Ripple voltage in PFM low current mode.

[BunnyQueen]

Hello, I'm designing an esp32 based board. My current buck converter is AP63202 although I might switch to the AP64062 as 2A is very overkill for this circuit.

The ESP32 is almost the only load on the 3.3v rail aside from the power on LED. it's used to produce PWM for the MOSFET gate drivers in a matter board controlling LED strips.

My concern is that, although it performs well with a load on the 3.3v rail, once the current draw is low the device enters PFM mode. In this mode the output ripple is increased from 25-30mVpp to 60mVpp. I'm worried about this causing issues with my device long term.

Should I simply ignore this ripple at low currents? Is there a good way to overcome this ripple? I have not power profiled the chip yet, but I assume it'll mostly be consuming current in the 20mA range as a matter node, unless it's actively receiving and transmitting data? it'll be probably barely consume any current at night as lights are usually turned off.

[Sprite]

Just spitballing here, but given A. the chip only goes in PFM mode if power usage is low, B. power usage will only be low when the chip doesn't receive/send anything, and C. ripple is important for the analog parts of the ESP32, i.e. the radio receive paths, but not the digital parts... I don't think this would be an issue.

[BunnyQueen]

Just spitballing here, but given A. the chip only goes in PFM mode if power usage is low, B. power usage will only be low when the chip doesn't receive/send anything, and C. ripple is important for the analog parts of the ESP32, i.e. the radio receive paths, but not the digital parts... I don't think this would be an issue.

Thanks. I already improved the design slightly and added bulk capacitors. I hope it'll help. i added an 24uF cap before the MCU