RF Power Amplifier Envelope Tracking at Low Output Power
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Solution Overview
Problem
Current wireless communication apparatuses, such as mobile phones, face challenges in reducing power consumption, especially at low power levels, as existing techniques like envelope tracking mode are not effective at these levels, leading to inefficiencies in high-frequency power amplifiers.
Innovation Solution
A wireless communication apparatus with a power amplifying circuit, a source voltage generating circuit, and a bias control circuit that switches between envelope tracking mode and variable control mode based on output power levels, adjusting source voltage and bias to optimize power consumption, particularly at low power levels.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Use of energy by moving object
If envelope tracking mode is used to improve power added efficiency at low power levels, then power consumption is reduced, but the complexity of the system increases due to additional circuits
Solution Approach 1:
The patent implements dynamic switching between envelope tracking mode and linear mode based on the output power level. The control circuit dynamically adjusts the source voltage and bias current according to the operating conditions, enabling the system to operate in envelope tracking mode at low power levels for improved efficiency while switching to linear mode at high power levels to maintain simplicity and performance.
Solution Approach 2:
The patent changes the operating parameters (source voltage and bias current) based on the output power level. By adjusting these parameters dynamically, the system achieves optimal power added efficiency at different power levels, resolving the contradiction between power consumption reduction and system complexity.
2Device complexity
If fixed source voltage is used to simplify the circuit design, then device complexity is reduced, but power added efficiency deteriorates at low power levels
Solution Approach 1:
The patent employs dynamic control of the source voltage and bias current based on the output power level. Instead of using a fixed source voltage, the system dynamically adjusts these parameters to maintain optimal power added efficiency across different operating conditions, particularly at low power levels where efficiency is most critical.
Solution Approach 2:
The patent changes the source voltage and bias current parameters according to the output power level. This parameter adjustment enables the system to achieve high power added efficiency at low power levels while maintaining manageable circuit complexity through controlled variable operation.
3Reliability
If linear mode is used at all power levels to ensure stable operation, then reliability is improved, but power consumption increases
Solution Approach 1:
The patent implements dynamic mode switching between envelope tracking mode and linear mode based on the output power level. The control circuit dynamically determines the optimal operating mode, enabling the system to use envelope tracking mode at low power levels for reduced power consumption while switching to linear mode at high power levels to maintain stable operation and reliability.
Solution Approach 2:
The patent changes the operating mode and corresponding parameters (source voltage and bias current) based on the output power level. This dynamic parameter adjustment allows the system to achieve both low power consumption at low power levels and stable operation at high power levels, resolving the contradiction between reliability and power consumption.
Data Source
AI summary
A high-frequency signal processing apparatus and a wireless communication apparatus can achieve a decrease in power consumption. For example, when an indicated power level to a high-frequency power amplifier is equal to or greater than a second reference value, envelope tracking is performed by causing a source voltage control circuit to control a high-speed DCDC converter using a detection result of an envelope detecting circuit and causing a bias control circuit to indicate a fixed bias value. The source voltage control circuit and the bias control circuit indicate a source voltage and a bias value decreasing in proportion to a decrease in the indicated power level when the indicated power level is in a range of the second reference value to the first reference value, and indicate a fixed source voltage and a fixed bias value when the indicated power level is less than the first reference value.