Dual-Amplifier RF Power Matching Across Power and Frequency Bands
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Solution Overview
Problem
Existing power amplifiers for mobile communication devices face challenges in maintaining high power added efficiency across a wide range of power states and frequency bands, particularly when amplifying RF input signals with multiple frequency bands, leading to decreased efficiency and increased power consumption.
Innovation Solution
A power amplifier configuration that includes a first amplifier with a large element size for high power states and a second amplifier with a small element size for low power states, along with adjustable output matching circuits using inductive and capacitive reactances, allows for impedance matching across different frequency bands, enabling efficient amplification in both high and low power states.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If a single amplifier with fixed element size is used, then the device complexity is reduced, but the power added efficiency deteriorates across different power states and frequency bands
Solution Approach 1:
The power amplifier is divided into multiple amplifying elements (first amplifying element with large element size, second amplifying element with small element size) that can be selectively activated based on power state and frequency band requirements. This segmentation allows each element to be optimized for specific operating conditions, resolving the contradiction between simple configuration and high efficiency across diverse conditions.
Solution Approach 2:
The amplifier configuration dynamically switches between different amplifying elements and output matching circuits based on the operating power state and frequency band. This dynamic adaptation enables the system to maintain optimal power added efficiency across low power, high power, and intermediate power states while handling multiple frequency bands, overcoming the limitation of fixed-element amplifiers.
2Loss of energy
If amplifying elements with different element sizes are used for different power states, then the power added efficiency in low power state and high power state is improved, but the adaptability to multiple frequency bands deteriorates
Solution Approach 1:
Each amplifying element is designed to handle multiple frequency bands, and the output matching circuits are configured to support broad frequency ranges. This multi-functionality ensures that both the first amplifying element (optimized for high power) and the second amplifying element (optimized for low power) can effectively amplify signals across low power, mid power, and high power frequency bands, resolving the contradiction between power state optimization and frequency band adaptability.
Solution Approach 2:
The output matching circuits incorporate adjustable reactive elements (inductors and capacitors) that can be switched based on the operating frequency band. This parameter adjustment capability allows the matching circuits to optimize impedance matching for different frequency bands regardless of which amplifying element is active, thereby maintaining both power added efficiency and frequency band adaptability.
3Device complexity
If fixed output matching circuits are used, then the device complexity is reduced, but the power added efficiency deteriorates when amplifying signals in different frequency bands
Solution Approach 1:
The output matching circuits are designed with switchable reactive elements (inductors L1-L4 and capacitors C1-C4) that can be dynamically configured based on the operating frequency band and power state. This dynamic reconfiguration optimizes the impedance matching for each specific operating condition, maintaining high power added efficiency across low power, mid power, and high power frequency bands without requiring completely separate matching circuits for each band.
Solution Approach 2:
Different sections of the output matching circuits are optimized for different functions: some inductors and capacitors are positioned to provide broadband matching, while others are switchable to provide band-specific optimization. This local quality differentiation allows the matching circuits to achieve both broad frequency coverage and optimized performance for specific frequency bands, resolving the contradiction between circuit simplicity and efficiency across multiple bands.
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 configuration enables power amplification across a wide range of power states and frequency bands, increasing power added efficiency and reducing power consumption, thereby extending talk time in mobile devices.
Implementation Method 1
An inductive reactance is connected between an output of the second output matching circuit and an input of the second output matching circuit
Implementation Method 2
a capacitive reactance is connected between an input of the second output matching circuit and a ground voltage
Data Source
AI summary
A power amplifier includes a first amplifier and a second amplifier which include large and small size elements. An RF input signal is amplified by the first and second amplifiers. An output of the first amplifier is connected to an input of a first output matching circuit. An output of the second amplifier is connected to an input of a second output matching circuit. An output of the second output matching circuit is connected to an RF signal output terminal. In a high power state, the RF input signal is amplified by the first amplifier. In a low power state, the RF input signal is amplified by the second amplifier. In amplification with low power and high frequency, reactances of the second output matching circuit are set at predetermined values. In amplification with low power and low frequency, the reactances of the second output matching circuit are set at larger values.