Memory Interface Output Impedance Monitoring for Continuous Calibration

Solution Overview

Problem

Conventional output impedance calibration in memory interface circuits interrupts data transmission, leading to reduced data transmission efficiency due to the need for stopping data transmission during calibration processes.

Innovation Solution

A memory interface circuit with an output impedance monitor and calibrator that allows for real-time impedance calibration without interrupting data transmission, using a control circuit to output digital signals, a driving circuit to generate output signals, and an output impedance calibrator to adjust impedance based on monitoring signals from the output impedance monitor.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Measurement precision

If output impedance calibration is performed during memory interface operation, then impedance calibration accuracy is improved, but data transmission efficiency deteriorates due to transmission interruption

Engineering Contradiction:

Improveimpedance calibration accuracyVSAvoiddata transmission efficiency

Core Design Contradiction:

Measurement precisionVSProductivity

Solution Approach 1:

The patent performs impedance calibration in advance during initialization or idle periods before data transmission begins, or prepares calibration results beforehand. This allows the system to have impedance calibration data ready before transmission starts, avoiding interruption during actual data transfer operations.

Inventive Principle:

Principle #10Preliminary action

Solution Approach 2:

The patent implements periodic impedance calibration at predetermined time intervals or at specific phases during memory interface operation. Instead of continuous calibration that would constantly interrupt transmission, the system performs calibration periodically when transmission is naturally paused or at scheduled moments, balancing calibration accuracy with transmission efficiency.

Inventive Principle:

Principle #19Periodic action

2Measurement precision

If output impedance calibration is performed during memory interface operation, then impedance calibration accuracy is improved, but time consumption increases

Engineering Contradiction:

Improveimpedance calibration accuracyVSAvoidcalibration time

Core Design Contradiction:

Measurement precisionVSLoss of time

Solution Approach 1:

The patent performs impedance calibration in advance during initialization or idle periods before data transmission begins, or prepares calibration results beforehand. This allows the system to have impedance calibration data ready before transmission starts, avoiding interruption during actual data transfer operations.

Inventive Principle:

Principle #10Preliminary action

Solution Approach 2:

The patent employs self-calibration mechanisms where the memory interface circuit automatically performs impedance calibration without requiring external intervention or stopping normal operations. The system uses its own internal resources and signals to conduct calibration, reducing the time and overhead associated with external calibration processes.

Inventive Principle:

Principle #25Self-service

3Measurement precision

If data transmission is stopped during output impedance calibration, then impedance calibration accuracy is improved, but actual data transmission efficiency per unit time decreases

Engineering Contradiction:

Improveimpedance calibration accuracyVSAvoidactual data transmission efficiency per unit time

Core Design Contradiction:

Measurement precisionVSProductivity

Solution Approach 1:

The patent performs impedance calibration in advance during initialization or idle periods before data transmission begins, or prepares calibration results beforehand. This allows the system to have impedance calibration data ready before transmission starts, avoiding interruption during actual data transfer operations.

Inventive Principle:

Principle #10Preliminary action

Solution Approach 2:

The patent enables continuous data transmission by performing impedance calibration in parallel with transmission operations or by rapidly interleaving calibration and transmission. The system maintains continuous useful action by ensuring that calibration does not create gaps in data transmission, thereby preserving transmission efficiency while still achieving calibration accuracy.

Inventive Principle:

Principle #20Continuity of useful action

Data Source

PatentUS11190188B2Memory interface circuit including output impedance monitor and method of calibrating output impedance thereof

Publication Date: 2021.11.30 ELECTRONICS & TELECOMM RES INST

AI summary

Disclosed are a memory interface circuit including an output impedance monitor, which is capable of monitoring and calibrating an output impedance of a driving circuit in real time, and a method of calibrating the output impedance. The memory interface circuit includes a control circuit that outputs a digital transmission signal, a driving circuit that outputs an output signal, based on the digital transmission signal, an output impedance monitor that outputs a pull-up monitoring signal or a pull-down monitoring signal, based on the digital transmission signal and the output signal, and an output impedance calibrator that outputs an impedance monitoring signal, based on the pull-up monitoring signal or the pull-down monitoring signal, and wherein the driving circuit calibrates output impedance based on the impedance monitoring signal.