The Problem :

Automotive Electronic Control Units (ECUs) manage essential vehicle functions. However, accidental reverse polarity during connection can damage these sensitive circuits. Reverse polarity occurs when the positive and negative terminals are swapped, leading to burnt components or permanent failure.

The Solution :

A simple and effective solution is using a Schottky diode or P-channel MOSFET in series with the power line. These components block reverse current, ensuring the ECU stays safe.

Practical Example :

Protecting a Car ECU
Imagine you’re wiring an automotive ECU for a prototype. If the battery terminals are reversed, a surge can fry the circuits. By adding a P-channel MOSFET (e.g., IRF9540) between the power source and the ECU, you create a reverse protection barrier.

Sample Calculation :

To protect with a MOSFET, choose a gate resistor to limit inrush current. If the ECU operates at 12V and requires 2A, a 10Ω resistor can limit the gate charging current to a safe level:

I=RV​=10Ω12V​=1.2A

Product Suggestion :

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