Differential Amplifier Resistor Switching for LPDDR4 Strobe Noise

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Solution Overview

Problem

LPDDR4 memory devices experience malfunctions due to noise amplification of data strobe signals by differential amplifiers, leading to control circuit failures when the write data strobe function is off.

Innovation Solution

A memory device with a receiver circuit that includes a differential amplifier, on-die terminators, and noise-suppression circuits controlled by a noise-suppression control circuit to selectively couple resistors based on mode register settings and data strobe signal conditions for adaptive noise suppression.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Use of energy by moving object

If the write data strobe function is turned off, then power consumption is reduced, but noise on data strobe signals is amplified leading to control circuit failures

Engineering Contradiction:

Improvepower consumptionVSAvoidcontrol circuit functionality

Core Design Contradiction:

Use of energy by moving objectVSReliability

Solution Approach 1:

The patent introduces an intermediary noise suppression circuit between the differential amplifier and the control circuit. This circuit includes additional amplifiers and resistors that actively suppress noise on data strobe signals when the write data strobe function is disabled, preventing noise amplification from causing control circuit failures while maintaining low power consumption mode

Inventive Principle:

Principle #24Intermediary (Mediator)

Solution Approach 2:

The patent implements dynamic noise suppression by selectively enabling or disabling noise suppression circuits based on the write data strobe function state. When WDQS is disabled, the noise suppression circuit is activated to suppress noise; when WDQS is enabled, the noise suppression circuit is deactivated. This dynamic adaptation resolves the contradiction between power savings and reliability

Inventive Principle:

Principle #15Dynamics

2Power

If the differential amplifier amplifies data strobe signals, then signal strength is improved, but noise is also amplified leading to logic state errors

Engineering Contradiction:

Improvesignal strengthVSAvoidnoise amplification

Core Design Contradiction:

PowerVSObject-affected harmful factors

Solution Approach 1:

The patent converts the harmful noise amplification effect into a beneficial noise suppression mechanism. The noise suppression circuit uses additional differential amplifiers to detect and suppress noise components on the data strobe signals. By processing the amplified signals through these additional stages with appropriate resistor networks, the circuit selectively attenuates noise while preserving the valid signal components, thus converting the harmful noise amplification into a benefit where the amplification is followed by intelligent noise rejection

Inventive Principle:

Principle #22Blessing in disguise (Convert harm into benefit)

3Reliability

If noise suppression circuits are added to suppress noise on data strobe signals, then reliability is improved, but device complexity increases

Engineering Contradiction:

Improvedata strobe signal integrityVSAvoidreceiver circuit structure

Core Design Contradiction:

ReliabilityVSDevice complexity

Solution Approach 1:

The patent segments the receiver circuit into distinct functional blocks: the main differential amplifier stage, the noise suppression control circuit, and the noise suppression execution circuits. Each segment has a specific function - the main amplifier boosts signal strength, the control circuit determines when noise suppression is needed, and the execution circuits apply noise suppression. This segmentation allows the complex noise suppression functionality to be added in a modular way, managing complexity through functional decomposition

Inventive Principle:

Principle #1Segmentation

Applied Scientific Principles

This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.

Function Achieved in This Case

Effectively suppresses noise on data strobe signals, maintaining accurate logic states and preventing control circuit failures, ensuring compliance with LPDDR4 standards.

Implementation Method 1

The differential amplifier is configured to amplify the first data strobe signal and the second data strobe signal to generate a third data strobe signal and a fourth data strobe signal

Methodology Applied

Scientific EffectDifferential amplification:

Implementation Method 2

The first noise-suppression circuit is configured to selectively couple a first resistor to the first input terminal of the differential amplifier according to the third data strobe signal, the fourth data strobe signal, and the noise-suppression control signal

Methodology Applied

Scientific EffectElectrical resistance: Electrical Resistance

Data Source

PatentUS12469524B2Method for adaptive noise suppression on data strobe signals and memory device using the same

Publication Date: 2025.11.11 NAN YA TECH

AI summary

A method for adaptive noise suppression on data strobe signals is provided. The method includes the following steps: determining whether a first data strobe signal and a second data strobe signal satisfy a first condition; in response to the first data strobe signal and the second data strobe signal satisfying the first condition, determining whether a mode register setting value (MRSV) associated with a first on-die terminator and a second on-die terminator is greater than N; and in response to the MRSV being not greater than N, decoupling a first resistor and a second resistor from a first input terminal and a second input terminal of a differential amplifier, respectively; and in response to the MRSV being greater than N, coupling the first resistor and the second resistor to the first input terminal and the second input terminal of the differential amplifier, respectively.