On-Package Transformer Power Combiner for CMOS Voltage Limits
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
As CMOS technology advances, the reduced power supply voltage poses a significant challenge for traditional single output power amplifiers in radio transmitters, making it difficult to deliver sufficient power due to limitations in power supply voltage and load impedance.
Innovation Solution
A transformer-based on-package power combiner is implemented, utilizing multiple primary coils connected to power amplifiers and a shared secondary coil to achieve higher power output through electromagnetic coupling, leveraging low-loss dielectric and thick metal layers in silicon packages for efficient power combination.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Power
If a single power amplifier is used in traditional CMOS design, then the device complexity is low, but the power output is insufficient due to reduced power supply voltage
Solution Approach 1:
The power amplifier system is segmented into multiple independent power amplifier units (first PA, second PA, third PA, fourth PA) that operate in parallel. Each PA processes a portion of the input signal independently, and their outputs are subsequently combined through a power combiner to achieve higher total power output while maintaining individual PA simplicity
Solution Approach 2:
Multiple power amplifier outputs are merged through a power combiner structure that integrates the outputs of four separate PAs into a single combined output signal. This merging process achieves higher power output by combining the power from multiple amplifiers while sharing common components such as matching networks and output structures
2Power
If power supply voltage is reduced in advanced CMOS technology, then device integration is improved, but the maximum output power is severely limited
Solution Approach 1:
Instead of relying on a single high-power amplifier that would require high voltage, the system segments the power amplification function into multiple lower-voltage PAs. Each PA operates within the reduced voltage constraints of advanced CMOS technology, but their combined output achieves the required total power level
Solution Approach 2:
The power outputs from multiple voltage-constrained amplifiers are combined through the power combiner to achieve higher total power. This merging allows the system to overcome the individual voltage limitations of each PA while operating within the reduced power supply voltage environment of advanced CMOS nodes
3Power
If discrete power combiners are used, then power combination is achieved, but the device size increases significantly
Solution Approach 1:
The power combiner integrates multiple PA outputs and their matching networks into a single unified structure. By merging the output paths and sharing common components, the design achieves power combination functionality within a compact footprint that is significantly smaller than discrete combiner implementations
Solution Approach 2:
The power combiner structure serves multiple functions simultaneously: it combines power from multiple PAs, provides impedance matching for each PA output, and presents a single matched output to the load. This multi-functionality eliminates the need for separate matching networks and combiner components, reducing overall device size
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 enables reduced power loss, increased design flexibility, and higher power output, overcoming the limitations of traditional power amplifiers by combining power from multiple sources effectively, while maintaining a smaller size and lower loss compared to discrete or on-chip combiners.
Implementation Method 1
utilizing multiple primary coils connected to power amplifiers and a shared secondary coil to achieve higher power output through electromagnetic coupling
Data Source
AI summary
Embodiments are generally directed to a transformer based on-package power combiner. An embodiment of a power combiner includes multiple primary coils on a first metal layer of a package; a secondary coil on a second metal layer of the package, the secondary coil including multiple secondary coil portions, wherein each primary coil is located to be aligned with a respective one of the secondary coil portions; a trace on a third metal layer of the package; and multiple vias to connect the secondary coil portions to the trace on the third metal layer.