Audio Amplifier IC Gain Signaling Without Extra Terminals

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Solution Overview

Problem

Existing integrated circuits face challenges in achieving high dynamic range signal processing without additional terminals, particularly in miniaturized designs, where providing extra terminals for gain information is problematic, and existing circuit arrangements may not support additional connections.

Innovation Solution

An integrated circuit with a signal strength detector and signaling circuit that adjusts amplification settings based on detected signal strength, using existing terminals to indicate amplification settings through changes in supply voltage or output signal, eliminating the need for additional terminals by signaling via impedance changes, offset voltages, or control signals.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Adaptability or versatility

If an additional terminal is provided to output gain information, then signal processing capability is improved, but device complexity and terminal quantity increase

Engineering Contradiction:
Improvesignal processing capabilityVSAvoidterminal quantity
Core Design Contradiction:
Adaptability or versatilityVSDevice complexity

Solution Approach 1:

The existing output terminal is made multi-functional by enabling it to convey both the amplified audio signal and gain information simultaneously. The signaling circuit superimposes gain information onto the output signal, allowing the same terminal to serve dual purposes: audio output and gain status indication, thereby eliminating the need for an additional dedicated terminal

Inventive Principle:
Principle #6Universality (Multi-functionality)

Solution Approach 2:

The gain information output function is merged with the audio signal output function. The signaling circuit combines the gain information with the amplified output signal, so that a single terminal carries both types of information, reducing the total number of terminals required

Inventive Principle:
Principle #5Merging (Combining)

2Adaptability or versatility

If signal strength detection and automatic gain control are implemented, then dynamic range processing is improved, but circuit complexity increases

Engineering Contradiction:
Improvedynamic range processingVSAvoidcircuit complexity
Core Design Contradiction:
Adaptability or versatilityVSDevice complexity

Solution Approach 1:

The signal strength detector and signaling circuit are integrated within the amplifier circuit itself, merging multiple functions (amplification, signal strength detection, gain control, and gain information signaling) into a single integrated circuit. This consolidation reduces overall system complexity despite adding advanced functionality

Inventive Principle:
Principle #5Merging (Combining)

Solution Approach 2:

The amplifier circuit performs self-diagnosis and self-signaling by automatically detecting its own gain setting and communicating this information through the output terminal. The circuit monitors its internal state and externally signals this information without requiring additional control circuits or external monitoring components

Inventive Principle:
Principle #25Self-service

Data Source

PatentEP3347985B1Integrated circuit, circuit assembly and a method for its operation
Publication Date: 2023.07.19 TDK CORP
  • EP3347985B1 patent drawingFigure 1A~1B
  • EP3347985B1 patent drawingFigure 1C~2A
  • EP3347985B1 patent drawingFigure 2B~3A

AI summary

The present invention relates to an integrated circuit comprising at least one supply voltage terminal (262) configured to receive a supply voltage for operation of the integrated circuit, at least one input terminal (122, 124, 222) configured to receive an analog input signal corresponding to an audio signal, and at least one output terminal (132, 134, 232) configured to provide an analog output signal. The integrated circuit further comprises a signal strength detector configured to detect the signal strength of the analog input signal. The integrated circuit is configured to amplify the audio signal based on the detected signal strength and to output a corresponding amplified signal at the at least one output terminal (132, 134), and a signaling circuit configured to indicate an amplification setting of the integrated circuit at the at least one supply voltage terminal (262) or the at least one output terminal (132, 134, 232). The invention further relates to a circuit assembly (100, 200, 300) comprising a signal source (110), a signal processing device (190, 390) and an amplification circuit and a method for operating such a circuit assembly (100, 200, 300).