Gate Driver Self-Test Circuit for Power Transistor Protection
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Solution Overview
Problem
Existing drive devices and power supply systems lack a mechanism to test whether protection circuits, such as overvoltage protection circuits, are operating normally, leading to potential damage or degradation of power transistors due to excessive stress conditions like overvoltage, overcurrent, or overheating.
Innovation Solution
Incorporating a sensor to detect stress states, a threshold voltage setting circuit, and an anomaly monitor circuit to determine abnormal stress conditions, with a control circuit that adjusts the power transistor's state and tests the anomaly monitor circuit's functionality by switching the threshold voltage in a test mode.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If protection circuits are added to monitor overvoltage, overcurrent, and overheat conditions, then the safety of power transistors is improved, but the device complexity increases
Solution Approach 1:
The patent combines multiple protection functions (overvoltage protection, overcurrent protection, overheat protection) into a single integrated gate driver circuit. The anomaly monitor circuit integrates multiple sensors and monitoring functions to collectively manage power transistor safety, reducing overall system complexity while maintaining comprehensive protection.
Solution Approach 2:
The gate driver circuit is designed with multi-functionality, serving both as a control circuit for switching power transistors and as a protection circuit through the integrated anomaly monitor. This universal design eliminates the need for separate protection circuits, maintaining safety while controlling complexity.
2Reliability
If testing functions are added to verify protection circuit operation, then the reliability of safety monitoring is improved, but the device complexity increases
Solution Approach 1:
The patent implements preliminary testing of the anomaly monitor circuit during the manufacturing process. By conducting tests before the product reaches the customer, the system verifies that protection circuits function correctly without requiring additional complexity in the final product design. The control circuit is configured to perform self-tests using test signals.
Solution Approach 2:
The gate driver circuit performs self-diagnosis and self-testing through the integrated anomaly monitor. The circuit monitors its own operation and can detect faults in protection functions without requiring external testing equipment, maintaining reliability while minimizing added complexity.
3Measurement precision
If comprehensive stress monitoring is implemented, then the detection precision of abnormal conditions is improved, but the loss of energy increases
Solution Approach 1:
The anomaly monitor circuit performs stress monitoring at critical moments during power transistor operation, such as during switching transitions when stress conditions change most rapidly. This periodic monitoring approach maintains high detection precision for abnormal conditions while minimizing continuous energy consumption compared to constant monitoring.
Data Source
AI summary
A drive device comprises a sensor for detecting a state of stress applied to a power transistor, a threshold voltage setting circuit for outputting a threshold voltage, an anomaly monitor circuit for determining whether or not a state of stress is abnormal by comparing a detected voltage of the sensor with the threshold voltage, and a control circuit for fixing the power transistor to either on or off when the state of stress is determined to be abnormal by the anomaly monitor circuit. When an operating mode is a test mode, the control circuit tests whether the anomaly monitor circuit determines the state of the stress is abnormal or not by switching a level of the threshold voltage set by the threshold voltage setting circuit so as to determine that a state of the stress applied to the power transistor is abnormal in the normally operating anomaly monitor circuit.