💡 The Problem :

When using MOSFETs to switch loads, one common risk is over-current—where the load suddenly draws more current than expected. This can heat up the MOSFET, damage your power supply, or even start a fire in extreme cases. Beginners often overlook this, thinking the MOSFET will handle it—but without protection, it won’t.

🛠️ The Solution :

Add an over-current protection circuit using a sense resistor and comparator. When the voltage across the resistor exceeds a set threshold (indicating excess current), the circuit shuts down the MOSFET gate, stopping the current flow instantly.

🔍 Practical Example :

Suppose you’re controlling a 12V LED strip with an IRF540N MOSFET. One day, a short circuit causes the strip to draw 10A instead of 2A. Without protection, the MOSFET overheats and fails.

Fix:
Place a 0.1Ω, 2W resistor in series with the source. Use an op-amp as a comparator to monitor the voltage across it. If it exceeds 0.5V (5A), the op-amp shuts off the MOSFET gate.

🧮 Sample Calculation :

For a 0.1Ω resistor:

If current = 5A,

V=I×R=5A×0.1Ω=0.5V

Set your comparator to trip at 0.5V for over-current shutdown.

🛒 Product Suggestion – Made in India :

Use IRF540N MOSFETs and precision resistors, both available as Made in India components:

🔧 Buy IRF540N MOSFET

🔧 Get 0.1 Ohm Resistor

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