Package-Integrated Piezoelectric Current Sensing for Buried Traces
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Solution Overview
Problem
Conventional current sensing methods are ineffective for in-situ measurement of currents in packaged electronic devices, particularly when current conductors are buried or not fully exposed, as they require contact or access that is not feasible in high voltage or noise-sensitive applications, and existing non-contact methods are limited by the need for multiple layers and external components.
Innovation Solution
The development of package-integrated piezoelectric current sensing devices that utilize a hybrid piezoelectric-electromagnetic principle, where released conductive traces within the package substrate are mechanically coupled to piezoelectric stacks, generating a voltage proportional to the current flowing through them in the presence of a magnetic field, allowing for non-contact, localized current sensing without altering the electrical characteristics or design of the system.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If conventional current sensing methods (resistor voltage drop, inductive transducers, Hall effect sensors) are used, then current measurement is possible, but access to the current conductor is required which is not feasible when traces are buried or in high voltage/noise-sensitive applications
Solution Approach 1:
The patent replaces conventional electrical sensing methods (resistor voltage drop, inductive transducers, Hall effect sensors) with a piezoelectric-based sensing mechanism. Instead of directly measuring electrical parameters, the invention uses piezoelectric materials that generate electrical signals in response to mechanical stress caused by electromagnetic forces from the current-carrying trace, enabling non-contact sensing.
Solution Approach 2:
The patent introduces piezoelectric materials as an intermediary between the current-carrying trace and the sensing circuitry. The piezoelectric material acts as a mediator that converts electromagnetic forces from the trace into measurable electrical signals without requiring direct electrical contact with the trace, thus enabling sensing of buried or high-voltage traces.
2Object-affected harmful factors
If non-contact current sensing methods (inductive transducers, Hall effect sensors) are used, then contact with the trace is avoided, but access to surround the current conductor with coil or Hall sensor is required which limits application to at least three layer package with available layers
Solution Approach 1:
The patent merges the piezoelectric sensing structure with the existing package substrate and conductive trace layers. The piezoelectric material is integrated directly onto or near the trace within the same package layers, eliminating the need for separate sensing layers or external components. This merging enables non-contact sensing in two-layer packages and buried trace configurations where traditional methods require additional layers.
3Measurement precision
If conventional sensing methods are used, then current measurement is achieved, but external components or additional layers are required which increases device complexity and manufacturing cost
Solution Approach 1:
The patent creates a universal sensing structure using piezoelectric materials that can sense currents in various configurations (surface traces, buried traces, different layer arrangements) without requiring different sensing mechanisms or additional external components. The same piezoelectric-based structure adapts to multiple sensing scenarios, reducing overall device complexity.
Solution Approach 2:
The patent enables the package substrate itself to perform the sensing function through integrated piezoelectric structures. The sensing capability is built into the package substrate, eliminating the need for external sensing components or additional dedicated sensing layers. The package substrate serves both its structural function and the current sensing function simultaneously.
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
Enables cost-effective, high-volume manufacturable, non-contact current sensing directly integrated into the package substrate, providing accurate measurement of currents without the need for external components, thus overcoming the limitations of existing methods by allowing sensing across internal or inaccessible traces.
Implementation Method 1
the application of stress to a piezoelectric material generates a voltage between electrodes of the piezoelectric material
Implementation Method 2
A magnetic field is applied to the current sensing device which generates an electromagnetic force in response to a current passing through the conductive trace and the magnetic field
Data Source
AI summary
Embodiments of the invention include a current sensing device for sensing current in an organic substrate. The current sensing device includes a released base structure that is positioned in proximity to a cavity of the organic substrate and a piezoelectric film stack that is positioned in proximity to the released base structure. The piezoelectric film stack includes a piezoelectric material in contact with first and second electrodes. A magnetic field is applied to the current sensing device and this causes movement of the released base structure and the piezoelectric stack which induces a voltage (potential difference) between the first and second electrodes.