RF Power Amplifier Control Across Envelope Tracking Power Ranges
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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, 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 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 high-speed DC-DC converters consume excessive power and negate the benefits
Solution Approach 1:
The patent divides the power amplification operation into multiple segments: envelope tracking mode for low power levels (below threshold) and conventional linear mode for high power levels (above threshold). This segmentation allows each mode to operate in its optimal efficiency range, preventing the high-speed DC-DC converter from consuming excessive power while still achieving power savings at low output levels where they are most needed.
Solution Approach 2:
The patent dynamically changes the operating parameters of the power amplifier by switching between envelope tracking mode (with variable source voltage) and linear mode (with fixed source voltage) based on the output power level threshold. This parameter change optimizes the balance between power added efficiency and overall power consumption, eliminating the excessive power consumption of high-speed DC-DC converters at high power levels.
2Reliability
If source voltage is increased to maintain linear operation at maximum amplitude, then amplification linearity is ensured, but unnecessary DC power loss occurs at lower output amplitudes
Solution Approach 1:
The patent implements dynamic source voltage control in envelope tracking mode, where the source voltage VDD is adjusted in real-time to match the instantaneous amplitude of the output signal. This dynamic adjustment ensures that the power amplifier maintains linear operation only when necessary (at high amplitudes) while reducing or disabling the high-speed DC-DC converter at lower amplitudes, thereby eliminating unnecessary DC power loss while preserving amplification linearity when required.
3Use of energy by moving object
If high-speed DC-DC converter is used to track envelope at all power levels, then power added efficiency is improved, but device complexity and power consumption increase
Solution Approach 1:
The patent segments the operating range into low power levels (where envelope tracking is beneficial) and high power levels (where linear mode is more efficient). The high-speed DC-DC converter is activated only in the low power level segment, reducing overall device complexity and power consumption while still achieving power added efficiency improvements where they are most needed.
Solution Approach 2:
The power amplifier is designed to perform multiple functions by switching between envelope tracking mode and linear mode. This multi-functionality allows the same hardware to optimize for power efficiency at low levels while avoiding the complexity and excessive power consumption of continuous envelope tracking at all power levels, making the system adaptable to different operating conditions.
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.