The Problem: SMPS Struggles with Sudden Load Changes

Switch Mode Power Supplies (SMPS) are great for efficiency—but when your circuit demands a sudden increase or drop in current (called a load transient), the SMPS can momentarily dip or spike in voltage. This can cause glitches in microcontrollers or reboots in sensitive devices.

The Solution: Tuning with Output Capacitors & Feedback

To handle these load transients smoothly, you need to adjust your SMPS’s feedback loop and add the right mix of low ESR capacitors (like ceramics) at the output. You may also tweak the compensation network (often using resistors and capacitors) to stabilize the response.

Practical Example: ESP32 + Motor Combo

Let’s say you’re powering an ESP32 and a small DC motor from the same SMPS. When the motor kicks in, it draws sudden current, and the ESP32 may crash. Adding 470µF electrolytic + 100nF ceramic caps at the output cushions the dip, while proper feedback tuning prevents overshoot.

Sample Calculation

If your motor load jumps by 500mA in 1µs, and you want to keep voltage dip under 100mV:

Use C ≥ ΔI / ΔV = 0.5A / 0.1V = 5000µF.

Spread across smaller caps to manage ESR.

Product Suggestion: Made in India SMPS Parts

Low ESR Capacitor

MOSFET

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