Dual-Mode Power Amplifier With Transformer Isolation on a Single MMIC
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Solution Overview
Problem
Dual-mode power amplifiers for LTE and 5G mobile communications face challenges in size and efficiency due to the need for additional circuitry and space when using switches, particularly with the InGaP/GaAs HBT or CMOS processes, which affect impedance matching and overall system size.
Innovation Solution
A dual-mode power amplifier design that includes high-power and low-power amplifiers with transformers for impedance matching, where the first transformer provides infinite impedance to the low-power amplifier in high-power mode and vice versa, using a single MMIC implemented in the InGaP/GaAs HBT process, with transformers configured as microstrip patterns on a PCB.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If a switch is implemented using the InGaP/GaAs HBT process to isolate high-power and low-power amplifiers, then the same process as the power amplifier is used, but there are problems with high loss and the need for additional circuitry for switch on/off bias which requires an additional HBT size, causing problems with the overall system and MMIC size
Solution Approach 1:
The patent merges the functions of the high-power amplifier, low-power amplifier, and switching mechanism into a single MMIC device. The bias control circuit integrates the switching logic that selectively activates either the high-power or low-power amplifier path, eliminating the need for external switches and their associated bias circuitry. This consolidation reduces the overall MMIC size while maintaining dual-mode operation capability.
Solution Approach 2:
The MMIC is designed with universal components that can serve multiple functions. The same amplifier transistors are used in both high-power and low-power modes by controlling their bias conditions. The bias control circuit provides multi-functional control, enabling the system to switch between operating modes and adjust impedance matching networks accordingly, thereby eliminating the need for separate switch components.
2Adaptability or versatility
If a switch is implemented using the CMOS process, then a space is needed to connect an additional switch that can be implemented in a module assembly unit, but it cannot be highly competitive in the communication components market, where an increase in size in micro-meter units may be a major problem in market competition
Solution Approach 1:
The patent combines the high-power and low-power amplifier paths within a single MMIC device, with the bias control circuit integrating the switching functionality. This eliminates the need for external CMOS switches and their associated connection spaces in module assembly units. The compact integrated design maintains dual-mode operation while significantly reducing the overall size, making it highly competitive in the communication components market.
3Power
If transformers are used for impedance matching in dual-mode operation, then maximum output is achieved in both high-power and low-power modes, but the configuration must provide infinite impedance to one amplifier when the other is operating
Solution Approach 1:
The patent employs dynamic impedance matching where the transformer configuration is selectively activated based on the operating mode. When the high-power amplifier is active, the transformer connected to the low-power amplifier path provides high impedance to isolate it. Conversely, when the low-power amplifier operates, the transformer on the high-power path provides high impedance. This dynamic switching of transformer connections enables maximum output in both modes while managing the complexity through controlled isolation.
Solution Approach 2:
The transformers serve as intermediary elements that provide both impedance matching and isolation functions. The transformer connected to each amplifier path acts as an intermediary that matches the impedance to the load when that amplifier is active, while simultaneously providing high impedance to the inactive amplifier path. This intermediary function simplifies the overall configuration by combining matching and isolation in a single component.
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 allows for maximum output in both high-power and low-power modes by optimizing impedance matching, reducing size and increasing efficiency, and minimizing losses, thus addressing the space and efficiency issues in existing dual-mode power amplifiers.
Implementation Method 1
a first transformer connected in series to an output stage of the high-power amplifier... a second transformer connected in series to an output stage of the low-power amplifier... the first transformer may provide impedance matching to the high-power amplifier, and the second transformer may provide an impedance with an infinite value to the low-power amplifier
Data Source
AI summary
The present disclosure relates to a dual-mode power amplifier, there is disclosed a dual-mode power amplifier that can selectively operate in a low-power mode for low output and a high-power mode for high output, the dual-mode power amplifier including a high-power amplifier comprising one or more transistors whose operations are controlled by a first bias; a first transformer connected in series to an output stage of the high-power amplifier; a low-power amplifier comprising one or more transistors whose operations are controlled by a second bias; and a second transformer connected in series to an output stage of the low-power amplifier, wherein the dual-mode power amplifier operates in a high-power mode when the first bias is activated and the second bias is deactivated, and operates in a low-power mode when the first bias is deactivated and the second bias is activated.