If you’re working with a Switch-Mode Power Supply (SMPS), you’ve probably encountered noisy or unstable outputs. This is a common issue caused by high-frequency switching noise that can interfere with the smooth flow of power to sensitive circuits. Luckily, you can fix this with a well-designed output filter.

The Problem :

When an SMPS operates, it switches rapidly, creating electromagnetic interference (EMI) that can affect your circuit’s performance. This noise can cause unwanted spikes or ripple voltages. The solution? Adding an output filter to smooth the output, reducing noise and ensuring steady, clean power.

Practical Example :

Imagine you’re powering a microcontroller-based project. Without a filter, your microcontroller may experience glitches, or worse, fail to work properly. By using a low-pass filter (a combination of a capacitor and an inductor), you can filter out the high-frequency noise, providing a clean DC voltage to your project.

Sample Calculation :

To calculate the capacitance needed, you can use this formula for a basic low-pass filter:

fc​=2πLC​1​​

Where:

• fc​ is the cutoff frequency (for example, 100 kHz).
• L is the inductance (say, 10 µH).

For a cutoff of 100 kHz, you’ll need a capacitor of around 159 nF.

Product Recommendations :

To build your output filter, you’ll need components like inductors and capacitors. Check out the high-quality, Made in India components available at SmartXProKits. For instance, look for “Inductor” or “Capacitor” on our site:

Shop now at SmartXProKits.in and support India’s innovation—buy components made in India!