Pre-Tap CTLE Circuit for Inter-Symbol Interference Reduction

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Solution Overview

Problem

Existing serial communication systems face high frequency distortion and inter-symbol interference due to lossy channels, which are not effectively addressed by current channel equalization methods, particularly in systems with increased data rates and modulation complexity.

Innovation Solution

Implementing a continuous time linear equalizer circuit with pre-tap equalization capability, utilizing transistors and capacitors to enhance signal recovery by enabling switchable pre-tap equalization, reducing power consumption and circuit area compared to discrete time feed-forward equalizers.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If discrete time feed-forward equalizers are used to address high frequency distortion and inter-symbol interference, then equalization performance is improved, but power consumption and circuit area increase

Engineering Contradiction:

Improveequalization performanceVSAvoidpower consumption

Core Design Contradiction:

ReliabilityVSUse of energy by moving object

Solution Approach 1:

The patent replaces discrete-time digital signal processing with continuous-time analog equalization using transistor-based circuits. This substitution enables pre-tap equalization functionality while significantly reducing power consumption and circuit area compared to traditional discrete-time feed-forward equalizers, directly addressing the technical contradiction between equalization performance and power consumption.

Inventive Principle:

Principle #28Mechanics substitution (Replace mechanical system)

Solution Approach 2:

The patent implements switchable pre-tap equalization capability by changing the operational parameters of the equalizer circuit. Through control signals, the circuit can dynamically adjust between different equalization modes (pre-tap, post-tap, or none), allowing optimization of power consumption based on actual channel conditions while maintaining effective equalization performance.

Inventive Principle:

Principle #35Parameter changes

2Reliability

If discrete time feed-forward equalizers are used to address high frequency distortion and inter-symbol interference, then equalization performance is improved, but circuit area increases

Engineering Contradiction:

Improveequalization performanceVSAvoidcircuit area

Core Design Contradiction:

ReliabilityVSArea of stationary object

Solution Approach 1:

Inventive Principle:

Principle #28Mechanics substitution (Replace mechanical system)

Solution Approach 2:

The patent combines multiple equalization functions (pre-tap and post-tap equalization) into a single integrated continuous-time circuit structure. By merging these functions and using shared transistor components, the circuit achieves comprehensive equalization performance while minimizing the overall circuit area compared to separate discrete-time equalizer blocks.

Inventive Principle:

Principle #5Merging (Combining)

3Measurement precision

If channel equalization is applied to counteract inter-symbol interference, then signal quality is improved, but complexity of the equalization system increases

Engineering Contradiction:

Improvesignal qualityVSAvoidequalization system complexity

Core Design Contradiction:

Measurement precisionVSDevice complexity

Solution Approach 1:

The patent replaces complex discrete-time digital signal processing algorithms with simpler continuous-time analog circuit implementations. The transistor-based continuous-time equalizer achieves effective inter-symbol interference cancellation through analog signal manipulation, reducing the computational and structural complexity typically associated with high-performance equalization systems.

Inventive Principle:

Principle #28Mechanics substitution (Replace mechanical system)

Data Source

PatentUS20250365180A1Pre-tap equalizable continuous time linear equalizer

Publication Date: 2025.11.27 TEXAS INSTRUMENTS INC

AI summary

A circuit includes first, second, third, and fourth transistors, and a capacitor. The first transistor has a first terminal, a second terminal, and a control terminal. The second transistor has a first terminal, second terminal, and a control terminal. The capacitor has a first conductor coupled to the second terminal of the first transistor, and a second conductor coupled to the second terminal of the second transistor. The third transistor has a first terminal coupled to the first terminal of the second transistor, a second terminal, and a control terminal coupled to the control terminal of the first transistor. The fourth transistor has a first terminal coupled to the first terminal of the first transistor, a second terminal coupled to the second terminal of the third transistor, and a control terminal coupled to the control terminal of the second transistor.