Diagnosable Reverse-Voltage Protection Switch for High Power Loads
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Solution Overview
Problem
Existing electrical systems fail to protect high-power devices from reverse current damage when batteries are connected improperly, and lack reliable diagnostic capabilities for fault conditions in reverse-voltage protection circuits.
Innovation Solution
A system incorporating a controllable reverse-voltage protection switch with a control terminal, a ground switch, and a bias voltage source, which can diagnose hardware failures by disconnecting the second terminal from the power source, applying a bias voltage, and determining error conditions based on voltage thresholds, while using high-side and low-side switches to manage the load and power source.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a reverse-voltage protection switch is implemented in high-power electrical systems, then the system is protected from reverse current damage, but the complexity of the circuit increases and diagnostic capabilities remain insufficient
Solution Approach 1:
The reverse-voltage protection function is segmented into distinct components: a high-side switch, a low-side switch, and a dedicated diagnostics circuit. This segmentation allows each component to perform its specific function independently, making the overall system more manageable despite the increased complexity. The diagnostics circuit itself is segmented into a ground switch, bias voltage source, and control system that independently tests the protection switch.
Solution Approach 2:
The diagnostics circuit acts as an intermediary between the control system and the reverse-voltage protection switch. It introduces test signals through the ground switch and bias voltage source, and monitors the response to determine the operational status of the protection switch. This intermediary mechanism enables fault detection without requiring direct access to the high-power switching elements.
2Measurement precision
If diagnostic capabilities are added to detect fault conditions in the protection circuit, then fault detection reliability improves, but the device complexity and number of components increase
Solution Approach 1:
The ground switch serves multiple functions: it connects the first terminal to ground during normal operation and also serves as a test signal path during diagnostics. The bias voltage source not only provides operating voltage but also acts as a test signal source when activated by the control system. This multi-functionality reduces the need for separate dedicated test components.
Solution Approach 2:
The reverse-voltage protection switch is tested using its own operational components (ground switch, bias voltage source, control system) rather than requiring external test equipment. The control system activates the ground switch and bias voltage source to generate test conditions, and the protection switch's response is measured to determine its operational status. This self-service approach enables built-in diagnostics without adding external complexity.
Data Source
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AI summary
Systems and methods of diagnosing a condition of a reverse-voltage protection switch (209) in an electric system (200). The electric system includes a power source (207), an electric load (201), and a reverse-voltage protection switch (209) in a series-type configuration. The electric system further includes a ground switch (213) configured to selectively connect the source terminal of the reverse-voltage protection circuit to ground. The terminals of the reverse-voltage protection circuit are disconnected from the power source. The ground switch is closed to connect one terminal of the reverse- voltage protection switch to ground. A bias voltage is applied to the other terminal of the reverse-voltage protection switch and the reverse-voltage protection switch is opened. An improper short-circuit condition across the reverse-voltage protection switch is detected when the voltage at the biased terminal of the reverse-voltage protection switch is less than a threshold when the reverse-voltage protection switch is opened.