RF Power Amplifier Mode Switching for Low-Power Efficiency
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Solution Overview
Problem
Current wireless communication apparatuses face challenges in reducing power consumption, particularly at low power levels, as existing techniques like envelope tracking mode are not effective and result in inefficiencies due to high power consumption by high-speed DC-DC converters.
Innovation Solution
A wireless communication apparatus with a power amplifying circuit, source voltage generating circuit, and bias control circuit that switches between envelope tracking mode and variable/fixed control modes based on output power levels, adjusting source voltage and bias in proportion to power levels to optimize power efficiency.
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 components like amplitude detecting circuit and high-speed DC-DC converter
Solution Approach 1:
The patent divides the power amplification system into multiple operational modes (envelope tracking mode and linear mode) with different characteristics. The system segments the power level range into high power levels where envelope tracking is applied and low power levels where linear mode is used, allowing optimization for each segment while managing overall complexity
Solution Approach 2:
The patent dynamically switches between envelope tracking mode and linear mode based on the current power level requirements. This dynamic operation allows the system to adapt its complexity and power consumption characteristics to the actual operating conditions, using the simpler linear mode when possible and the more complex envelope tracking mode only when needed
2Device complexity
If fixed source voltage is used in linear mode, then device simplicity is maintained, but power added efficiency deteriorates at low power levels
Solution Approach 1:
The patent implements dynamic voltage control where the source voltage is adjusted based on the operating mode and power level. In envelope tracking mode, the voltage tracks the signal envelope to maintain efficiency, while in linear mode a fixed voltage is used for simplicity. This dynamic adjustment resolves the contradiction between simplicity and efficiency
Solution Approach 2:
The patent changes the source voltage parameter dynamically based on operating conditions. By switching between fixed voltage (linear mode) and variable tracking voltage (envelope tracking mode), the system optimizes power added efficiency at different power levels while maintaining overall system simplicity through mode-based parameter selection
3Use of energy by moving object
If high-speed DC-DC converter is used for envelope tracking, then power efficiency improves, but the converter itself consumes significant power reducing overall benefits
Solution Approach 1:
The patent segments the power level operating range and applies envelope tracking with DC-DC converter only to high power levels where the efficiency benefits outweigh the converter's power consumption. At low power levels, the system uses linear mode without the DC-DC converter, avoiding the energy loss from the converter while maintaining acceptable efficiency
Solution Approach 2:
The patent dynamically activates or deactivates the DC-DC converter based on the current power level and operating mode. The converter is engaged only when envelope tracking is active at high power levels where it provides net efficiency improvement, and remains inactive at low power levels where its consumption would negate the benefits
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.