RF Power Amplifier Bias Circuit for Stable Power Mode Switching
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Solution Overview
Problem
Existing radio-frequency modules face instability in output power characteristics when required output power changes, due to difficulties in accurately and rapidly adjusting bias currents, especially with pre-charge circuits that constantly supplement bias currents.
Innovation Solution
A radio-frequency module design featuring two bias circuits connected to a power amplifier, each with a register and current generation circuit to generate bias currents based on digital control signals, allowing for precise adjustment and combination of bias currents to stabilize output power characteristics.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If a pre-charge circuit is added to constantly supplement bias current, then the sensitivity of output power detection is improved, but the ability to rapidly change bias current with high accuracy deteriorates
Solution Approach 1:
The bias circuit is divided into a first bias circuit and a second bias circuit. The first bias circuit generates a first bias current that can be rapidly changed, while the second bias circuit generates a second bias current that compensates for detection sensitivity lack. This segmentation allows each circuit to specialize in one function, resolving the contradiction between rapid response and detection sensitivity.
2Adaptability or versatility
If the bias current is changed to correspond to a large change in required output power, then the adaptability to different power modes is improved, but the accuracy and speed of bias current change deteriorates
Solution Approach 1:
The bias current is segmented into first bias current from the first bias circuit and second bias current from the second bias circuit. The first bias circuit handles rapid changes for different power modes, while the second bias circuit provides precise compensation. This segmentation enables both large-range adaptability and high-precision adjustment.
Solution Approach 2:
The invention changes the parameters of bias current generation by using two separate bias circuits with different characteristics. The first bias circuit is optimized for rapid response, while the second is optimized for precision compensation. By changing how bias current is generated (using multiple sources instead of one), the system achieves both adaptability and precision.
Data Source
AI summary
A radio-frequency module includes a power amplifier, a first bias circuit connected to the power amplifier, and a second bias circuit connected to the power amplifier. The first bias circuit includes a register that receives a first digital control signal corresponding to a power mode of the power amplifier and a current generation circuit that generates, based on information in the register, a first bias current, and the second bias circuit includes another register that receives a second digital control signal corresponding to the power mode and a current generation circuit that generates, based on information in the other register, a second bias current.