Impedance Calibration Circuit Using One Resistor for Multi-Termination

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Solution Overview

Problem

Existing impedance calibration circuits for semiconductor apparatuses are cumbersome and time-consuming due to the need for multiple terminating circuits with different impedance specifications, which complicates the calibration process and increases the size of the circuit.

Innovation Solution

The proposed impedance calibration circuit includes a first and second impedance calibration part, which generate impedance calibration code sets to adjust the impedance of terminating resistors to specific target values, using a single external resistor and a reference resistance unit, thereby simplifying and speeding up the calibration process.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Adaptability or versatility

If multiple terminating circuits with different impedance specifications are used, then different termination requirements are met, but the circuit size and complexity increase

Engineering Contradiction:

Improvetermination impedance specificationVSAvoidcircuit size

Core Design Contradiction:

Adaptability or versatilityVSDevice complexity

Solution Approach 1:

A single external resistor is used to provide reference values for multiple terminating circuits with different impedance specifications. The resistor serves multiple functions: providing reference for first terminating circuit impedance calibration, providing reference for second terminating circuit impedance calibration, and enabling both circuits to achieve their respective termination requirements through shared reference infrastructure.

Inventive Principle:

Principle #6Universality (Multi-functionality)

Solution Approach 2:

The calibration circuits for multiple terminating circuits are merged into a unified structure. The first calibration circuit and second calibration circuit share the external resistor and control logic, combining what would traditionally be separate calibration systems into an integrated solution that reduces overall circuit complexity.

Inventive Principle:

Principle #5Merging (Combining)

2Adaptability or versatility

If multiple terminating circuits with different impedance specifications are used, then different termination requirements are met, but the calibration time increases

Engineering Contradiction:

Improvetermination impedance specificationVSAvoidcalibration time

Core Design Contradiction:

Adaptability or versatilityVSLoss of time

Solution Approach 1:

The external resistor is pre-configured with reference resistance values that can serve multiple calibration purposes. By establishing the reference infrastructure in advance with a single resistor, the system eliminates the need for sequential calibration processes, allowing multiple terminating circuits to be calibrated simultaneously or in rapid succession.

Inventive Principle:

Principle #10Preliminary action

Solution Approach 2:

The shared external resistor enables continuous calibration operations across multiple terminating circuits. Once the reference is established, the calibration process can continuously serve multiple circuits without interruption or reconfiguration, maintaining useful action across the entire system rather than requiring discrete calibration events for each circuit.

Inventive Principle:

Principle #20Continuity of useful action

3Device complexity

If a single external resistor is used for multiple terminating circuits, then circuit size is reduced, but calibration precision may be compromised

Engineering Contradiction:

Improvecircuit sizeVSAvoidimpedance calibration precision

Core Design Contradiction:

Device complexityVSMeasurement precision

Solution Approach 1:

The single external resistor provides different local reference values tailored to each terminating circuit's specific impedance requirements. The first calibration circuit extracts a first reference resistance value suitable for its terminating circuit, while the second calibration circuit extracts a second reference resistance value suitable for its terminating circuit, allowing each to achieve precise calibration for its specific application.

Inventive Principle:

Principle #3Local quality

Solution Approach 2:

The system changes the parameter extraction from the external resistor based on calibration needs. The control logic can selectively use different resistance values or different portions of the external resistor's characteristics for different calibration operations, enabling precise calibration for multiple circuits with different impedance specifications from a single physical component.

Inventive Principle:

Principle #35Parameter changes

Data Source

PatentUS20250166675A1Impedance calibration circuit, memory controller including the impedance calibration circuit and memory system including the memory controller

Publication Date: 2025.05.22 SK HYNIX INC

AI summary

A first impedance calibration part configured to perform a first impedance calibration operation of generating a first impedance calibration code set for adjusting an impedance of a first terminating resistor to a first target value, with reference to an external resistor having a first resistance value. A second impedance calibration part configured to perform a second impedance calibration operation of generating a second impedance calibration code set for adjusting an impedance of a second terminating resistor to a second target value, with reference to a reference resistance unit, a resistance value of which is set to a second resistance value according to a part of the first impedance calibration code set.