GaN Transmission Amplifier Preconditioning for TDD Signal Stability
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Solution Overview
Problem
In wireless communication systems using GaN FETs, parasitic phenomena such as current collapse and gate/drain lag lead to unstable drain current, distortion, and delayed transient response, making it difficult to maintain communication quality, especially in TDD systems.
Innovation Solution
A wireless communication apparatus and method that includes a signal processing unit capable of detecting transmission signals and inserting a stabilization signal into the transmission path before the transmission signal. This stabilization signal is designed to stabilize the characteristics of the transmission amplifier, thereby resolving current collapse and gate/drain lag issues.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Power
If a transmission amplifier using GaN FET is operated with large amplitude and large power to achieve higher efficiency and higher power output, then power output and efficiency are improved, but parasitic phenomena such as current collapse and gate/drain lag occur causing unstable drain current and distorted output
Solution Approach 1:
The patent applies preliminary action by inserting a stabilization signal before the main transmission signal to pre-condition the transmission amplifier. The stabilization signal is inserted in a time domain preceding the transmission signal, causing the amplifier to stabilize its characteristics (reducing gate/drain lag and current collapse) before the actual data transmission begins, thereby ensuring stable drain current during high-power operation
2Use of energy by moving object
If the operation class of the transmission amplifier is changed from class A to class AB to class C to aim for higher efficiency, then efficiency is improved, but drain current becomes more unstable due to increased amplitude variations
Solution Approach 1:
The stabilization signal inserted before the transmission signal preconditions the amplifier for high-efficiency operation modes (class AB or class C). By stabilizing the amplifier characteristics in advance, the system can operate in these high-efficiency modes without suffering from drain current instability caused by large amplitude variations
3Manufacturing precision
If digital pre-distortion (DPD) is used to reduce distortion, then distortion characteristics are improved, but performance deteriorates when drain current is unstable due to memory effects
Solution Approach 1:
The patent stabilizes drain current before transmission by inserting a stabilization signal, thereby creating reliable conditions for DPD to function effectively. The stabilization signal reduces gate/drain lag and current collapse in advance, ensuring that the drain current remains stable during the DPD correction process, which enables effective distortion compensation
4Use of energy by moving object
If the transmission amplifier is turned off and on rapidly for TDD operation to reduce power consumption, then power consumption is reduced, but transient response is delayed due to gate/drain lag
Solution Approach 1:
The patent applies preliminary action by inserting a stabilization signal before the transmission signal in TDD operation. This stabilization signal accelerates the transient response by pre-conditioning the amplifier, reducing gate/drain lag effects, and enabling the amplifier to reach steady state faster after rapid on/off switching, thereby maintaining both low power consumption and fast transient response
Data Source
AI summary
An AAS (10) according to the present disclosure includes a signal processing unit (11), a transmitter (12) provided at a stage following the signal processing unit (11), and a transmission amplifier (13) provided at a stage following the transmitter (12). The signal processing unit (11) detects whether there is a transmission signal, and inserts a stabilization signal for stabilizing characteristics of the transmission amplifier (13) in a time domain preceding a time domain of the transmission signal when the transmission signal is detected, so that the stabilization signal passes through the transmitter (12) and the transmission amplifier (13) before the transmission signal passes through the transmitter (12) and the transmission amplifier (13).