Semiconductor Impedance Calibration Using Shared Resistor Arbitration

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Solution Overview

Problem

As the number of semiconductor devices coupled to a shared external resistance for calibration increases, it becomes challenging to complete calibration operations for all devices within a specified time period, leading to potential impedance mismatches and data distortion, especially as operational speeds increase and signal swing widths decrease.

Innovation Solution

A calibration circuit that arbitrates among multiple semiconductor devices for use of the shared external resistance, allowing for background calibration operations and automatic application of calibration parameters without relying on memory controller commands, thereby reducing the total time required for calibration and preventing contention.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Area of stationary object

If multiple semiconductor devices share a common external resistance for calibration, then the number of external connections is reduced, but calibration contention arises and total calibration time increases

Engineering Contradiction:

Improvenumber of external connectionsVSAvoidtotal calibration time

Core Design Contradiction:

Area of stationary objectVSLoss of time

Solution Approach 1:

The calibration circuit performs calibration operations in the background before memory commands are executed. By completing calibration preliminarily and storing results in calibration storage circuits, the system avoids contention for the shared external resistance during normal operation and eliminates the need to wait for calibration to complete before processing memory commands.

Inventive Principle:

Principle #10Preliminary action

Solution Approach 2:

The calibration process is divided into separate calibration circuits for different impedance components (e.g., first calibration circuit for pull-down impedance, second calibration circuit for pull-up impedance). Each calibration circuit independently calibrates its specific component using the shared external resistance, allowing parallel calibration operations that reduce total calibration time and eliminate contention.

Inventive Principle:

Principle #1Segmentation

2Reliability

If calibration operations are performed sequentially for multiple devices, then contention for the shared external resistance is avoided, but the total calibration time becomes impractically long

Engineering Contradiction:

Improvecalibration accuracyVSAvoidcalibration throughput

Core Design Contradiction:

ReliabilityVSProductivity

Solution Approach 1:

The system divides calibration into separate independent circuits for different impedance components. Each calibration circuit can operate independently and simultaneously use the shared external resistance without interfering with other calibration circuits, enabling parallel calibration that maintains accuracy while dramatically increasing throughput.

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

Calibration operations are performed continuously in the background without interruption to normal memory operations. The calibration circuit continuously monitors and adjusts impedance parameters, ensuring calibration accuracy is maintained while the system remains fully operational, thus achieving both reliability and high productivity.

Inventive Principle:

Principle #20Continuity of useful action

3Stability of the object's composition

If calibration parameters are applied after a specified time period following calibration initiation, then calibration stability is ensured, but devices with more components cannot complete calibration before the time period expires

Engineering Contradiction:

Improvecalibration stabilityVSAvoidnumber of devices supported

Core Design Contradiction:

Stability of the object's compositionVSAdaptability or versatility

Solution Approach 1:

The calibration circuit completes calibration operations preliminarily and stores results in calibration storage circuits before the specified time period expires. By preparing calibration parameters in advance and storing them for later application, the system can support multiple devices with complex calibration requirements while maintaining the required stability through controlled parameter application timing.

Inventive Principle:

Principle #10Preliminary action

Data Source

PatentUS11916527B2Apparatuses and methods for calibrating adjustable impedances of a semiconductor device

Publication Date: 2024.02.27 LODESTAR LICENSING GROUP LLC

AI summary

Apparatuses and methods for calibrating adjustable impedances of a semiconductor device are disclosed in the present application. An example apparatus includes a register configured to store impedance calibration information and further includes programmable termination resistances having a programmable impedance. The example apparatus further includes an impedance calibration circuit configured to perform a calibration operation to determine calibration parameters for setting the programmable impedance of the programmable termination resistances. The impedance calibration circuit is further configured to program the impedance calibration information in the register related to the calibration operation.