirements. The system maintains the ability to adapt to environmental changes through self-calibration mode while allowing power-saving manual calibration mode to be used when environmental conditions are stable, thus resolving the contradiction between power consumption and adaptability
Data Source
AI summary
A calibration control circuit includes an off-chip calibration circuit, an on-chip calibration circuit and a mode switching circuit. The off-chip calibration circuit is configured to receive and store a first calibration code sent by a user. The on-chip calibration circuit is configured to receive an enable signal and perform a ZQ self-calibration process on the memory to obtain a second calibration code adapted to a current environmental parameter when the enable signal is in an active state. The mode switching circuit is configured to receive a calibration mode signal, the first calibration code and the second calibration code, and determine the first calibration code as a ZQ calibration code when the calibration mode signal indicates an off-chip calibration mode, or, determine the second calibration code as the ZQ calibration code when the calibration mode signal indicates an on-chip calibration mode.