Folded Leadframe Opto-Coupler for High Voltage Isolation
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Solution Overview
Problem
Opto-couplers face challenges in achieving sufficient Distance Through Insulation (DTI) to prevent high voltage from damaging components and distorting transmissions on the low voltage side, especially in applications with stringent design rules regarding the distance between high and low voltage circuitry.
Innovation Solution
The opto-coupler design incorporates a folded leadframe configuration, allowing for increased DTI by folding the leadframe one or more times, which can be done in the same plane or across different planes, thereby enhancing the creepage distance and voltage handling capabilities.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a traditional opto-coupler design with a straight leadframe is used, then the device structure is simple and easy to manufacture, but the Distance Through Insulation (DTI) is insufficient to prevent high voltage from damaging components on the low voltage side
Solution Approach 1:
The leadframe is folded one or more times to extend the DTI path from a straight-line distance to a multi-dimensional folded path. This transforms the insulation distance measurement from a single-dimensional linear distance to a multi-dimensional path that travels through folded sections, thereby increasing the effective DTI without proportionally increasing the overall device footprint.
Solution Approach 2:
The folded leadframe design nests the high voltage and low voltage sides within the same compact device envelope by folding the leadframe back on itself. This creates a nested configuration where the insulation path is folded within the device boundaries, achieving extended DTI while maintaining a compact external dimensions.
2Reliability
If the leadframe is folded one or more times to increase DTI, then the insulation distance and voltage handling capability are improved, but the manufacturing process becomes more complex
Solution Approach 1:
The leadframe manufacturing process is segmented into distinct stages: forming the base leadframe structure, folding it to the predetermined configuration, attaching optical components to specific sections, and assembling with the insulation medium. This segmentation allows each step to be optimized independently, making the complex folded structure manageable through standardized sequential operations.
3Reliability
If the folded leadframe design is used to increase DTI in the horizontal aspect, then the creepage distance is enhanced, but the device footprint in the original plane is increased
Solution Approach 1:
The leadframe is folded one or more times to extend the DTI path from a straight-line distance to a multi-dimensional folded path. This transforms the insulation distance measurement from a single-dimensional linear distance to a multi-dimensional path that travels through folded sections, thereby increasing the effective DTI without proportionally increasing the overall device footprint.
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 folded leadframe design effectively increases the DTI, allowing the opto-coupler to operate safely in high-voltage systems without damaging sensitive components, while maintaining efficiency in signal transmission across the insulation gap.
Implementation Method 1
A typical opto-coupler includes a light source, such as a Light Emitting Diode (LED)
Implementation Method 2
a light source, such as a Light Emitting Diode (LED), a photodetector
Implementation Method 3
a light source, such as a Light Emitting Diode (LED), a photodetector
Data Source
AI summary
An optoelectronic device is disclosed. The optoelectronic device may be employed as a single or multi-channel opto-coupler that electrically isolates one circuit from another circuit. The opto-coupler may include one or more folded leads that establish an enhanced isolation gap. The enhanced isolation gap increases the creepage distance of the opto-coupler and increases operational voltages that can be accommodated by the opto-coupler.