Package-Integrated Current Measurement in Power Semiconductors

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Solution Overview

Problem

Bipolar power semiconductor devices like IGBTs require external current measurement devices due to limitations in internal current measurement devices, which increase engineering effort, space, and cost, and lack functional isolation, making them unsuitable for cost-sensitive applications. Additionally, internal current measurement devices fail to isolate sensor signals from steep voltage and current transients.

Innovation Solution

A package-integrated power semiconductor device with a current measurement device electrically insulated and magnetically coupled to the current path, allowing it to sense the magnetic field of the current flowing through the path, and including a thermally conducting insulator and metallic shielding for improved isolation and accuracy.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Measurement precision

If external current sensing elements are used, then current measurement capability is achieved, but engineering effort, space, and cost increase

Engineering Contradiction:

Improvecurrent measurement capabilityVSAvoidengineering effort and space

Core Design Contradiction:

Measurement precisionVSDevice complexity

Solution Approach 1:

The patent merges the current measurement function with the power semiconductor device by integrating a current sensor cell within the device structure. The sensor cell is formed using the same semiconductor substrate and process steps, combining what were previously separate external components into a unified integrated device, thereby reducing engineering effort, space, and cost.

Inventive Principle:

Principle #5Merging (Combining)

Solution Approach 2:

The semiconductor substrate serves multiple functions: it acts as both the power device substrate and the current sensor cell substrate. The same semiconductor material and structure are used for both power switching and current sensing, eliminating the need for separate sensing components and reducing overall device complexity.

Inventive Principle:

Principle #6Universality (Multi-functionality)

2Ease of manufacture

If sensor cells are used in bipolar power semiconductor devices, then integrated current measurement is achieved, but linearity and accuracy are limited

Engineering Contradiction:

Improveintegrated current measurementVSAvoidlinearity and accuracy

Core Design Contradiction:

Ease of manufactureVSMeasurement precision

Solution Approach 1:

The patent applies local quality by creating a dedicated sensor cell region with specific structural characteristics within the semiconductor device. The sensor cell is formed with optimized geometry and material properties in its local region to enhance measurement accuracy and linearity, while the rest of the device maintains its power switching functionality.

Inventive Principle:

Principle #3Local quality

3Device complexity

If internal current measurement devices are used, then device integration is improved, but functional isolation of measurement signal from load current is not achieved

Engineering Contradiction:

Improvedevice integrationVSAvoidfunctional isolation

Core Design Contradiction:

Device complexityVSReliability

Solution Approach 1:

The patent segments the semiconductor device into distinct functional regions: a power device region and a sensor cell region. The sensor cell is electrically isolated from the main power current path through careful design of contact structures and substrate regions, allowing integrated measurement while maintaining functional isolation between the measurement signal and load current.

Inventive Principle:

Principle #1Segmentation

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 low-cost, functionally isolated current measurement within the device package, effectively measuring load current with steep transients and reducing interference, thus addressing the limitations of existing technologies in bipolar devices.

Implementation Method 1

the current path and the current measurement device are arranged so as to enable the current measurement device to sense the magnetic field of a current flowing through the current path

Methodology Applied

Scientific EffectMagnetic field sensing: Magnetic Field

Implementation Method 2

the sensor element may include at least two magneto-resistive elements

Methodology Applied

Scientific EffectMagneto-resistive effect: Magnetoresistance

Data Source

PatentUS11346880B2Power semiconductor device with integrated current measurement

Publication Date: 2022.05.31 INFINEON TECH AUSTRIA AG

AI summary

A package-integrated power semiconductor device is provided, which includes at least one power transistor coupled to a current path, a current measurement device and a package. The current measurement device is electrically insulated from and magnetically coupled to the current path. The current path and the current measurement device are arranged so as to enable the current measurement device to sense the magnetic field of a current flowing through the current path. The at least one power transistor, the current measurement device, and the current path are arranged inside the package. Further, a power module assembly including the package-integrated power semiconductor device as well as a method of operating the package-integrated power semiconductor device are provided.