Electrical Load Controller Fault Detection via Linear State
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Solution Overview
Problem
Existing fault detection systems for electrical loads require expensive and space-consuming current monitoring circuits and are ineffective in detecting open-circuit faults due to low drain-to-source voltage sensing, especially when the product of on-state current and on-resistance is low, leading to unreliable fault differentiation and high static power dissipation.
Innovation Solution
A controller with a gate-driver and voltage-detector that operates the switching-device in a linear-state to detect voltage-drop across the device, indicating a no-fault condition when the voltage-drop exceeds a threshold for a predetermined interval, thereby avoiding the need for expensive sense resistors and FETs, and allowing for fault detection without disrupting the electrical load.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If current monitoring circuits with sense resistors are used to detect fault conditions, then fault detection capability is improved, but device complexity and cost increase
Solution Approach 1:
The patent extracts the fault detection function from separate external monitoring circuits and integrates it directly into the controller's existing voltage sensing infrastructure. By utilizing the voltage detector already present for other control functions, the system achieves fault detection without adding separate sense resistors or monitoring circuits, thereby reducing device complexity while maintaining reliability.
Solution Approach 2:
The voltage detector is designed to serve multiple functions: it monitors voltage for normal control operations and simultaneously detects fault conditions by analyzing voltage drop patterns during switching transitions. This multi-functionality eliminates the need for dedicated fault detection hardware, reducing overall device complexity while maintaining comprehensive monitoring capability.
2Measurement precision
If external sense elements and signal amplifiers are used for open load condition detection, then fault detection accuracy is improved, but manufacturing cost increases
Solution Approach 1:
The system uses its own existing voltage detector and control signals to perform fault detection, rather than relying on external sense elements. The controller monitors the voltage drop across the switching device during its natural switching transitions, leveraging already-present hardware to achieve accurate fault detection without additional manufacturing costs.
Solution Approach 2:
The patent changes the operational parameters of the switching device temporarily during fault detection by controlling it to transition through the linear state. This parameter change enables the existing voltage detector to measure voltage drop patterns that reveal fault conditions, achieving accurate detection without requiring external sense elements or signal amplifiers.
3Reliability
If the switching-device is operated in linear-state for fault detection, then fault detection capability is improved, but energy consumption increases
Solution Approach 1:
The controller operates the switching device in the linear state periodically or transiently during specific switching transitions to enable voltage drop measurement for fault detection. Rather than maintaining continuous linear operation, the system briefly enters the linear state during controlled transitions, achieving fault detection capability while minimizing energy consumption by limiting linear-state duration to only when necessary for measurement.
4Measurement precision
If high on-resistance solutions are used to enable voltage sensing, then voltage detection sensitivity is improved, but static power dissipation increases
Solution Approach 1:
The patent temporarily changes the resistance parameter of the switching device by controlling it to operate in the linear state during fault detection intervals. This transient parameter change enables sufficient voltage drop for detection without permanently increasing the device's on-resistance, thereby achieving voltage detection sensitivity while avoiding continuous static power dissipation that would result from permanently high resistance.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
Enables reliable detection of short-to-ground and open-circuit conditions without de-energizing the electrical load, reducing static power dissipation and eliminating the need for costly sensing circuitry, while maintaining low on-resistance and allowing for near real-time fault detection.
Implementation Method 1
The voltage-detector is configured to determine a voltage-drop across the switching-device
Data Source
AI summary
A controller configured to detect fault conditions in a circuit that operates an electrical-load includes a gate-driver and a voltage-detector. The gate-driver is configured to control a gate-current to a switching-device. The gate-current is controlled such that the switching-device is operated in a linear-state when the switching-device transitions from an on-state to an off-state. The voltage-detector is configured to determine a voltage-drop across the switching-device. The controller is configured to indicate a no-fault condition when the voltage-drop is greater than a voltage-threshold for more time than a no-fault interval after the switching device is operated from the on-state to the linear-state.