RF Power Amplifier Envelope Tracking for Low-Power DC Loss
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Solution Overview
Problem
Current wireless communication apparatuses face challenges in reducing power consumption, especially at low power levels, as existing techniques like envelope tracking mode are not effective and result in significant DC power loss, while fixed voltage modes do not achieve substantial power savings.
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/fixed control modes based on output power levels, adjusting source voltage and bias in proportion to power levels to minimize power consumption.
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 DC power loss increases due to unnecessarily high source voltage
Solution Approach 1:
The patent applies dynamics by making the source voltage variable rather than fixed. The source voltage is dynamically adjusted according to the instantaneous power level of the power amplifier, allowing the system to adapt to changing power demands and avoid maintaining unnecessarily high voltage at low power levels, thus reducing DC power loss while maintaining power added efficiency
Solution Approach 2:
The patent changes the parameter of source voltage from a constant value to a variable value that changes with power level. By modifying this key electrical parameter dynamically, the system achieves better energy efficiency at low power levels while preventing excessive DC power loss that would occur with fixed high voltage
2Reliability
If fixed source voltage is used to ensure linear operation, then amplification linearity is maintained, but power consumption increases at low power levels
Solution Approach 1:
The system transitions from static fixed voltage to dynamic variable voltage that adapts to power levels. This dynamic adjustment maintains the minimum voltage required for linear operation at each power level, ensuring amplification linearity is preserved while avoiding the excessive power consumption associated with fixed high voltage operation
3Reliability
If source voltage is increased to maintain linear operation at maximum power, then linearity is ensured, but power loss occurs at lower power levels
Solution Approach 1:
The patent changes the source voltage parameter from a maximum-fixed value to a variable value that scales with power level. This parameter change ensures that the voltage remains sufficient for linear operation at each power level while eliminating the power loss that occurs when maximum voltage is maintained at lower power levels
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.