Doherty Power Amplifier Bias Control for Carrier Saturation
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Solution Overview
Problem
Existing Doherty amplifiers cannot control the operation of the carrier amplifier, leading to potential damage due to saturation, which affects efficiency and reliability.
Innovation Solution
A power amplifier module with a carrier control circuit that detects saturation of the carrier amplifier through base current or gate voltage monitoring, allowing for real-time adjustment to prevent damage by modifying the bias point.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Use of energy by moving object
If the carrier amplifier operates at saturation to improve efficiency, then power efficiency is improved, but the carrier amplifier may be damaged due to excessive saturation
Solution Approach 1:
The patent implements a feedback mechanism where the detection circuit monitors the base current of the carrier amplifier and feeds this information to the control circuit. The control circuit then adjusts the bias of the peak amplifier based on the detected saturation state, creating a closed-loop control system that prevents excessive saturation while maintaining efficiency.
Solution Approach 2:
The detection circuit continuously monitors the base current of the carrier amplifier before excessive saturation occurs. By detecting the approach to saturation in advance, the system can preemptively adjust the peak amplifier bias to prevent damage, rather than reacting after damage has occurred.
2Power
If the peak amplifier is controlled based on carrier amplifier saturation detection, then gain characteristics are improved, but the system complexity increases due to additional control circuits
Solution Approach 1:
The detection circuit serves multiple functions: it monitors the base current of the carrier amplifier, detects saturation conditions, and provides feedback signals for control. This multi-functionality reduces the need for separate dedicated circuits for each function, thereby limiting the increase in system complexity.
Solution Approach 2:
The patent combines the detection and control functions into an integrated system where the control circuit receives feedback from the detection circuit and simultaneously manages the peak amplifier bias. This merging of functions reduces the overall number of separate components and simplifies the system architecture.
Data Source
AI summary
A power amplifier module includes a carrier circuit including at least one carrier amplifier; a peak circuit including at least one peak amplifier; a carrier control circuit that controls base current or gate voltage of a certain carrier amplifier in the carrier circuit; and a carrier output circuit that is connected to a carrier amplifier at an output side in the carrier circuit and that supplies a carrier control signal for controlling the base current or the gate voltage of the certain carrier amplifier to the carrier control circuit.