Semiconductor Overvoltage Detection with Dual Resistor Units

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Solution Overview

Problem

Conventional power supply circuits with semiconductor devices fail to detect overvoltage when external resistors for voltage division are disconnected or incorrectly set, leading to potential breakdown of the semiconductor device.

Innovation Solution

A power supply circuit with a dual overvoltage detection unit, utilizing both external and internal resistors to generate multiple divided voltages, which are compared by separate comparators to ensure accurate overvoltage detection and prevent semiconductor device breakdown.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If a single external resistor division method is used for overvoltage detection, then the device complexity is reduced, but the reliability of overvoltage detection deteriorates when external resistors are disconnected or incorrectly set

Engineering Contradiction:
Improveovervoltage detection reliabilityVSAvoiddetection unit complexity
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The overvoltage detection function is segmented into two independent detection units: a first overvoltage detection unit using external resistors and a second overvoltage detection unit using internal resistors. Each unit operates independently to detect overvoltage conditions, ensuring that failure in one unit does not compromise overall detection reliability. This segmentation allows the system to maintain detection capability even when external resistors are disconnected or incorrectly configured.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The invention changes the detection parameter source by providing two different voltage division paths: one using external resistors (first division ratio) and another using internal resistors (second division ratio). By comparing the divided voltages from these two different parameter sources against reference voltages, the system can reliably detect overvoltage conditions regardless of external resistor status, thus improving detection reliability without excessive complexity.

Inventive Principle:
Principle #35Parameter changes

2Ease of manufacture

If external resistors are used for voltage division, then the ease of manufacture is improved, but the measurement precision of overvoltage detection deteriorates when resistors are disconnected or incorrectly set

Engineering Contradiction:
Improvecircuit configuration easeVSAvoidovervoltage detection precision
Core Design Contradiction:
Ease of manufactureVSMeasurement precision

Solution Approach 1:

The semiconductor device incorporates internal resistors and a second overvoltage detection unit as a preliminary backup mechanism. Before external resistor failure occurs, the system is already configured with an alternative detection path using internal resistors. This preliminary action ensures that when external resistors are disconnected or incorrectly set, the measurement precision of overvoltage detection is maintained through the second detection unit, preventing breakdown while preserving ease of manufacture.

Inventive Principle:
Principle #10Preliminary action

3Reliability

If a single overvoltage detection unit is used, then the device complexity is reduced, but the protection capability deteriorates when external resistors are abnormal

Engineering Contradiction:
Improvesemiconductor device protectionVSAvoiddetection system complexity
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The invention implements beforehand cushioning by preparing a second overvoltage detection unit with internal resistors as a backup before external resistor abnormalities occur. This prior cushioning ensures that when external resistors are disconnected, incorrectly set, or fail, the protection capability is maintained through the second detection unit. The dual-unit structure provides a safety cushion that prevents semiconductor device breakdown while managing complexity through systematic redundancy.

Inventive Principle:
Principle #11Beforehand cushioning (Prior cushioning)

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 dual overvoltage detection configuration effectively prevents semiconductor device breakdown by ensuring accurate detection of overvoltage even if external resistors are abnormal, maintaining the semiconductor device within its withstand voltage range.

Implementation Method 1

a first divided voltage after dividing an output voltage of a power supply circuit by first resistors disposed externally

Methodology Applied
Scientific EffectVoltage division: Electrical Resistance

Implementation Method 2

a first comparator arranged to output a first detection signal based on a first divided voltage

Methodology Applied
Scientific EffectComparator operation:

Implementation Method 3

a second divided voltage after dividing the output voltage by the second resistors

Methodology Applied
Scientific EffectVoltage division: Electrical Resistance

Implementation Method 4

a second comparator arranged to output a second detection signal based on a second divided voltage

Methodology Applied
Scientific EffectComparator operation:

Data Source

PatentEP3276830B1Semiconductor device
Publication Date: 2020.12.16 ROHM CO LTD
  • EP3276830B1 patent drawingFigure 1
  • EP3276830B1 patent drawingFigure 2
  • EP3276830B1 patent drawingFigure 3

AI summary

A semiconductor device includes a first overvoltage detection unit including a first comparator arranged to output a first detection signal based on a first divided voltage after dividing an output voltage of a power supply circuit by first resistors disposed externally and a second overvoltage detection unit including second resistors and a second comparator arranged to output a second detection signal based on a second divided voltage after dividing the output voltage by the second resistors.