T-Type RF Attenuator Linear-in-dB Temperature Compensation

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Solution Overview

Problem

Conventional RF attenuators used in mobile terminals face challenges in providing a linear-in-dB attenuation response with respect to temperature changes, have limited power handling capacity, and require time-consuming and inconsistent testing processes, while also exhibiting inferior distortion characteristics.

Innovation Solution

The implementation of a T-type RF attenuator circuitry with a control system that adjusts control signals based on temperature or an externally applied test signal to ensure a linear-in-dB attenuation response, allowing for quick and accurate testing and improved power handling with reduced distortion.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If conventional pi-type RF attenuators are used, then temperature compensation can be achieved, but power handling capability is limited and distortion characteristics are inferior

Engineering Contradiction:
Improvetemperature compensationVSAvoidpower handling capability
Core Design Contradiction:
ReliabilityVSPower

Solution Approach 1:

The patent changes the topological structure parameter from conventional pi-type to T-type configuration, which fundamentally alters the impedance transformation characteristics and power distribution within the attenuator, enabling superior power handling while maintaining temperature compensation through modified control signal relationships

Inventive Principle:
Principle #35Parameter changes

2Measurement precision

If conventional testing methods are used, then attenuation response can be measured, but the process is time consuming and exhibits inconsistencies

Engineering Contradiction:
Improveattenuation response measurementVSAvoidtesting time
Core Design Contradiction:
Measurement precisionVSLoss of time

Solution Approach 1:

The control system continuously monitors temperature sensor output and automatically adjusts control signals to maintain linear-in-dB attenuation response across temperature variations, enabling real-time compensation and verification that eliminates time-consuming iterative testing while ensuring measurement consistency

Inventive Principle:
Principle #23Feedback

Solution Approach 2:

The system uses its own temperature sensor and control circuitry to automatically characterize and compensate for its performance, making the device self-testing and self-calibrating, which eliminates the need for external time-consuming test procedures

Inventive Principle:
Principle #25Self-service

3Manufacturing precision

If temperature compensation is implemented, then linear-in-dB response can be achieved, but device complexity increases

Engineering Contradiction:
Improvelinear-in-dB responseVSAvoidcontrol circuitry complexity
Core Design Contradiction:
Manufacturing precisionVSDevice complexity

Solution Approach 1:

The patent modifies the control signal generation approach by using polynomial fitting coefficients stored in lookup tables, which simplifies the real-time computation required for temperature compensation while maintaining high precision linear-in-dB response across the full temperature range

Inventive Principle:
Principle #35Parameter changes

Data Source

PatentUS9385687B2Configurable radio frequency attenuator
Publication Date: 2016.07.05 QORVO US INC

AI summary

RF attenuator circuitry includes an RF attenuator and a control system. The RF attenuator is configured to provide an attenuation response between an input node and an output node. The control system is coupled to the RF attenuator and configured to adjust one or more control signals provided to the RF attenuator based on either the temperature of the circuitry or an externally applied test signal provided to the control system. The control signals are provided such that the attenuation response of the RF attenuator is substantially linear-in-dB with respect to either the temperature or the test signal provided to the control system. Because the control system is configured to adjust the control signals based either on a temperature of the circuitry or the test signal, the response of the RF attenuator can be easily and quickly tested to ensure linear-in-dB operation thereof.