Smart Electronic Switch Circuit for Automotive Voltage Dip Protection
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Solution Overview
Problem
In automotive applications, a defective load drawing high current can cause a drop in supply voltage, affecting other loads connected to the same power supply, leading to undesired effects and malfunctions.
Innovation Solution
An integrated smart switch circuit with a power transistor and control logic that triggers a switch-off when the load current exceeds a predetermined threshold and the supply voltage falls below a certain threshold, preventing voltage dips and protecting other loads.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a defective load draws high current from the power supply, then the load current increases, but the supply voltage drops affecting other loads
Solution Approach 1:
The control circuit continuously monitors both the load current and supply voltage, and automatically adjusts the power transistor switching state based on the detected conditions. When high current and low voltage are detected simultaneously, the circuit triggers a switch-off to prevent further voltage degradation, thereby stabilizing the power supply for other loads.
Solution Approach 2:
The control circuit acts as an intermediary between the power transistor and the power supply, detecting abnormal conditions (high current combined with low voltage) and mediating the switch-off action to protect the overall system. This intermediary function prevents the defective load from directly impacting other loads connected to the same power supply.
2Reliability
If the smart switch monitors both load current and supply voltage to prevent voltage dips, then the reliability improves, but the device complexity increases
Solution Approach 1:
The control circuit is designed to perform multiple functions: it monitors load current, monitors supply voltage, determines whether switching is required based on combined conditions, and controls the power transistor switching. By consolidating these functions into a single multi-functional control unit, the patent achieves reliable protection while minimizing the increase in device complexity.
Data Source
AI summary
An integrated circuit that may be employed as a smart switch is described herein. In accordance with one embodiment the integrated circuit includes a power transistor coupled between a supply pin and an output pin and further includes a control circuit configured to trigger a switch-on and a switch-off of the power transistor in accordance with an input signal. The control circuit is configured to trigger a switch-off of the power transistor when a load current passing through the power transistor is at or above a predetermined current and a supply voltage received at the supply pin is at or below a predetermined threshold voltage.