Analog Beamforming Circuit for Low-Power Sound Source Separation

Solution Overview

Problem

Beamformers used for sound source separation require a large number of microphones, leading to increased power consumption and processing demands, particularly in portable devices that need to operate for extended periods with limited battery life, as they necessitate analog-to-digital conversion and complex signal processing.

Innovation Solution

A semiconductor device incorporating a microphone array with delay circuits and signal retention circuits that utilize metal oxide transistors to sample and retain analog sound signals, allowing for sound source separation without digital conversion, thereby reducing power consumption and processing requirements.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If a beamformer with multiple microphones is used for sound source separation, then sound separation capability is improved, but power consumption increases

Engineering Contradiction:

Improvesound separation capabilityVSAvoidpower consumption

Core Design Contradiction:

ReliabilityVSUse of energy by moving object

Solution Approach 1:

The patent extracts only the essential delay and addition functions needed for beamforming, implementing them directly in the analog domain using simple circuit elements (resistors, capacitors, operational amplifiers) rather than full digital signal processing chains. This extraction of core functionality eliminates power-hungry A/D conversion and complex digital processing while maintaining sound separation capability.

Inventive Principle:

Principle #2Taking out (Extraction)

Solution Approach 2:

The patent replaces the mechanical/electronic system of A/D conversion and digital processing with an analog electrical system that performs delay and addition operations directly on voltage signals. This substitution eliminates the need for digital converters and processors, significantly reducing power consumption while achieving the same beamforming effect.

Inventive Principle:

Principle #28Mechanics substitution (Replace mechanical system)

2Reliability

If a beamformer with multiple microphones is used for sound source separation, then sound separation capability is improved, but processing complexity increases

Engineering Contradiction:

Improvesound separation capabilityVSAvoidprocessing complexity

Core Design Contradiction:

ReliabilityVSDevice complexity

Solution Approach 1:

The patent extracts only the essential delay and addition functions needed for beamforming, implementing them directly in the analog domain using simple circuit elements (resistors, capacitors, operational amplifiers) rather than full digital signal processing chains. This extraction of core functionality eliminates power-hungry A/D conversion and complex digital processing while maintaining sound separation capability.

Inventive Principle:

Principle #2Taking out (Extraction)

Solution Approach 2:

The patent replaces the mechanical/electronic system of A/D conversion and digital processing with an analog electrical system that performs delay and addition operations directly on voltage signals. This substitution eliminates the need for digital converters and processors, significantly reducing power consumption while achieving the same beamforming effect.

Inventive Principle:

Principle #28Mechanics substitution (Replace mechanical system)

3Use of energy by moving object

If analog signals are processed without A/D conversion, then power consumption is reduced, but signal processing capability is limited

Engineering Contradiction:

Improvepower consumptionVSAvoidsignal processing capability

Core Design Contradiction:

Use of energy by moving objectVSAdaptability or versatility

Solution Approach 1:

The patent creates a universal analog beamforming circuit that can process signals from any number of microphones arranged in various geometries. The same operational amplifier-based addition circuit can handle different microphone configurations and sound source positions, providing adaptability without requiring digital processing or A/D conversion.

Inventive Principle:

Principle #6Universality (Multi-functionality)

Solution Approach 2:

The patent achieves adaptability by changing circuit parameters (resistor values, capacitor values, op-amp gain settings) rather than requiring complex digital processing. By adjusting these analog parameters, the same hardware circuit can be tuned to different microphone configurations and optimization criteria, maintaining versatility while staying in the analog domain.

Inventive Principle:

Principle #35Parameter changes

Data Source

PatentUS11689850B2Sound source separation device, semiconductor device, and electronic device

Publication Date: 2023.06.27 SEMICON ENERGY LAB CO LTD

AI summary

Provided is a semiconductor device that does not require an A/D converter circuit and is capable of performing sound source separation without converting an analog signal. The semiconductor device includes a plurality of microphones, a plurality of delay circuits, and a signal processing circuit. The plurality of microphones are electrically connected to the respective delay circuits, and output signals of the plurality of delay circuits are input to the signal processing circuit. The delay circuit includes a plurality of signal retention circuits capable of retaining an analog potential, and has functions of retaining an electric signal output from the microphone as a discrete analog signal in the signal retention circuits and outputting the signal at a time different from the time when the microphone outputs the signal. The signal processing circuit has a function of adding the output signals of the plurality of delay circuits.