Transmission Circuit Feedback Control for Power Amplifier Protection

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Solution Overview

Problem

Conventional transmission circuits face damage due to high voltage input signals, which can break the thin oxide layer in power amplifiers, leading to circuit unavailability.

Innovation Solution

A transmission circuit with a power amplifier, a pre-stage circuit, and a signal strength adjusting circuit that includes a conversion circuit, a determination circuit, and a processing circuit to convert output signal voltage into an operation value, calculate differential values, and adjust input signals to maintain target power levels, preventing power amplifier damage.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Power

If the power amplifier receives high voltage input signal, then the output signal power can be increased, but the oxide layer in the transistor can be easily broken causing damage to the power amplifier

Engineering Contradiction:

Improveoutput signal powerVSAvoidpower amplifier reliability

Core Design Contradiction:

PowerVSReliability

Solution Approach 1:

The patent implements a feedback mechanism where the processing circuit continuously monitors the output signal power and adjusts the input signal strength accordingly. The conversion circuit converts the output signal strength to an operation value, which is then used by the processing circuit to calculate the appropriate input signal adjustment, ensuring the output remains within safe limits while maximizing power output.

Inventive Principle:

Principle #23Feedback

Solution Approach 2:

The patent applies preliminary action by adjusting the input signal strength before it reaches the power amplifier. The processing circuit pre-calculates the required input signal level based on the target output power and current conditions, preventing the oxide layer breakdown before it occurs rather than reacting after damage happens.

Inventive Principle:

Principle #10Preliminary action

2Stability of the object's composition

If the input signal strength is increased to maintain target output power, then the output power stability is improved, but the risk of exceeding maximum voltage and damaging the power amplifier increases

Engineering Contradiction:

Improveoutput power stabilityVSAvoidvoltage overload damage

Core Design Contradiction:

Stability of the object's compositionVSObject-affected harmful factors

Solution Approach 1:

The feedback mechanism monitors both the output power level and adjusts the input signal accordingly. The processing circuit receives the operation value from the conversion circuit, compares it with target values, and dynamically adjusts the input signal strength to maintain stable output power while preventing voltage overload conditions.

Inventive Principle:

Principle #23Feedback

Solution Approach 2:

The system dynamically adjusts the input signal strength based on real-time conditions rather than using a fixed setting. The processing circuit continuously modifies the input signal level according to the calculated differential value, enabling the system to adapt to changing conditions while maintaining safety margins.

Inventive Principle:

Principle #15Dynamics

3Reliability

If a signal strength adjusting circuit is added to control input signal power, then the power amplifier protection is improved, but the device complexity increases

Engineering Contradiction:

Improvepower amplifier protectionVSAvoidcircuit complexity

Core Design Contradiction:

ReliabilityVSDevice complexity

Solution Approach 1:

The processing circuit serves multiple functions: it converts the operation value, calculates the differential value, determines the adjusted input signal strength, and controls the power amplifier input. By making the processing circuit multi-functional, the patent reduces the need for separate dedicated components for each function, thereby limiting the increase in overall device complexity.

Inventive Principle:

Principle #6Universality (Multi-functionality)

Solution Approach 2:

The patent merges the conversion circuit, determination circuit, and control functions into an integrated signal strength adjusting circuit. This consolidation approach combines multiple protective and control functions into a unified structure, achieving comprehensive power amplifier protection while minimizing the increase in device complexity through functional integration.

Inventive Principle:

Principle #5Merging (Combining)

Data Source

PatentUS11558020B2Transmission circuit and transmission signal strength adjusting method thereof

Publication Date: 2023.01.17 REALTEK SEMICON CORP

AI summary

A transmission circuit includes a power amplifier, a power amplifier forestage circuit and a signal strength adjusting circuit. The power amplifier is configured to amplify an input signal to output an output signal. The power amplifier forestage circuit is configured to output the input signal. The signal strength adjusting circuit includes a conversion circuit, a processing circuit and a storage unit. The conversion circuit is configured to convert the voltage of the output signal into an operation value. The processing circuit is configured to perform an operation according to a target index value stored by the storage unit and the operation value to obtain a differential value. The processing circuit is further configured to adjust the input signal outputted by the power amplifier forestage circuit according to the differential value, so that the power of the output signal is maintained at a target power value.