Temperature Sensing Diode Protection With Bidirectional ESD Clamping

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Solution Overview

Problem

Existing semiconductor devices lack effective protection against electro-static discharge (ESD) and efficient methods for monitoring temperature and current sensing, which can lead to deterioration of temperature sensing diodes and affect device reliability.

Innovation Solution

A semiconductor device with a bidirectional diode unit connected in a serial bidirectional way between the cathode and anode pads, including a Zener diode for ESD protection, and an output comparison diode unit connected in inverse parallel with the temperature sensing diode for monitoring and determining the service life of the temperature sensing diode.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If a temperature sensing diode is provided without protection, then the device structure remains simple, but the temperature sensing unit is vulnerable to ESD damage and reliability deteriorates

Engineering Contradiction:
Improvetemperature sensing unit reliabilityVSAvoidcircuit structure complexity
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

A bidirectional diode unit is introduced as an intermediary protective element connected in parallel with the temperature sensing diode. This mediator component clamps ESD voltage spikes, protecting the temperature sensing unit from direct damage while maintaining circuit simplicity through a single additional component.

Inventive Principle:
Principle #24Intermediary (Mediator)

Solution Approach 2:

The bidirectional diode unit is pre-configured in parallel with the temperature sensing diode before ESD events occur. This preliminary protective arrangement ensures that when ESD strikes, the protection mechanism is already in place to clamp voltage spikes, preventing damage to the temperature sensing unit.

Inventive Principle:
Principle #10Preliminary action

2Reliability

If the temperature sensing diode is continuously monitored for deterioration, then timely replacement can be achieved, but the monitoring circuit complexity increases

Engineering Contradiction:
Improvetemperature sensing unit reliabilityVSAvoidmonitoring circuit complexity
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

A comparison diode is introduced as a reference copy of the temperature sensing diode's electrical characteristics. By monitoring the voltage difference between the temperature sensing diode and this comparison diode, the system detects deterioration without requiring complex analysis circuits, as the comparison diode provides a stable reference for straightforward voltage differential measurement.

Inventive Principle:
Principle #26Copying

Solution Approach 2:

The monitoring circuit continuously measures the voltage difference between the temperature sensing diode and comparison diode, providing feedback on the temperature sensing diode's health status. When the voltage difference exceeds a threshold indicating deterioration, the system can trigger alerts or automatic replacement procedures, enabling proactive maintenance.

Inventive Principle:
Principle #23Feedback

3Object-affected harmful factors

If protective diodes are added between MOSFET and temperature sensing diode, then ESD protection is improved, but the device area increases

Engineering Contradiction:
ImproveESD protection capabilityVSAvoiddevice area
Core Design Contradiction:
Object-affected harmful factorsVSArea of stationary object

Solution Approach 1:

The bidirectional diode unit serves multiple functions: it protects against both positive and negative ESD voltage spikes, provides voltage clamping, and maintains a compact footprint. This multi-functional protective component replaces what would traditionally require multiple separate protection elements, reducing the overall area required for ESD protection.

Inventive Principle:
Principle #6Universality (Multi-functionality)

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 solution effectively protects the temperature sensing unit from ESD, maintains its characteristics, and allows for timely replacement of the diode, enhancing the semiconductor device's reliability and enabling downsizing while maintaining circuit reliability.

Implementation Method 1

a semiconductor device with a bidirectional diode unit connected in a serial bidirectional way between the cathode and anode pads, including a Zener diode for ESD protection

Methodology Applied
Scientific EffectElectro-static discharge: Electrostatic Discharge

Implementation Method 2

The protection circuit includes multiple Zener diodes connected in series between a gate and an emitter of the power semiconductor element. The protection circuit limits a voltage between the gate and emitter of the power semiconductor element, when an abnormal voltage is applied to the gate.

Methodology Applied
Scientific EffectZener breakdown: Avalanche Breakdown

Implementation Method 3

The temperature sensing unit includes a temperature sensing diode

Methodology Applied
Scientific EffectTemperature-dependent voltage: Thermocouple

Data Source

PatentEP3916805B1Semiconductor device and system
Publication Date: 2023.12.27 FUJI ELECTRIC CO LTD
  • EP3916805B1 patent drawingFigure 1
  • EP3916805B1 patent drawingFigure 2
  • EP3916805B1 patent drawingFigure 3

AI summary

A semiconductor device including: a semiconductor substrate; a temperature sensing unit provided on a front surface of the semiconductor substrate; an anode pad and a cathode pad electrically connected with the temperature sensing unit; a front surface electrode being set to a predetermined reference potential; and a bidirectional diode unit electrically connected in a serial bidirectional way between the cathode pad and the front surface electrode is provided. The output comparison diode unit may be arranged between the anode pad and the cathode pad. The temperature sensing unit may include a temperature sensing diode, and the output comparison diode unit may include a diode connected in inverse parallel to the temperature sensing diode.