I have some Deep UV LEDs that are about 100$ a piece. They are Very sensitive to voltage spikes, a nano-second spike could destroy one. I am building a USB powered Device with a battery, and I'm concerned that even plugging in the USB device, or turning on the battery could destroy the LEDs. I need to clamp the source current at 20ma.
What can I do to protect these LEDs?
Best Answer
They are not all that sensitive to forward current - 1% duty cycle 200mA.
Reverse voltage is more of a problem with this kind of LED, as I understand it, so any kind of silicon diode across the LED will keep it within the -6V limit. You could use a 1N4148, for example.
The diode will not limit the LED current- to do that you would have to add a limiting circuit in series. It's possible to do this but probably not worthwhile, depending on what you are using to control the current. For example, if you are using a resistor it's unlikely to go short. If you are using a current regulator circuit you can add a series resistor so the current regulator is limited in the damage it can do.