Power Driver Overcurrent Detection With Soft Turn-Off Control
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Solution Overview
Problem
Existing power device drivers fail to accurately detect overcurrent conditions within a short time frame, leading to potential device damage due to hard shutdowns during load short circuits, as the time constant of the filter in the overcurrent monitoring circuit is relatively long.
Innovation Solution
A dual-mode overcurrent protection method is introduced, where a fast detection sub-module quickly monitors the power device state within a preset time period after the input signal becomes inactive, enabling a soft shutdown if overcurrent is detected, and transitioning to hard shutdown if the condition persists beyond the time period.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a filter is used to monitor the voltage VCE of the power device, then the detection is stable and reliable, but the response time is slow due to the relatively long time constant of the filter
Solution Approach 1:
The detection module is segmented into two independent sub-modules: a fast detection sub-module that operates without filtering to provide rapid response, and a filtering sub-module that provides stable and reliable detection. This segmentation allows each sub-module to optimize for its specific function, resolving the contradiction between response speed and detection reliability.
Solution Approach 2:
The system dynamically switches between different detection modes based on the operational state of the power device. When the power device is turning off, the fast detection sub-module is activated to provide rapid response. During normal operation, the filtering sub-module provides stable monitoring. This dynamic adaptation resolves the contradiction by applying the appropriate detection strategy at the right time.
2Reliability
If a soft shutdown is adopted to reduce VCE voltage, then the power device is protected from damage, but the shutdown process takes longer time
Solution Approach 1:
The fast detection sub-module performs preliminary detection of overcurrent conditions during the brief period when the power device is turning off. By detecting overcurrent in advance during this transition period, the system can immediately initiate soft shutdown protection, preventing device damage while minimizing the time loss by catching the condition at the earliest possible moment.
Solution Approach 2:
The patent rushes through the critical detection period by using the fast detection sub-module that operates without filtering. This allows the system to quickly identify overcurrent conditions during the brief off-transition period and immediately activate protection, effectively skipping the delay that would occur with filtered detection and minimizing overall shutdown time.
3Productivity
If the power device is turned off quickly, then productivity is improved, but the VCE voltage becomes excessively large causing device damage
Solution Approach 1:
The system uses feedback from both the fast detection sub-module and the filtering sub-module to monitor the power device state. When overcurrent is detected by either sub-module, the driving module receives feedback to initiate soft shutdown, reducing VCE voltage to protect the device. This feedback mechanism allows quick turn-off while preventing overvoltage damage through real-time monitoring and adaptive control.
Data Source
AI summary
The present application provides a power device driver including a detection module coupled to the power device and configured to detect the state of the power device; a driving module coupled to the detection module and the power device respectively and configured to detect the power of the detection module. As a result, the power device is regulated; wherein the detection module includes a fast detection sub-module configured to detect a state of the power device within a preset time period after the input signal of the driving device is invalid, and controlling the driving module to softly turn off the power device when there is overcurrent. The present application also provides a corresponding power device driving method and electric equipment.