Semiconductor Device Ground Fault Protection via Pulse Masking
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Conventional semiconductor devices lack effective ground fault protection, leading to issues such as excess current flow, power loss, abnormal heat generation, and element breakdown when a ground fault occurs at the external terminal.
Innovation Solution
A semiconductor device incorporating a switching output stage, an output control unit, a counter, a logical gate, and a comparator to generate a mask signal and reset signal, which masks the input pulse signal when a ground fault is detected, preventing further switching drive and thus preventing damage.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If ground fault protection is not implemented, then the semiconductor device can operate continuously without interruption, but excess current flows causing power loss, abnormal heat generation, and element breakdown
Solution Approach 1:
The counter counts the number of pulses of the input pulse signal in advance to generate a mask signal before a ground fault can cause damage. This preliminary counting action enables the logical gate to mask the input pulse signal promptly when a ground fault occurs, preventing excess current flow while maintaining a relatively simple circuit structure.
Solution Approach 2:
The mask signal acts as an intermediary between the counter and the input pulse signal. When the counter detects a ground fault condition (by counting pulses without proper termination), it generates a mask signal that the logical gate uses to block the input pulse signal, thereby preventing harmful current flow without requiring direct complex protection circuitry at the power supply terminal.
2Reliability
If masking of input pulse signal is implemented continuously, then ground fault protection is ensured, but normal switching drive operation is interrupted
Solution Approach 1:
The counter generates mask signals periodically based on counting the number of input pulse signals. Rather than continuously masking, the system allows periodic operation where the counter increments with each pulse and generates a mask signal only when the count reaches a predetermined threshold indicating a ground fault condition. This periodic checking mechanism ensures normal operation continues until a fault is detected.
Solution Approach 2:
The system changes the state parameter of the mask signal from low to high only when the counter reaches a specific count value. This parameter change approach allows the system to maintain normal switching drive operation (low mask signal state) and only interrupt operation when necessary (high mask signal state when ground fault is detected), thus balancing productivity and reliability.
Data Source
AI summary
A semiconductor device includes an external terminal, a switching output stage that performs switching drive of a terminal voltage at the external terminal, an output control unit arranged to generate a drive signal for the switching output stage according to an input pulse signal, a counter arranged to count the number of pulses of the input pulse signal so as to generate a mask signal, a logical gate arranged to mask the input pulse signal according to the mask signal, and a comparator arranged to compare the terminal voltage with a predetermined threshold value voltage so as to generate a reset signal of the counter.