Shared Calibration Impedance Circuit for Differential and Common-Mode Matching

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Solution Overview

Problem

Existing input/output (I/O) interfaces require separate calibration circuits for differential-mode and common-mode impedance matching, leading to increased power consumption and calibration time.

Innovation Solution

An adjustable impedance circuit with a calibration module, impedance module, and switch modules that can selectively couple impedance elements between input ports and reference or common-mode voltage nodes, allowing for simultaneous differential-mode and common-mode impedance matching using a single calibration circuit.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If separate calibration circuits are used for differential-mode and common-mode impedance matching, then both impedance matching requirements are met, but power consumption and calibration time increase

Engineering Contradiction:

Improveimpedance matching performanceVSAvoidpower consumption

Core Design Contradiction:

ReliabilityVSUse of energy by moving object

Solution Approach 1:

The patent combines differential-mode and common-mode impedance calibration functions into a single shared calibration circuit. The calibration circuit can be selectively connected to different impedance elements through switching mechanisms, allowing one calibration circuit to perform both calibration functions sequentially, thereby reducing power consumption while maintaining matching performance.

Inventive Principle:

Principle #5Merging (Combining)

Solution Approach 2:

The calibration circuit is designed with multi-functionality to handle both differential-mode and common-mode impedance calibration. By incorporating switching elements that can connect the calibration circuit to different portions of impedance elements, a single calibration circuit achieves universal calibration capability for both modes, eliminating the need for separate dedicated circuits.

Inventive Principle:

Principle #6Universality (Multi-functionality)

2Reliability

If separate calibration circuits are used for differential-mode and common-mode impedance matching, then both impedance matching requirements are met, but circuit area increases

Engineering Contradiction:

Improveimpedance matching performanceVSAvoidcircuit area

Core Design Contradiction:

ReliabilityVSArea of stationary object

Solution Approach 1:

The patent merges the functionality of separate calibration circuits into a single shared calibration circuit. This calibration circuit can be selectively connected to different impedance elements through switching mechanisms, reducing the total circuit area while maintaining the capability to perform both differential-mode and common-mode impedance calibration.

Inventive Principle:

Principle #5Merging (Combining)

Solution Approach 2:

The patent introduces dynamic switching mechanisms that allow a single calibration circuit to be reconfigured for different calibration functions. The switching elements enable the calibration circuit to dynamically connect to different portions of impedance elements, providing flexible multi-functionality without requiring separate static calibration circuits for each mode.

Inventive Principle:

Principle #15Dynamics

3Reliability

If separate calibration circuits are used for differential-mode and common-mode impedance matching, then both impedance matching requirements are met, but calibration time increases

Engineering Contradiction:

Improveimpedance matching performanceVSAvoidcalibration time

Core Design Contradiction:

ReliabilityVSLoss of time

Solution Approach 1:

The patent combines differential-mode and common-mode calibration functions into a single calibration circuit that can operate sequentially. The switching mechanisms allow the calibration circuit to be rapidly reconfigured between different calibration functions, reducing total calibration time while maintaining comprehensive impedance matching performance for both modes.

Inventive Principle:

Principle #5Merging (Combining)

Solution Approach 2:

The patent employs dynamic switching elements that enable rapid reconfiguration of the calibration circuit between differential-mode and common-mode calibration functions. This dynamic capability allows the single calibration circuit to perform both calibration tasks efficiently in sequence, minimizing total calibration time compared to separate dedicated circuits operating in parallel.

Inventive Principle:

Principle #15Dynamics

Data Source

PatentUS8896343B2Adjustable impedance circuit and impedance setting method for providing differential-mode impedance matching and common-mode impedance matching

Publication Date: 2014.11.25 REALTEK SEMICON CORP

AI summary

An adjustable impedance circuit includes a calibration module, an impedance module, a first switch module and a second switch module. The calibration module is arranged to generate a calibration signal. The impedance module has a plurality of impedance elements. The first switch module is coupled to the calibration module, and is arranged to receive the calibration signal and make a first portion of the impedance elements be selectively coupled between a differential input port and at least one reference voltage according to the calibration signal. The second switch module is coupled to a common-mode voltage output node, and is arranged to receive a control signal and make a second portion of the impedance elements be selectively coupled between the common-mode voltage output node and the differential input port according to the control signal.