Power Amplifier Bias Circuit for Fast TDD Startup Response
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Solution Overview
Problem
Conventional power amplifier devices in time division duplexing (TDD) methods require faster response speeds, particularly in reaching a steady state quickly during startup, which existing technologies have not adequately addressed.
Innovation Solution
A power amplifier device with a bias circuit generating startup current based on internal and startup voltages during startup, transitioning to bias current after steady state, and a startup circuit supplying the necessary voltage, utilizing transistors, resistors, and diode-connected transistors to manage these currents and voltages efficiently.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Speed
If a conventional power amplifier is used in TDD method, then the device can communicate with multiple users at the same frequency by dividing communications time, but the response speed is insufficient and the amplifier cannot quickly reach steady state during startup
Solution Approach 1:
The bias current is dynamically adjusted based on the operating state of the power amplifier. During startup, a first bias current is supplied to quickly reach steady state, and during normal operation, a second bias current is supplied. This dynamic adjustment of bias current enables the amplifier to respond faster during startup while maintaining efficient operation during steady state.
Solution Approach 2:
The bias circuit changes the bias current parameter according to different operating phases. By switching between different bias current values (first bias current during startup, second bias current during normal operation), the system optimizes both startup speed and operational efficiency. The bias circuit monitors the operating state and adjusts the bias current parameter accordingly.
2Speed
If the bias current is increased to improve response speed, then the amplifier reaches steady state faster, but the power consumption increases
Solution Approach 1:
The bias circuit applies periodic action by supplying different bias currents at different times. During startup phase, a higher first bias current is supplied to achieve fast response. Once steady state is reached, the bias circuit switches to a lower second bias current for normal operation. This time-based periodic adjustment of bias current ensures fast startup without excessive power consumption during steady operation.
Solution Approach 2:
The system dynamically adjusts the bias current based on operational phase. The bias circuit detects whether the amplifier is in startup or normal operation mode and accordingly supplies the appropriate bias current level. This dynamic adaptation allows the system to optimize the balance between response speed and power consumption at different operational stages.
Data Source
AI summary
A power amplifier device includes a bias circuit to generate a startup current, which is based on an internal voltage and a startup voltage, during a startup time prior to a steady driving time point, and to generate a bias current, which is based on the internal voltage, after the steady driving time point, and a startup circuit to supply the bias circuit with the startup voltage during the startup time.