Slim Transformer Core Layout for Leakage Inductance and Low Capacitance
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Solution Overview
Problem
Existing slim-type transformers face challenges in miniaturization while maintaining sufficient leakage inductance and reducing parasitic capacitance, leading to performance deterioration in flat panel display devices.
Innovation Solution
A transformer design incorporating a core unit with symmetrical cores and coils wound in opposite directions, featuring a core shorting unit to reduce parasitic capacitance and a heat dissipation unit to manage heat generation, along with a bobbin for efficient space utilization.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Length of stationary object
If the thickness of the transformer is reduced to meet slim device requirements, then the device thickness is reduced, but leakage inductance becomes very low causing performance fluctuation
Solution Approach 1:
The patent divides the transformer structure into upper and lower cores with multiple leg portions (first and second leg portions with outer legs and center legs). This segmentation allows independent optimization of magnetic paths for different coil windings, enabling sufficient leakage inductance to be achieved within a reduced thickness by creating distinct magnetic flux paths through the separated leg structures.
Solution Approach 2:
The patent transitions from a conventional vertical stacking approach to a planar arrangement with multiple leg portions extending in different directions. The first and second leg portions are arranged side-by-side with spacing portions between them, utilizing horizontal space more effectively. This dimensional reorganization allows the transformer to achieve required inductance values without increasing thickness, as the magnetic paths are distributed across the planar area rather than stacked vertically.
2Length of stationary object
If the distance between the primary coil and the secondary coil is reduced to minimize transformer height, then the transformer height is reduced, but parasitic capacitance increases sharply causing performance deterioration
Solution Approach 1:
The patent introduces spacing portions as intermediary structures between the first and second leg portions. These spacing portions create physical separation and increase the distance between the primary coil (wound around first center leg) and secondary coil (wound around second center leg), thereby reducing parasitic capacitance. The spacing portions act as mediators that maintain electrical isolation while allowing the overall transformer height to remain compact.
Solution Approach 2:
The patent employs asymmetric arrangement where the first and second leg portions are positioned at different locations with spacing portions strategically placed between them. This asymmetric configuration optimizes the distance between primary and secondary coils to minimize parasitic capacitance while maintaining compact dimensions. The unequal spacing and positioning allow for optimized electrical isolation without requiring uniform increases in all dimensional directions.
3Reliability
If a separate inductor is added to secure sufficient leakage inductance, then leakage inductance is improved, but the device complexity and space requirements increase
Solution Approach 1:
The patent merges the functions of the transformer and leakage inductance elements into a single integrated transformer structure. By incorporating multiple leg portions with appropriate coil windings (primary coil around first center leg, secondary coil around second center leg), the transformer itself provides sufficient leakage inductance without requiring a separate inductor component. This integration eliminates the need for additional mounting space and reduces the overall complexity of the power supply unit while maintaining required electrical performance.
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
The design achieves a slim transformer with secured leakage inductance, reduced parasitic capacitance, and improved heat dissipation, enabling a slimmer flat panel display device.
Implementation Method 1
a core unit (110, 210) having an upper core (111, 211) and a lower core (112, 212), and a coil unit (120, 220) disposed in the core unit (110, 210)... a first coil (120) wound in a first direction, a second coil (220) wound in a second direction
Implementation Method 2
A transformer design featuring a core unit with overlapping coils and a core shorting unit to secure leakage inductance and reduce parasitic capacitance
Data Source
AI summary
A transformer according to one embodiment comprises: a core portion having an upper core and a lower core; and a coil portion disposed in the core portion, wherein: the coil portion includes a first coil wound in a first direction, a second coil wound in a second direction opposite to the first direction, and a third coil including a flat panel shape; the lower core includes a body portion, a first leg portion and a second leg portion protruding from the body portion, and a spacing portion formed between the first leg portion and the second leg portion; the first leg portion includes two first outer legs and a first intermediate leg disposed between the two first outer legs; the second leg portion includes two second outer legs and a second intermediate leg disposed between the two second outer legs; the first coil can be disposed to surround the first intermediate leg; and the second coil can be disposed to surround the second intermediate leg.