RF Power Amplifier Voltage Biasing for ACLR and Power Trade-Off
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Solution Overview
Problem
Radio-frequency power amplifiers in wireless communications circuitry face a trade-off between power consumption and linearity, with lower supply voltages reducing power consumption but degrading linearity and increasing adjacent channel leakage ratio.
Innovation Solution
A method to determine an optimum supply voltage level for radio-frequency power amplifiers by calculating a cost function that balances adjacent channel leakage ratio margin and current savings ratio, using storage and processing circuitry to adjust power amplifier bias and measure performance metrics across various operating conditions.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Use of energy by moving object
If the supply voltage is lowered to reduce power consumption, then power consumption decreases, but linearity degrades and adjacent channel leakage ratio increases
Solution Approach 1:
The patent applies parameter changes by adjusting the supply voltage to an optimized level that balances power consumption and linearity. Instead of using a fixed low voltage, the system dynamically selects from multiple voltage levels (e.g., 1.8V, 2.0V, 2.2V) based on operating conditions, thereby achieving both power savings and acceptable linearity performance
Solution Approach 2:
The patent implements dynamics by making the supply voltage adjustable and adaptive rather than fixed. The system can dynamically switch between different voltage levels depending on the required output power and linearity demands, allowing optimal performance across varying operating conditions
2Reliability
If the supply voltage is increased to improve amplifier linearity, then linearity improves, but power consumption increases
Solution Approach 1:
The system changes the voltage parameter from a fixed high value to an optimized, variable value. By implementing multiple voltage levels and selecting the appropriate one based on operating conditions, the system achieves good linearity only when necessary, rather than continuously operating at high voltage
Solution Approach 2:
The patent applies partial action by using higher voltage levels only partially—specifically, only when the operating conditions require improved linearity. For normal operations, lower voltage levels are sufficient, and high voltage is activated only when needed, avoiding excessive power consumption
3Power
If multiple power amplifier stages are enabled to increase gain, then gain increases, but power consumption increases
Solution Approach 1:
The system dynamically adjusts the number of active power amplifier stages based on the required gain. Instead of always enabling all stages, the system can switch between different stage configurations (e.g., one stage, two stages, or three stages) to match the actual signal requirements, thereby reducing power consumption when full gain is not needed
Solution Approach 2:
The patent segments the power amplifier into multiple independent stages that can be selectively enabled or disabled. This segmentation allows the system to activate only the necessary number of stages for the current operating condition, optimizing the balance between gain and power consumption
Data Source
AI summary
Electronic devices with wireless communications capabilities are provided. The electronic device may include storage and processing circuitry, power amplifier circuitry, power supply circuitry, etc. The storage and processing circuitry may direct the power amplifier circuitry to operate using a desired gain mode, in a particular radio channel, and at a given output power level. The power supply circuitry may bias the power amplifier circuitry with a power supply voltage. The performance of the power amplifier circuitry may be characterized by an adjacent channel leakage ratio (ACLR) margin. The power consumption of the power amplifier circuitry may be characterized by a current savings ratio. A cost function may be calculated by taking the product of the ACLR margin and current savings ratio. A minimum point for each cost function curve may be determined. It is desirable to bias the power amplifier circuitry with a supply voltage corresponding to the minimum point.