Balun Circuit Topology for Odd-Harmonic Emission Reduction
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Existing RF devices face challenges in reducing out-of-band emissions, leading to increased costs and design area requirements due to the inclusion of multiple filters to comply with wireless communication regulations.
Innovation Solution
A balun structure with a transformer topology and capacitors coupled across a primary coil is used to reduce odd-harmonic emissions, allowing for reduced filter size and complexity by introducing zeros at specific frequencies.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Object-generated harmful factors
If multiple on-board filters are included in the signal path to reduce out-of-band emissions, then emissions compliance is improved, but device complexity and design area increase
Solution Approach 1:
The patent combines the filtering function with the existing balun structure by integrating capacitor elements into the balun circuit topology. This merging eliminates the need for separate filter circuits, reducing device complexity while maintaining emission reduction capability. The balun structure itself becomes the filtering mechanism through strategic capacitor placement.
Solution Approach 2:
The balun structure is designed to perform multiple functions simultaneously: impedance transformation and out-of-band emission filtering. By making the balun multi-functional, the patent eliminates dedicated filter components, thereby reducing overall device complexity and design area while achieving both impedance matching and emission control.
2Object-generated harmful factors
If additional inductor-capacitor networks are included to reduce emissions at particular frequencies, then emissions compliance is improved, but device complexity and design area increase
Solution Approach 1:
The patent merges the frequency-selective filtering function into the balun structure itself by strategically placing capacitors within the existing inductor-capacitor network of the balun. This integration eliminates the need for additional separate inductor-capacitor networks, reducing device complexity while achieving targeted frequency emission reduction.
Solution Approach 2:
The balun structure is designed to self-regulate emissions at particular frequencies through its inherent inductor-capacitor topology. The existing components work together to provide frequency-selective filtering without requiring external or additional filtering networks, making the system self-sufficient for emission control.
3Reliability
If multiple filters are included to pass certification specifications, then wireless communication protocol compliance is improved, but manufacturing cost increases
Solution Approach 1:
The patent combines certification-compliant filtering functionality into the existing balun structure, eliminating the need for multiple separate filter components. This reduction in component count directly lowers manufacturing costs while maintaining the emission levels required for wireless communication protocol certification.
Solution Approach 2:
The balun is designed to simultaneously provide impedance transformation and certification-compliant emission filtering. This multi-functionality reduces the total number of components required, thereby reducing bill of materials costs and simplifying the manufacturing process while ensuring protocol compliance.
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 approach effectively attenuates odd-harmonic frequencies, potentially eliminating or simplifying filter circuits, thereby decreasing costs and increasing design area for other components.
Implementation Method 1
a balun structure with a transformer topology and capacitors coupled across a primary coil is used to reduce odd-harmonic emissions
Implementation Method 2
capacitors coupled across a primary coil is used to reduce odd-harmonic emissions, allowing for reduced filter size and complexity by introducing zeros at specific frequencies
Data Source
AI summary
In an embodiment, a circuit includes a first input terminal configured to be coupled to a first terminal of a first capacitor, a second input terminal configured to be coupled to a second terminal of the first capacitor, a balun including a primary inductor and a secondary inductor, and a second capacitor. The primary inductor includes a first terminal coupled to the first input terminal, a second terminal coupled to the second input terminal, a first inductive portion coupled between the first terminal of the primary inductor and a first intermediate terminal, a second inductive portion coupled between the second terminal of the primary inductor and a second intermediate terminal, and a third inductive portion coupled between the first and second intermediate terminals. The secondary inductor includes a first terminal coupled to a ground terminal. The second capacitor is coupled between the first and second intermediate terminals.