Multi-Chip Doherty Amplifier With Integrated Power Detection Biasing
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Solution Overview
Problem
Existing Doherty amplifiers require complex off-chip power detection and bias control circuits, leading to increased design and production costs due to the use of different integrated circuits for the class-AB main and class-C auxiliary amplifier stages.
Innovation Solution
A multi-chip Doherty amplifier design utilizing identical MMICs for both stages, with integrated power detection and bias control circuits, allowing for adaptive biasing based on detected RF power levels, simplifying the manufacturing process and reducing costs.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If different integrated circuits are used for the class-AB main and class-C auxiliary amplifier stages with off-chip power detection and bias control circuits, then the amplifier can achieve proper biasing control, but the design and production costs increase due to complexity
Solution Approach 1:
The patent combines the power detection and bias control circuits directly into the MMIC chip itself, merging previously separate off-chip components with the amplifier circuitry. This integration eliminates the need for external power detectors and bias control circuits, reducing overall system complexity while maintaining proper biasing control functionality.
Solution Approach 2:
The MMIC is designed to perform multiple functions: amplification, power detection, and bias control. By making the MMIC universal and self-sufficient, the patent eliminates the need for separate dedicated components for each function, thereby reducing design and production complexity while ensuring reliable operation.
2Ease of manufacture
If identical MMICs are used for both class-AB main and class-C auxiliary amplifier stages with integrated power detection, then manufacturing efficiency improves and costs reduce, but the amplifier must maintain different biasing configurations for each stage
Solution Approach 1:
The patent implements dynamic bias control where the biasing configuration is adjusted based on real-time power detection. The integrated power detectors monitor the actual power levels and automatically adjust the biasing of each MMIC stage accordingly, allowing identical MMICs to adapt to their specific operational roles (class-AB or class-C) during amplifier operation.
Solution Approach 2:
The integrated power detectors provide feedback signals that are used to control the biasing of the amplifier stages. This feedback mechanism allows the system to automatically configure the appropriate biasing mode for each stage based on operating conditions, enabling identical MMICs to function correctly in different amplification modes without requiring manual configuration or different hardware.
Data Source
AI summary
In accordance with an exemplary embodiment of the present invention, a Doherty amplifier is provided for applications in radio frequency, microwave, and other electronic systems. An exemplary Doherty amplifier comprises a first MMIC having a first power detector, and a second MMIC having a second power detector. The first MMIC and the second MMIC are structurally identical. Furthermore, the first MMIC is configured as a carrier amplifier and the second MMIC is configured as a peaking amplifier. In the exemplary embodiment, an amplifier control bias of the carrier amplifier is a function of the power detected by the first power detector and an amplifier control bias of the peaking amplifier is a function of the power detected by the second power detector. The ability to assemble a Doherty amplifier using a single MMIC product results in a simple and less expensive manufacturing process.