SMPS Overvoltage Protection Design: A Beginner’s Guide for Engineers and Hobbyists

In today’s world of electronics, overvoltage protection in SMPS (Switch-Mode Power Supply) designs is crucial. Overvoltage events can damage sensitive components, disrupt circuits, and even cause fires in extreme cases. Thankfully, protecting your system is relatively simple and cost-effective, even for beginners.

The Problem :

Overvoltage occurs when the voltage supplied to a circuit exceeds the maximum rating of the components. This can happen due to power surges or spikes from the main supply. One effective way to prevent this is by using a clamping diode or a Zener diode. These components will divert the excess voltage to the ground, ensuring your sensitive parts stay safe.

Practical Example:

Imagine you’re building a simple LED circuit with an SMPS. If the supply voltage spikes above the LED’s rated voltage, the LED could burn out. By adding a Zener diode in parallel with the LED, the excess voltage is safely shunted away, protecting the LED from damage.

Sample Calculation:

Let’s say you are using a 12V SMPS to power a 5V circuit.

To protect it, you choose a 5.1V Zener diode with a 1-watt power rating. The current through the Zener diode when the voltage exceeds 5.1V will be:

I=PV=1W5.1V≈0.196AI = \frac{P}{V} = \frac{1W}{5.1V} \approx 0.196AI=VP​=5.1V1W​≈0.196A

This means the Zener diode will conduct up to about 0.196A when the voltage exceeds 5.1V, effectively protecting your circuit.

Enhance Your Prototyping:

Looking for quality prototyping components? Try Zener Diodes and SMPS Modules, Made in India! These reliable components are perfect for your overvoltage protection projects.

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