Semiconductor Device Integrating Fault Detection Circuit
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Solution Overview
Problem
Existing semiconductor devices for power electronics require external high-voltage resistant diodes and additional components for overcurrent detection, leading to increased size and cost due to the need for external components like diodes and capacitors.
Innovation Solution
A semiconductor device with a built-in fault detection circuit using a sense MOS transistor that eliminates the need for external diodes and capacitors by directly detecting overcurrent through a floating terminal and sense node, integrated within the semiconductor chip.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If external high-voltage resistant diodes and capacitors are used for overcurrent detection, then overcurrent detection function is achieved, but device size and cost increase
Solution Approach 1:
The patent merges the overcurrent detection function with the existing semiconductor device structure by utilizing the collector terminal and emitter terminal of the IGBT itself as detection points. The detection circuit is integrated within the semiconductor chip, combining multiple functions (power switching and fault detection) into a single device, thereby eliminating the need for separate external detection components.
Solution Approach 2:
The semiconductor device is designed to perform multiple functions: the IGBT serves both as a power switching element and as a source of detection signals for overcurrent protection. The emitter terminal, originally just a connection point, becomes a dual-purpose element that both carries current and provides the detection voltage signal for fault detection.
2Reliability
If external high-voltage resistant diodes and capacitors are used for overcurrent detection, then overcurrent detection function is achieved, but device cost increases
Solution Approach 1:
The patent merges the overcurrent detection function with the existing semiconductor device structure by utilizing the collector terminal and emitter terminal of the IGBT itself as detection points. The detection circuit is integrated within the semiconductor chip, combining multiple functions (power switching and fault detection) into a single device, thereby eliminating the need for separate external detection components.
Solution Approach 2:
The patent extracts the overcurrent detection function from external components and relocates it directly into the semiconductor device. By taking out the detection requirement from the external component list and implementing it within the chip, the invention eliminates the need for separate high-voltage resistant diodes and capacitors, thereby reducing component count and overall device cost.
3Reliability
If a terminal for voltage detection is added to the driver IC, then overcurrent detection capability is improved, but device complexity increases
Solution Approach 1:
The semiconductor device is designed to perform multiple functions: the IGBT serves both as a power switching element and as a source of detection signals for overcurrent protection. The emitter terminal, originally just a connection point, becomes a dual-purpose element that both carries current and provides the detection voltage signal for fault detection.
Solution Approach 2:
The IGBT's own voltage characteristics are utilized for detection purposes. The device essentially detects faults by monitoring its own operational state (the voltage between collector and emitter terminals), eliminating the need for separate detection terminals or external sensing circuits that would increase complexity.
Data Source
AI summary
A driver IC includes a ring-shaped termination area, and a first area and a second area that are respectively arranged outside and inside the termination area on a layout. A sense MOS that is arranged between a floating terminal and a first sense node and is driven at a power supply voltage is formed in the termination area. A fault detection circuit that detects presence of a fault when a voltage of the first sense node is higher than a decision voltage that has been determined in advance in a period of time that a low side driver is driving a low side transistor into an ON state is formed in the first area.