Shunt Resistor Segmentation for Measurement Accuracy
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Solution Overview
Problem
Current shunt resistor configurations face challenges in size reduction and measurement accuracy due to integral detection and current-passing parts, and susceptibility to variations in resistance values caused by connection materials and locations, leading to inaccuracies in current measurement.
Innovation Solution
A shunt resistor design featuring connecting parts affixed to electrodes via conductive adhesive and a bridging part with bonding wires detecting voltage drops, allowing for flexible shape and reduced influence from connection conditions, enhancing measurement accuracy and size reduction possibilities.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If the current-passing part and detection parts are provided integrally, then manufacturing is simplified, but the degree of freedom for the connected-end member is reduced and size reduction becomes difficult
Solution Approach 1:
The shunt resistor is divided into distinct components: a current-passing part (bridging part) and separate detection parts (bonding wires). This segmentation allows the bonding wires to be positioned independently on the lead frame, providing design flexibility and enabling size reduction while keeping the current-passing part simple and manufacturable.
2Ease of manufacture
If the detection parts are formed in one shape, then manufacturing is easier, but the lead frame requires additional space for land pattern, making size reduction infeasible
Solution Approach 1:
By separating the detection function into independent bonding wires rather than forming detection parts as a single integrated structure, the design allows compact arrangement on the lead frame. The bonding wires can be positioned closely together, reducing the required land pattern area and enabling overall device size reduction.
3Reliability
If leg parts are connected to connection targets via connection member such as solder, then connection is achieved, but resistance value varies due to connection conditions, reducing measurement accuracy
Solution Approach 1:
The detection function is extracted from the connection structure. The bonding wires are bonded directly to the bridging part rather than through additional connection members, eliminating the variable resistance introduced by solder joints in the detection path. This ensures that voltage drop measurements reflect only the current-passing part's resistance, improving measurement accuracy.
Solution Approach 2:
The bridging part serves as an intermediary that provides a stable, direct bonding surface for the detection wires. By bonding the detection wires directly to the bridging part rather than through connection members, the design eliminates the resistance variability introduced by intermediate connection layers.
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 ensures higher accuracy in current measurement by minimizing the impact of connection conditions and allowing for more compact device sizes by decoupling detection and current-passing components and reducing noise from magnetic flux.
Implementation Method 1
two connecting parts (10) affixed to the electrodes (200a, 200b) via a conductive adhesive, respectively, and electrically connected to the affixed electrodes
Implementation Method 2
A current value is measured by using a shunt resistor according to a resistance value of a resistive element forming the shunt resistor and a potential difference across the shunt resistor
Data Source
AI summary
A shunt resistor, at least a part of which has a resistive element with pre-set resistivity, is configured to bridge between two electrodes and detect a current value of a current flowing between the electrodes by detecting a voltage drop in the resistive element. The shunt resistor includes two connecting parts affixed to the electrodes via a conductive adhesive, respectively, and the connecting parts electrically connected to the affixed electrodes, a bridging part bridging between the connecting parts by being extended from one of the connecting parts to the other one of the connecting parts, and two bonding wires used to detect a voltage drop in the resistive element. The bonding wires are bonded to the bridging part.