Programmable Transformer for Power Amplifier Impedance Control
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Solution Overview
Problem
Current radio transmitters face inefficiencies due to the need for different load impedances for high and low power modes, which are not effectively addressed by on-chip LC networks, leading to larger die area, increased cost, and reduced PA efficiency.
Innovation Solution
A transformer with multiple input ports and coil segments is used to dynamically adjust impedance levels by shorting selected turns, allowing a single transformer to optimize power amplifier efficiency for both high and low power modes without the need for additional matching networks.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If on-chip LC networks are used to provide different impedance levels, then impedance adjustment capability is improved, but die area increases and PA efficiency decreases
Solution Approach 1:
The patent merges the impedance adjustment function into the transformer structure itself by adding a control port that can short selected turns of the primary winding. This combines what were previously separate functions (impedance adjustment and power transformation) into a single integrated component, eliminating the need for separate on-chip LC networks and reducing overall die area.
Solution Approach 2:
The transformer is designed to perform multiple functions: power transformation and impedance adjustment. By making the transformer multi-functional through the addition of the control port and selectable turn configuration, it eliminates the need for separate impedance matching networks, thereby reducing die area while maintaining impedance adjustment capability.
2Adaptability or versatility
If on-chip LC networks are used to provide different impedance levels, then impedance adjustment capability is improved, but PA efficiency decreases due to higher loss
Solution Approach 1:
The patent merges the impedance adjustment function into the transformer structure itself by adding a control port that can short selected turns of the primary winding. This combines what were previously separate functions (impedance adjustment and power transformation) into a single integrated component, eliminating the need for separate on-chip LC networks and reducing overall die area.
Solution Approach 2:
The patent converts the traditionally harmful effect of transformer leakage inductance into a useful feature by designing the primary winding with selectable turns. The leakage inductance, which was previously a loss mechanism, is now controllably utilized to provide different impedance levels for high and low power modes, thereby improving PA efficiency while maintaining adaptability.
3Adaptability or versatility
If PA power is backed off by gain control for lower power levels, then power level adjustment is achieved, but PA efficiency decreases and battery life is degraded
Solution Approach 1:
The patent implements dynamic impedance adjustment through the control port that can selectively short turns of the primary winding based on power level requirements. This dynamic reconfiguration allows the transformer to adapt its impedance characteristics in real-time, enabling the PA to operate at optimal efficiency across different power levels rather than relying on static gain control.
Solution Approach 2:
The patent changes the electrical parameters of the transformer by selectively shorting different numbers of turns on the primary winding. This parameter change directly alters the turns ratio and impedance transformation ratio, allowing the system to optimize PA efficiency for different power levels by changing the transformer's electrical characteristics rather than simply adjusting gain.
4Device complexity
If a single transformer optimizes for maximum power level, then device complexity is reduced, but PA efficiency is compromised at lower power levels
Solution Approach 1:
The patent implements dynamic impedance adjustment through the control port that can selectively short turns of the primary winding based on power level requirements. This dynamic reconfiguration allows the transformer to adapt its impedance characteristics in real-time, enabling the PA to operate at optimal efficiency across different power levels rather than relying on static gain control.
Solution Approach 2:
The transformer is designed to perform multiple functions: power transformation and impedance adjustment. By making the transformer multi-functional through the addition of the control port and selectable turn configuration, it eliminates the need for separate impedance matching networks, thereby reducing die area while maintaining impedance adjustment capability.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
This solution reduces die area and power consumption while maintaining high PA efficiency across different power levels, improving battery life and reducing signal loss.
Implementation Method 1
a transformer coupled to the first power amplifier and the second power amplifier... the transformer comprises a primary side formed on at least one first metal layer... and a secondary side formed on a second metal layer
Data Source
AI summary
In one aspect, an apparatus includes: a first power amplifier to receive a first voltage signal and to output a first current; a second power amplifier to receive a second voltage signal and to output a second current; and a transformer coupled to the first power amplifier and the second power amplifier. The transformer may have multiple differential input ports to realize a controllable impedance based on a desired output power level.