Smart Electronic Switch With Segmented Driver Circuit
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Solution Overview
Problem
Existing electronic circuit breakers, or e-fuses, in automotive applications lack adequate fault tolerance and functional safety, particularly in environments where stringent safety standards like ISO 26262 must be met, due to inadequate driver circuits.
Innovation Solution
A circuit comprising an electronic switch with a monitoring and protection circuit that generates a protection signal based on current sense signals and wire parameters, allowing for the disconnection of the load from the supply when an overload is detected, and includes a supply circuit to maintain operation during voltage drops, enhancing fault tolerance and safety.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If common driver circuits are used in electronic circuit breakers, then the device complexity is reduced, but the fault tolerance and functional safety deteriorate
Solution Approach 1:
The driver circuit is divided into two independent parts: a first driver circuit that controls the electronic switch, and a second driver circuit that controls the protection circuit. This segmentation ensures that a failure in one driver circuit does not affect the other, thereby improving fault tolerance while maintaining manageable complexity through modular design
Solution Approach 2:
The protection circuit is designed to proactively monitor current through sense signals and wire parameters, and automatically disconnect the load when overload conditions are detected. This beforehand cushioning approach prevents damage before it occurs, enhancing functional safety without requiring complex post-failure handling mechanisms
2Use of energy by moving object
If the supply voltage drops below threshold, then energy consumption is reduced, but the operation of protection circuit registers fails
Solution Approach 1:
The supply circuit detects voltage drops below a threshold and preemptively provides temporary supply voltage to the protection circuit registers. This preliminary action ensures that critical data in the registers is maintained even when main supply voltage sags, preventing operation failure while minimizing energy consumption by only activating the temporary supply when necessary
Solution Approach 2:
The supply circuit acts as an intermediary between the main power supply and the protection circuit registers. It buffers and regulates voltage delivery, providing temporary supply voltage when the main supply drops, thereby isolating the registers from voltage fluctuations and ensuring reliable operation without continuous high energy consumption
Data Source
AI summary
A circuit may include an electronic switch that has a load current path coupled between an output node and a supply node and that is configured to connect or disconnect the output node and the supply node in accordance with a drive signal. Further, the circuit includes a monitoring circuit that is configured to receive a current sense signal, which represents the load current passing through the load current path, and that is further configured to determine a protection signal based on the current sense signal, a state of the monitoring circuit, and at least one wire parameter. The wire parameter characterizes a wire that is—during operation—connected to the output node, and the protection signal is indicative of whether to disconnect the output node from supply node. Further, the circuit includes a protection circuit connected to the monitoring circuit.