Semiconductor Switch Gate Drive Circuit With Unified Failure Detection
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Solution Overview
Problem
Existing drive circuits for semiconductor switching devices face complexity in diagnosing failures and deteriorations, especially in multiple stage or parallel configurations, and cannot effectively predict open failures or maintain appropriate switching characteristics.
Innovation Solution
A drive circuit that includes a control circuit, a gate drive circuit, and a detection circuit. The detection circuit outputs a feedback signal and an adjustment current when the voltage of the high-voltage side main terminal of the semiconductor switching device exceeds a preset threshold, allowing the control circuit to diagnose the state of the device and adjust the gate current accordingly.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If individual detection of collector current, collector-emitter voltage, or emitter-gate voltage is performed for each switching device, then failure diagnosis capability is improved, but circuit configuration becomes complicated
Solution Approach 1:
The patent combines multiple detection functions into a single detection circuit that monitors the voltage between the high-voltage main terminal and the low-potential terminal. This unified approach replaces what would otherwise require separate detection circuits for collector current, collector-emitter voltage, and emitter-gate voltage, thereby simplifying the overall circuit configuration while maintaining comprehensive failure diagnosis capability.
Solution Approach 2:
The detection circuit is designed with multi-functionality, serving as a universal monitoring device that can detect various failure modes (open failure, short failure, deterioration) through a single voltage measurement point. This universal detection mechanism eliminates the need for specialized detection circuits for each parameter, reducing circuit complexity while preserving diagnostic accuracy.
2Device complexity
If voltage Vce is binarized by a both-end voltage detection circuit, then simple detection is achieved, but prediction of open failure and diagnosis of partial failure cannot be performed
Solution Approach 1:
The patent transitions from static binarized voltage detection to dynamic multi-level voltage detection. By monitoring the actual voltage value between the high-voltage main terminal and low-potential terminal during switching operations, the system can dynamically identify different failure stages and types based on voltage characteristics, enabling both simple detection and comprehensive failure prediction.
Solution Approach 2:
The invention changes the detection parameter from binarized voltage (simple on/off state) to continuous voltage value monitoring. This parameter change allows the detection circuit to distinguish between normal operation, partial failure, and complete failure by analyzing voltage magnitude and timing, thereby maintaining circuit simplicity while significantly improving failure prediction and diagnosis capability.
Data Source
AI summary
A detection circuit is provided to output a feedback signal and a adjustment current when a voltage of a high-voltage side main terminal of a semiconductor switching device is equal to or higher than a preset threshold value in a period in which a gate drive circuit turns off the semiconductor switching device to cut off a current, a control circuit diagnoses a state of the semiconductor switching device or controls a signal to be outputted to the gate drive circuit, on the basis of the feedback signal, and a gate current, which is an output of the gate drive circuit, is adjusted by the adjustment current.