Differential Delta-Sigma Modulator With Single-Ended Amplifiers

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Solution Overview

Problem

Existing hearing aid technologies face challenges in achieving low power consumption while maintaining noise immunity and ease of integration with other circuitries, as differential amplifiers consume more power compared to single-ended amplifiers.

Innovation Solution

A differential delta-sigma modulator using a pair of single-ended amplifiers with a common mode feedback mechanism to maintain noise immunity and reduce power consumption.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Object-affected harmful factors

If differential amplifiers are used in the delta-sigma modulator, then noise immunity is improved, but power consumption increases

Engineering Contradiction:
Improvenoise immunityVSAvoidpower consumption
Core Design Contradiction:
Object-affected harmful factorsVSUse of energy by moving object

Solution Approach 1:

The differential delta-sigma modulator is segmented into two independent single-ended amplifiers that operate in parallel. Each amplifier processes one differential signal independently, allowing the use of simpler single-ended topology while maintaining differential signal processing capabilities. This segmentation resolves the contradiction by enabling noise immunity through differential architecture without the power penalty of traditional differential amplifiers.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The patent merges the advantages of single-ended amplifiers (low power consumption) with the benefits of differential architecture (noise immunity) by combining two single-ended amplifiers to process differential signals. The output of these combined amplifiers provides differential output signals that maintain noise rejection capabilities while consuming less power than conventional differential amplifiers.

Inventive Principle:
Principle #5Merging (Combining)

2Use of energy by moving object

If single-ended amplifiers are used, then power consumption is reduced, but noise immunity deteriorates

Engineering Contradiction:
Improvepower consumptionVSAvoidnoise immunity
Core Design Contradiction:
Use of energy by moving objectVSObject-affected harmful factors

Solution Approach 1:

The patent introduces asymmetry in the signal processing architecture by using single-ended amplifiers that are optimized for low power consumption while still processing differential signals. The asymmetric use of single-ended topology for each side of the differential pair allows power reduction while maintaining the symmetric noise rejection benefits of differential signaling through the combined output.

Inventive Principle:
Principle #4Asymmetry

3Object-affected harmful factors

If differential topology is used for integration, then noise immunity is improved, but device complexity increases

Engineering Contradiction:
Improvenoise immunityVSAvoidcircuit complexity
Core Design Contradiction:
Object-affected harmful factorsVSDevice complexity

Solution Approach 1:

The complex differential topology is segmented into two simpler single-ended amplifier circuits that can be independently designed and implemented. This segmentation reduces device complexity by breaking down the complex differential amplifier into manageable single-ended blocks while maintaining the overall differential functionality for noise immunity.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The patent uses simpler, less complex single-ended amplifier building blocks instead of complex differential amplifiers. These simpler circuits are easier to design, implement, and integrate, reducing overall device complexity while still achieving the desired noise immunity through the differential output configuration.

Inventive Principle:
Principle #27Cheap short-living objects (Disposable)

Data Source

PatentEP4038742B1A differential delta-sigma modulator for a hearing aid
Publication Date: 2025.12.31 WS AUDIOLOGY AS
  • EP4038742B1 patent drawingFigure 1~2
  • EP4038742B1 patent drawingFigure 3~6
  • EP4038742B1 patent drawingFigure 4

AI summary

A differential delta-sigma-modulator has an integrator (49) including a pair of single-ended amplifiers (46, 47). The differential delta-sigma-modulator comprises a sample clock (50) driving a first switchable capacitor configuration (31) and a second switchable capacitor configuration (32) at a predetermined switching cycle. The second switchable capacitor configuration (32) is adapted for sampling respective outputs from the pair of single-ended amplifiers (46, 47) on a pair of output sampling capacitors (C3, C5) in the first part of the switching cycle (P1), and charging a common mode capacitor (C4) with the average voltage of the voltage sampled by the pair of output sampling capacitors (C3, C5) in the second part of the switching cycle (P2). The voltage across the common mode capacitor (C4) represents the common mode voltage for the integrator (49).