ZQ Calibration Control Circuit for Low-Power DRAM Timing

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Solution Overview

Problem

The ZQ calibration process in DRAM consumes significant power and system time, reducing memory performance and introducing signal integrity issues due to environmental noise.

Innovation Solution

A circuit for controlling calibration that allows users to select between on-chip and off-chip calibration modes to determine the ZQ calibration code, reducing the need for frequent self-calibration and minimizing power consumption and system time.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Measurement precision

If ZQ calibration is performed frequently to ensure signal integrity, then measurement precision is improved, but power consumption increases and system time is occupied

Engineering Contradiction:
Improvesignal integrityVSAvoidpower consumption
Core Design Contradiction:
Measurement precisionVSUse of energy by moving object

Solution Approach 1:

The patent pre-stores calibration codes corresponding to different voltage/temperature conditions in a register array before actual operation. When the current condition matches a pre-stored condition, the pre-calibrated code is directly retrieved without performing new calibration, thus avoiding repeated power consumption while maintaining signal integrity.

Inventive Principle:
Principle #10Preliminary action

Solution Approach 2:

The patent creates copies of calibration codes for different environmental conditions and stores them in advance. Instead of recalibrating each time, the system copies and uses the appropriate pre-stored calibration code that matches the current voltage/temperature condition, significantly reducing power consumption while maintaining calibration accuracy.

Inventive Principle:
Principle #26Copying

2Manufacturing precision

If ZQ calibration is performed frequently to match working conditions, then manufacturing precision is improved, but productivity deteriorates

Engineering Contradiction:
Improveresistance value calibrationVSAvoidmemory performance
Core Design Contradiction:
Manufacturing precisionVSProductivity

Solution Approach 1:

The system performs calibration code preparation in advance and stores multiple calibration codes corresponding to different voltage/temperature conditions in a register array. During operation, the system directly retrieves the matching pre-prepared calibration code based on current conditions, avoiding time-consuming recalibration processes and thus improving memory performance while maintaining calibration precision.

Inventive Principle:
Principle #10Preliminary action

Solution Approach 2:

Multiple calibration codes are copied and stored in the register array for different environmental conditions. The system copies the appropriate calibration code based on current voltage/temperature conditions and applies it directly, eliminating the need for repeated calibration operations and thereby improving productivity while maintaining manufacturing precision.

Inventive Principle:
Principle #26Copying

3Adaptability or versatility

If on-chip calibration is performed to adapt to environmental changes, then adaptability is improved, but device complexity increases

Engineering Contradiction:
Improvevoltage/temperature adaptationVSAvoidcalibration control circuit
Core Design Contradiction:
Adaptability or versatilityVSDevice complexity

Solution Approach 1:

The calibration control circuit is designed to handle multiple voltage/temperature conditions using a unified structure. The register array stores calibration codes for various conditions, and the control logic universally manages code selection and application across different environmental scenarios, achieving high adaptability without proportionally increasing circuit complexity.

Inventive Principle:
Principle #6Universality (Multi-functionality)

Solution Approach 2:

The system adapts to environmental changes by changing the selected calibration code parameter based on detected voltage/temperature conditions. Instead of redesigning the circuit for each condition, the system maintains a fixed circuit structure that selects different calibration codes (parameter changes) from the register array, achieving adaptability with minimal complexity increase.

Inventive Principle:
Principle #35Parameter changes

Data Source

PatentEP4290518B1Calibration control circuit, electronic device and calibration control method
Publication Date: 2025.01.29 CHANGXIN MEMORY TECH INC
  • EP4290518B1 patent drawingFigure 1
  • EP4290518B1 patent drawingFigure 2
  • EP4290518B1 patent drawingFigure 3

AI summary

Embodiments of the present disclosure provide a circuit for controlling calibration, an electronic device, and a method for controlling calibration. The calibration control circuit includes an off-chip calibration module, an on-chip calibration module and a mode switching module. The off-chip calibration module is configured to receive and store a first calibration code sent by a user. The on-chip calibration module 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 in a case that the enable signal is in an active state. The mode switching module 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 in the case that the calibration mode signal indicates an off-chip calibration mode, or, determine the second calibration code as the ZQ calibration code in a case that the calibration mode signal indicates an on-chip calibration mode.