Switch Mode Power Supplies (SMPS) are efficient and compact, but without proper output overload protection, they can easily be damaged by short circuits or power-hungry loads. For hobbyists and engineers in India, integrating a simple protection mechanism is essential for long-term reliability.

🔧 The Problem: Excessive Load Damages SMPS

When an SMPS powers a device that draws more current than it can safely provide, components like the transformer, switching MOSFET, or output diode may overheat and fail. Overload can occur due to motor inrush currents, faulty circuits, or user mistakes.

✅ The Solution: Add Current Limiting or Foldback Protection

A basic method is to use current sense resistors on the output line to monitor current draw. If the current exceeds a set threshold, a feedback loop or shutdown circuit cuts power. Many modern SMPS ICs also support cycle-by-cycle current limiting.

🔍 Practical Example: 12V SMPS Driving an LED Array

Suppose your 12V SMPS is rated for 2A. You accidentally connect an LED array that draws 3.5A. Without protection, the SMPS overheats. By adding a 0.1Ω resistor on the output and setting a shutdown at 2A, the system safely powers off.

🧮 Sample Calculation: Power on Sense Resistor

At 2A and 0.1Ω:
V = I × R = 2A × 0.1Ω = 0.2V
This voltage can be fed into a comparator or controller input.

🛒 Product Suggestion: Made in India Components

• ⚡ Shop MOSFETs

• 🔧 [Shop resistors]

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