Switching Control Circuit Abnormality Detection
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Solution Overview
Problem
Existing switching control circuits for power devices, such as gate drivers for IGBTs, fail to properly manage turning-off tasks based on the type of abnormalities occurring in the target switching element or its peripheral circuit, potentially causing additional abnormalities when the soft turn-off MOSFET is activated.
Innovation Solution
A switching control circuit with multiple discharge paths of different impedances, each addressing a specific type of abnormality, and a determiner to identify the type of abnormality, ensuring proper turning-off operations by selectively closing and disabling corresponding discharge paths to prevent unexpected switching between them.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If a single discharge path with fixed impedance is used for turning off the target switching element, then the circuit structure is simple, but it cannot properly address different types of abnormalities occurring in the target switching element or peripheral circuit
Solution Approach 1:
The discharge path is segmented into multiple parallel paths (first discharge path with first impedance, second discharge path with second impedance, third discharge path with third impedance) where each path is designed to handle specific abnormality types. The controller selectively activates appropriate discharge paths based on the detected abnormality type, enabling adaptable response without requiring a completely different circuit for each scenario.
Solution Approach 2:
The circuit transitions from a static, fixed-impedance discharge path to a dynamic system where the controller can change the effective impedance by selectively closing different discharge paths based on real-time abnormality detection. This dynamic reconfiguration allows the circuit to adapt its characteristics to match the specific abnormality conditions.
2Reliability
If the soft turn-off MOSFET is activated without considering the type of abnormality, then the turning-off operation can be performed, but additional abnormalities may be caused due to improper turning-off control
Solution Approach 1:
The controller performs preliminary abnormality detection and analysis before activating any discharge path. By identifying the specific type of abnormality first (through the determiner), the controller can select the appropriate discharge path configuration that prevents harmful effects, rather than blindly activating a fixed discharge path that might exacerbate the problem.
Solution Approach 2:
The system incorporates a determiner that continuously monitors the target switching element and peripheral circuit for abnormalities. This feedback mechanism provides real-time information about the abnormality type, allowing the controller to adjust the discharge path configuration dynamically. The feedback loop ensures that the turning-off operation is always matched to the current system state, preventing improper control and additional abnormalities.
3Reliability
If multiple discharge paths with different impedances are provided to address different abnormality types, then proper turning-off control can be achieved, but the device complexity increases
Solution Approach 1:
The controller serves multiple functions: it detects abnormalities, determines abnormality types, selects appropriate discharge paths, and manages the switching elements. This multi-functional controller reduces the need for separate dedicated circuits for each function, consolidating control logic into a single unit that can adaptively manage different discharge paths based on system needs.
Data Source
AI summary
In a switching control circuit, a determiner determines whether there is one of a first type of abnormality and a second type of abnormality different therefrom in a target switching element and/or the switching control circuit. A controller controls a second switching element to close a low-impedance discharge path for discharging a control terminal of the target switching element when it is determined that there is the first type of abnormality, and disables closing of a high-impedance discharge path for discharging the control terminal while the low-impedance discharge path is closed by the second switching element. The controller controls a third switching element to close the high-impedance discharge path when it is determined that there is the second type of abnormality; and disables closing of the low-impedance discharge path while the high-impedance discharge path is closed by the third switching element.