- #1
- 8,142
- 1,759
One issue I ran across recently involved 24-volt IR LED drivers for IR cameras, in a factory. The LED units were each rated as 0.5 amp loads. The camera was on the same circuit and only pulled about 250 ma. The engineer had specified 2 amp fast-acting fuses to protect the camera circuit and they were popping all over the factory. I investigated and found that we were pulling over 6 amps on each LED driver circuit, on startup. And that was just what I could catch on a meter. The current then dropped to the nominal value.
This particular manufacturer didn't list the inrush current in the specifications which is why our engineer had missed it. I did a little checking and found that LED driver circuits, and particularly IR LED drivers, have high inrush currents that can be as much as 100 times greater than the nominal load.
Technologies exist to limit the inrush in LED circuits. In our case, we were able to exchange the drivers for some that had current limiting.
This particular manufacturer didn't list the inrush current in the specifications which is why our engineer had missed it. I did a little checking and found that LED driver circuits, and particularly IR LED drivers, have high inrush currents that can be as much as 100 times greater than the nominal load.
https://www.ametherm.com/blog/inrush-current/inrush-current-protection-led-lighting-retrofits/Challenge of High Inrush Current
As with any power supply, the LED Driver contains internal capacitors. For the typical LED Driver, the capacitors charge in less than one millisecond after power is turned on. This rapid charging creates https://adlt.com.au/%EF%BB%BFled-driver-inrush-currents/. Compared to older lighting modalities, this is 6 times the inrush current of an incandescent lamp and 4 times the inrush current of the magnetic ballast used in fluorescent lighting.
Technologies exist to limit the inrush in LED circuits. In our case, we were able to exchange the drivers for some that had current limiting.