Current Sensing Resistor Electrode Layout Without Bonding Wires
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Solution Overview
Problem
Current detection resistors used for detecting large currents face challenges in downsizing due to the need for multiple bonding wires, which increases the size and complexity of the resistor.
Innovation Solution
A current detection resistor design featuring a flat resistive element with conductive metal electrode blocks on both surfaces, where the upper electrode block includes an extension portion that connects to the wiring pattern on a substrate, eliminating the need for bonding wires and allowing for a more compact structure.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Power
If multiple bonding wires are used to connect the terminal for detecting large current, then the current carrying capacity is improved, but the size of the current detection resistor increases
Solution Approach 1:
The patent merges the functions of multiple bonding wires into a single integrated electrode block. The upper electrode block includes an electrode portion connected to the resistive element and an extension portion that extends downward to connect to the wiring pattern, consolidating what would have been multiple separate wire connections into one unified structure. This resolves the contradiction by maintaining the current carrying capacity while eliminating the need for multiple bonding wires, thus reducing the overall size.
Solution Approach 2:
The electrode block serves multiple functions simultaneously: it acts as an electrical connection point for the resistive element, provides structural support, and extends to connect with the wiring pattern on the substrate. This multi-functional design replaces the need for separate bonding wires while maintaining the ability to handle large currents, thereby resolving the size-capacity contradiction.
2Reliability
If the terminal area is increased to accommodate multiple bonding wires, then the current detection capability is improved, but the mountability and compactness deteriorate
Solution Approach 1:
The electrode block extends in the vertical dimension with its extension portion reaching downward toward the wiring pattern on the substrate. This vertical extension allows the terminal to connect to multiple wiring patterns without increasing the horizontal footprint, thus maintaining compactness while preserving current detection capability. The solution moves from a two-dimensional terminal layout to a three-dimensional structure.
3Ease of manufacture
If bonding wires are used for connection, then the manufacturing process is established, but the device complexity and manufacturing cost increase
Solution Approach 1:
The patent combines the electrode block and extension portion into a single integrated component that can be manufactured as one piece. This eliminates the need for separate bonding wire attachment steps, reducing manufacturing complexity while maintaining established manufacturing processes for creating the electrode block itself through techniques like electroplating or sintering.
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 design enables the downsizing of current detection resistors while maintaining the ability to handle large currents, improving mountability and reducing manufacturing costs, and enhancing current detection accuracy by minimizing self-inductance and parasitic inductance.
Implementation Method 1
a first electrode block that is made of a conductive metal material and is laminated on a lower surface of the resistive element; and a second electrode block that is made of a conductive metal material and is laminated on an upper surface of the resistive element
Data Source
AI summary
A shunt resistor 10, 110 includes a flat resistive element 11; a first electrode block 12 that is made of a conductive metal material and is laminated on a lower surface 11a of the resistive element 11; and a second electrode block 13, 113 that is made of a conductive metal material and is laminated on an upper surface 11b of the resistive element 11, in which the second electrode block 13, 113 is a block body including an electrode portion 14 connected to the resistive element 11 and an extension portion 15, 115 extending downward from a side surface of the electrode portion 14.