MOSFET thermal runaway is a common issue faced by electronics hobbyists and engineers, where a MOSFET (Metal-Oxide-Semiconductor Field-Effect Transistor) overheats and loses control, potentially damaging your circuit. This happens when the temperature of the MOSFET rises, causing it to conduct more current, which in turn generates more heat—a vicious cycle that can ultimately destroy your component.

The Problem :

Imagine you’re working on a simple motor driver circuit, using a MOSFET to switch the motor on and off. If the MOSFET doesn’t have proper heat management, it can start to heat up. The hotter it gets, the more current it draws, causing even more heat. This process is called thermal runaway. Left unchecked, the MOSFET could fail, or worse, damage other parts of your project.

The Solution :

To prevent thermal runaway, you need to manage the heat generated by your MOSFET. Adding a heatsink or fan is one simple and effective solution. Alternatively, using a MOSFET with a higher power rating and ensuring it operates within its safe thermal limits can help.

Practical Example :

Suppose your circuit is driving a 12V DC motor that draws 3A of current. If the MOSFET is not properly rated, it may start heating up beyond its safe operating temperature (e.g., 100°C). A heatsink can help dissipate the heat, keeping the MOSFET at a safe level. Calculating the required heatsink size involves understanding the thermal resistance, but simply choosing a MOSFET with a higher power rating or adding a small fan can be an easy fix.

Sample Calculation :

If your MOSFET dissipates 1W of power, and the thermal resistance of your heatsink is 10°C/W,

The temperature rise will be 10°C, keeping your MOSFET safe from overheating.

Simple but effective!

Shop Now :

To fix MOSFET thermal runaway, you can find quality MOSFETs and heatsinks Made in India at SmartXProKits. Check out products like MOSFET or Heatsink.

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