smartxbrains Uncategorized May 10, 2025

The Problem: Overheating in SMPS Circuits

Switched-mode power supplies (SMPS) are efficient, but they can generate heat in components like MOSFETs, diodes, and inductors. If this heat isn’t managed well, it can shorten component life or cause failure. Thermal design isn’t just for industrial engineers—every hobbyist should factor it in!

The Solution: Heat Sinks, Ventilation & Smart Layout

To reduce thermal stress, you can use heat sinks, ensure proper PCB spacing, and optimize airflow. For high-power SMPS, adding a cooling fan and thermal vias under hot components helps spread and remove heat efficiently.

Practical Example: 12V 5A SMPS Project

Let’s say you’re building a 60W (12V × 5A) SMPS for an audio amp. Your switching MOSFET dissipates 3W due to conduction and switching losses. Without a heat sink, its temperature could hit 100°C+. Adding a TO-220 heat sink rated at 20°C/W brings it down to:

ΔT = Power × Thermal Resistance = 3W × 20°C/W = 60°C

So, final temp = 25°C (ambient) + 60°C = 85°C, which is safe.