RF Output Circuit With Temperature-Tuned Inductors
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Solution Overview
Problem
Radio frequency circuits in cellular devices face challenges in maintaining high output at high temperatures due to heat-generated degradation of signal transmission characteristics in power amplifiers and filters.
Innovation Solution
The implementation of a radio frequency circuit with a temperature sensor to detect temperature thresholds, and the use of first and second variable inductor circuits with adjustable inductance values to maintain impedance matching and improve signal transmission characteristics at high temperatures.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Power
If the radio frequency circuit operates at high power, then the output signal strength is improved, but the temperature increases causing degradation of signal transmission characteristics
Solution Approach 1:
The patent implements a feedback mechanism where a temperature sensor continuously monitors the temperature of the power amplifier and acoustic wave filter, and a control circuit adjusts the inductance values of variable inductor circuits based on the measured temperature to compensate for signal transmission degradation. This closed-loop feedback system maintains signal quality despite temperature increases during high-power operation.
Solution Approach 2:
The patent changes the inductance parameters of the variable inductor circuits in response to temperature changes. By adjusting the inductance values dynamically based on temperature conditions, the system compensates for the degradation of signal transmission characteristics caused by high temperature, thereby maintaining optimal performance during high-power operation.
2Reliability
If the inductance values are adjusted to compensate for temperature effects, then the signal transmission characteristics are improved, but the circuit complexity increases
Solution Approach 1:
The patent employs dynamic inductor circuits whose inductance values can be adjusted in real-time based on temperature conditions. This dynamic adjustment capability allows the circuit to adapt to changing thermal conditions and maintain reliable signal transmission characteristics without requiring a completely reconfigurable complex circuit architecture.
Solution Approach 2:
The patent introduces variable inductor circuits as intermediary elements between the power amplifier and the acoustic wave filter. These intermediary components provide a controlled means to adjust impedance and compensate for temperature effects, simplifying the overall control mechanism compared to directly modifying the core amplifier or filter circuits.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
This solution enables the radio frequency circuit to maintain high output even at elevated temperatures, thereby improving the Adjacent Leakage Power Ratio (ACLR) and preventing degradation of signal transmission characteristics.
Implementation Method 1
a temperature sensor that measures a temperature of either one or both of the first acoustic wave filter and the power amplifier
Implementation Method 2
a first variable inductor circuit that includes a first inductor disposed in series between the first acoustic wave filter and the antenna connection terminal, and that has a variable inductance value; and a second variable inductor circuit that includes a second inductor connected between the ground and a first path connecting the first acoustic wave filter to the antenna connection terminal, and that has a variable inductance value
Implementation Method 3
the first acoustic wave filter includes one or more surface acoustic wave resonators having an IDT (InterDigital Transducer) electrode
Implementation Method 4
surface acoustic wave resonators having an IDT (InterDigital Transducer) electrode
Data Source
AI summary
A radio frequency circuit includes an antenna connection terminal, an acoustic wave filter, a power amplifier connected to the acoustic wave filter, a temperature sensor that measures the temperature of either one or both of the acoustic wave filter and the power amplifier, a first variable inductor circuit that includes an inductor disposed in series between the acoustic wave filter and the antenna connection terminal and that has a variable inductance value, and a second variable inductor circuit that includes an inductor connected between the ground and a first path connecting the acoustic wave filter to the antenna connection terminal and that has a variable inductance value.