Semiconductor Device Equipotential Temperature Sensing

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Solution Overview

Problem

Existing semiconductor devices with temperature sensing diodes face challenges in rapidly detecting temperature variations of power transistors due to electrical isolation, which increases the distance between the diode and the transistor, degrading the response characteristic and preventing effective protection against abrupt heating.

Innovation Solution

The semiconductor device electrically couples the low-potential terminal of a power transistor and the cathode of a temperature sensing diode to have the same potential, eliminating the need for an isolating structure and reducing the distance between them, allowing for more accurate and prompt temperature sensing.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If an isolating structure is provided between the power transistor and the temperature sensing diode to maintain withstand voltage, then electrical isolation and circuit design freedom are improved, but the distance between the power transistor and the temperature sensing diode increases, degrading the response characteristic

Engineering Contradiction:

Improvewithstand voltage maintenanceVSAvoidresponse characteristic

Core Design Contradiction:

ReliabilityVSSpeed

Solution Approach 1:

The invention applies equipotentiality by electrically coupling the low-potential terminal of the power transistor and the cathode of the temperature sensing diode to have the same potential. This eliminates the potential difference between the two components, removing the need for an isolating structure while maintaining electrical safety. The temperature sensing diode can be disposed in the power transistor formation region with minimal distance, achieving rapid temperature detection without requiring insulation barriers.

Inventive Principle:

Principle #12Equipotentiality

2Speed

If the temperature sensing diode is disposed in the power transistor formation region to improve following capability, then temperature sensing response is improved, but an isolating structure must be provided to maintain withstand voltage, which increases distance and degrades response characteristic

Engineering Contradiction:

Improvefollowing capability of temperature sensingVSAvoidisolating structure

Core Design Contradiction:

SpeedVSDevice complexity

Solution Approach 1:

By establishing equipotential connection between the power transistor's low-potential terminal and the temperature sensing diode's cathode, the invention eliminates the need for isolating structures. This allows the temperature sensing diode to be disposed directly in the power transistor formation region with minimal distance, achieving rapid temperature sensing without adding device complexity through insulation structures.

Inventive Principle:

Principle #12Equipotentiality

Solution Approach 2:

The invention merges the electrical potential domains of the power transistor and temperature sensing diode by coupling their low-potential terminals. This consolidation allows both components to share the same potential reference, enabling close physical proximity without electrical isolation, thus simplifying the device structure while maintaining safety.

Inventive Principle:

Principle #5Merging (Combining)

3Adaptability or versatility

If the temperature sensing diode is electrically isolated from the power transistor to improve versatility, then circuit design freedom is improved, but different potentials are applied requiring isolating structures, which increases distance and degrades temperature sensing response

Engineering Contradiction:

Improvecircuit design freedomVSAvoidtemperature sensing response

Core Design Contradiction:

Adaptability or versatilityVSSpeed

Solution Approach 1:

The invention resolves the contradiction between versatility and response speed by applying equipotentiality. By coupling the low-potential terminal of the power transistor and the cathode of the temperature sensing diode to have the same potential, the system gains design freedom (no isolating structures needed) while achieving rapid temperature sensing response through minimal distance between components.

Inventive Principle:

Principle #12Equipotentiality

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 configuration enhances the response characteristic of the temperature sensing diode, enabling timely detection of temperature changes and effective prevention of power transistor breakdown due to heating.

Implementation Method 1

time is required for heat conduction from the power transistor as a heat source to the temperature sensing diode

Methodology Applied

Scientific EffectHeat conduction: Conduction (thermal)

Data Source

PatentUS10192795B2Semiconductor device

Publication Date: 2019.01.29 RENESAS ELECTRONICS CORP

AI summary

A semiconductor device including a power transistor is prevented from being broken. A cathode of a temperature sensing diode and a source of a power MOSFET are electrically coupled to each other so as to have the same potential. Such a characteristic point allows the temperature sensing diode to be disposed in a power MOSFET formation region without considering withstand voltage. This means that there is no need to provide an isolating structure that maintains a withstand voltage between the power MOSFET and the temperature sensing diode. Consequently, the power MOSFET and the temperature sensing diode can be closely disposed.