Using Step-up regulator U3V40F5 to power a GoPro

I recently bought a U3V40F5 regulator (item #4012) in order to use it with a GoPro 9.
The goal is to increase the autonomy of the camera by powering it with an external li-ion battery pack. The pack consists of 3 li-ion cells in parallel (voltage 3V (discharged) to 4.2V (fully charged); capacity 10500mAh).
I supply the GoPro through the USB-C connector with a regulated 5V. Current consumption is about 500mA while doing nothing and about 700mA while recording in 1080p.

The U3V40F5 has really nice features and seems to be the right choice for this project. However, it does not work, the camera seems to be a too heavy load to power. But theoretically it should be within the announced specifications, so I wonder if I use it correctly.

Below are the results of my first experiments of this item.
I used a lab power supply instead of the battery for the test (3.6V output, 3A current limit).
At start-up, the power supply delivers current between 500mA and 650mA, the output voltage of regulator is a good 5V.
The camera starts, and everything is good for 3 to 4 seconds, then current consumption collapse to 100mA or less, voltage quickly drop to 4.8V and come back to 5V. This causes the GoPro to shutdown.

I tried to add some capacitors (100µF to 220µF) at regulator output but it does not change anything.

Anybody already tried the U3V40F5 in a similar project and have some advices to share ?

Thank you for your help !


700mA should be well withing the capabilities of the U3V40F5, but if the output voltage is dropping, the GoPro might be drawing a large burst of current around 3 to 4 seconds after start-up. Could you try increasing the current limit on your supply or testing with your battery? Could you post pictures of your setup that show all connections?