The USB lamps are very useful, they are easy to connect to USB ports such as laptop, chargers, power banks etc providing light for keyboards at night, room light, night light, reading light etc
There are many types of USB Lamps in the market, cheaper and expensive ones. The USB lamps work with 5V supply, because generally, USB ports only provide 5V supply
The problem with most or cheaper versions of USB Lamps is the LEDs get dimmer or burned faster than usual. We will look how it can be fixed with a simple step.
Why the LEDs of USB lamps get dim or LEDs get burned faster than usual?
The reason for the short lifespan of LEDs on the USB lamps are because they get overdriven with excess current that can damage them overtime or in short time.
The reason why the USB lamp manufacturers overdriving the LEDs are because if they drive them with excess current, the lamps will be brighter and people want to buy brighter lamps, it’s just business and the limitations of electronics to make it cheaper
How to fix the USB lamp’s short lifespan?
I have fixed a cheap USB lamp by adding a 15 ohms resistor on the positive connection of the LED panel, the result is great.
Previously, the same lamps would get hot and fail in a few weeks, but the one i fixed now has been giving me light for months now and it doesn’t get hot
I use it as a night lamp in my bedroom and it works Night to Dawn without an issue. By the dawn, it gets a little hot, but it is acceptable as it has been running all night on my power bank, below is the picture of the lamp that i use now with a 15 ohms resistor.

Img credit: AliExpress
So it is advised by me that you should do the same in your LED lamp to make it last longer, But you should know that if your lamp is not the same like mine, you will need use a different ohms resistor.