Gate Driver Output Protection for Short-Circuit Delay Sensing
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Solution Overview
Problem
Conventional gate driver integrated circuits are susceptible to damage from short circuits and heavy capacitive loads due to slow temperature measurement, making them inadequate for protecting high-power drive devices, especially in environments where current sensing is difficult to implement effectively.
Innovation Solution
A gate driver integrated circuit that generates an error signal based on the delay between input and output signal edges, allowing for immediate configuration into a safer operational state to prevent damage, using a logic circuit and counter to estimate long-term average delays and compare them to predetermined thresholds.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If temperature sensing is used to detect short circuit conditions, then some protection from damage is provided, but the response is too slow to react to sudden short circuits
Solution Approach 1:
The patent introduces an intermediary measurement approach by using output signal delay as a proxy indicator of short circuit conditions. Instead of directly measuring temperature (which is slow), the system measures the delay between input and output signal edges, which responds immediately to short circuit conditions. This intermediary measurement enables fast detection while maintaining protection capability.
Solution Approach 2:
The patent replaces the thermal measurement mechanism with an electrical timing mechanism. Temperature sensing relies on thermal diffusion through the semiconductor die, which is inherently slow. The invention substitutes this with an electrical delay measurement that responds instantaneously to short circuit conditions, achieving both speed and reliability.
2Reliability
If current sensing techniques are implemented, then short circuit detection may be improved, but implementation is difficult in high current environments
Solution Approach 1:
The patent uses output signal delay as an intermediary measurement that indirectly indicates short circuit conditions without requiring direct current sensing. This approach avoids the complexity of implementing current mirrors and sensing circuits in high current environments, while still providing reliable short circuit detection through timing measurements.
3Power
If heavy capacitive loads are coupled to the gate driver, then the system may handle higher power demands, but relatively high current flows that may damage the gate driver
Solution Approach 1:
The patent implements preliminary protection by continuously monitoring output signal delay and comparing it against predetermined thresholds before damage occurs. When the delay exceeds the threshold, indicating a potentially damaging heavy load condition, the system proactively enters a protective state by disabling the output driver, preventing damage before it happens.
Solution Approach 2:
The patent employs feedback control by measuring the output signal delay, comparing it to a threshold, and using this information to control the protective state of the gate driver. The delay measurement provides continuous feedback about the load condition, enabling the system to adapt its operation to maintain safety while handling heavy capacitive loads.
Data Source
AI summary
A method for protecting a system including a driver integrated circuit includes receiving a driver input signal. The method includes driving an output signal externally to the driver integrated circuit. The output signal is driven based on the driver input signal and an indication of a delay between receipt of an edge of the driver input signal and arrival of a corresponding edge of the output signal at an output node coupled to a terminal of the driver integrated circuit.