DC-DC Converter Ground Electrode Pattern Noise Reduction
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Solution Overview
Problem
Existing DC-DC converters in cellular phones face challenges in reducing and preventing switching noise leakage from the ground line due to the common ground electrode pattern, which is not effectively addressed by previous solutions.
Innovation Solution
A DC-DC converter configuration with an insulating substrate featuring a first inductor with magnetic material, a switching control unit, and a ground electrode pattern with a connection electrode pattern of smaller width, which functions as a bead inductor to absorb magnetic flux and reduce noise current leakage.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If a common ground electrode pattern is used to connect the coil, switching IC and other components, then the electrical connection is simplified, but switching noise leaks from the ground line
Solution Approach 1:
The ground electrode pattern is segmented into a first ground electrode connected to the coil and a second ground electrode connected to the switching IC, preventing the noise generated by the switching IC from leaking through the ground line to the coil side
Solution Approach 2:
A capacitor is introduced as an intermediary component connected between the first and second ground electrodes. This capacitor provides a noise filtering function, allowing the segmented ground structure to effectively suppress switching noise while maintaining electrical connectivity
2Ease of operation
If the switching IC is mounted on the surface of the insulator substrate, then the converter functionality is achieved, but the thickness increases
Solution Approach 1:
The design transitions from a three-dimensional stacked configuration to a planar two-dimensional layout. The coil pattern is formed directly on the insulator substrate surface, and all components (capacitors, switching IC) are mounted on the same plane, eliminating the need for vertical stacking and reducing substrate thickness
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
Significantly reduces and prevents noise current leakage from the ground electrode pattern, achieving effective noise reduction without increasing the converter's thickness.
Implementation Method 1
the connection electrode pattern faces the first inductor and has a smaller width in a direction perpendicular or substantially perpendicular to the predetermined direction than the first and second electrode patterns
Implementation Method 2
the first inductor that faces the connection electrode pattern functions as a bead (ferrite bead) and the connection pattern functions as a bead inductor. Hence, the magnetic material of the first inductor absorbs magnetic flux excited by a noise current
Implementation Method 3
loss is generated by the magnetic resistance of the magnetic material such that the noise current is significantly reduced and prevented
Data Source
AI summary
A DC-DC converter includes an insulating substrate with an inductor provided on the top surface thereof, a switching control IC provided therein, and a ground electrode pattern provided on the bottom surface thereof. The ground electrode pattern includes a first pattern and a second pattern separated from each other and a bridge pattern that connects the first and second patterns to each other. A capacitor and the switching control IC is connected to each of the first and second patterns. The bridge pattern faces the inductor and has a smaller width than that of the first and second patterns.