Amplifying Circuit Switching to Prevent Speaker Unlocking Noise

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Solution Overview

Problem

Existing amplifying circuits for speakers experience 'unlocking' issues, causing abnormal sounds due to simultaneous transistor turn-off during state switching, affecting user experience.

Innovation Solution

An amplifying circuit design with a charging circuit and output circuit, utilizing a sequence of transistor on/off states to prevent simultaneous turn-off, maintaining stable transconductance and avoiding 'unlocking', and a corresponding charging method to control transistor states.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Ease of operation

If transistors alternate turning on in different states for smooth speaker operation, then the speaker can operate smoothly, but all transistors may turn off simultaneously during switching causing unlocking and abnormal sounds

Engineering Contradiction:

Improvesmooth speaker operationVSAvoidtransistor simultaneous turn-off causing unlocking

Core Design Contradiction:

Ease of operationVSReliability

Solution Approach 1:

The patent applies preliminary action by having at least one first transistor and at least one second transistor simultaneously turn on for a predetermined time period before the first transistors turn off. This advance preparation ensures that the output circuit remains connected to the speaker during the transition, preventing the unlocking condition where all transistors would simultaneously be off.

Inventive Principle:

Principle #10Preliminary action

2Productivity

If transistors switch states to charge the target device to predetermined voltage, then charging function is achieved, but unlocking occurs affecting user experience

Engineering Contradiction:

Improvecharging functionVSAvoidabnormal sounds affecting user experience

Core Design Contradiction:

ProductivityVSObject-affected harmful factors

Solution Approach 1:

The patent uses the simultaneous conduction period of both first and second transistors as an intermediary transition state. This intermediate phase acts as a buffer that prevents direct transition from charging mode to output mode, ensuring continuous connection to the speaker and eliminating the harmful unlocking effect that would cause abnormal sounds.

Inventive Principle:

Principle #24Intermediary (Mediator)

3Speed

If transistors turn off simultaneously during state switching, then circuit switching is completed, but total transconductance becomes unstable causing unlocking

Engineering Contradiction:

Improvecircuit switching speedVSAvoidtotal transconductance stability

Core Design Contradiction:

SpeedVSStability of the object's composition

Solution Approach 1:

The patent implements periodic action by introducing a predetermined time period during which both first and second transistors are simultaneously on. This controlled periodic overlap ensures that the transition between charging and output states maintains stable total transconductance, preventing unlocking while still achieving rapid switching.

Inventive Principle:

Principle #19Periodic action

Data Source

PatentUS12587147B2Amplifying circuit and charging method which can improve abnormal sound

Publication Date: 2026.03.24 REALTEK SEMICON CORP

AI summary

An amplifying circuit, comprising: a charging circuit, comprising a plurality of first transistors electrically coupled to a target device; and an output circuit, comprising a plurality of second transistors electrically coupled to the target device. After at least one of the first transistors turns on and the second transistors turn off such that the charging circuit charges the target device to a predetermined voltage, at least one of the first transistors and at least one of the second transistors simultaneously turn on for a predetermined time, and then at least one of the second transistors turns on but the first transistors turns off.