So I'm currently working on a project where I need an IR camera with two IR Leds attached to it.
The camera looks something like this:
https://rads.stackoverflow.com/amzn/click/com/B01ICLLOZ8
These LEDS are powered by the camera board an run on 3V with up to 0.3A per LED. Because these LEDS get very hot over time I only want them on power when I really need them. To do this I bought this logic level Mosfet:
https://www.arrow.com/en/products/ipb048n15n5lfatma1/infineon-technologies-ag
IPB048N15N5LFATMA1 by Infineon Technologies AG which should have a gate
threshhold voltage of 3.3V according to the datasheet.
But when I connect the wires to the mosfet, the LED won't turn on. The Drain-Gate Voltage is About 2,7V, the Gate-Source Voltage at About 3,3V and the Drain-Source at 0.
The boards are wired up like this: (sorry for the bad wiring diagramm, never worked by Fritzing or something like this)
I really suck at stuff like this especially when transistors or mosfets are involved, so any help is appreciated.
Thank you!
Best Answer
First, you need to give the LED it's own circuit, like this:
simulate this circuit – Schematic created using CircuitLab
The MOSFET you have chosen, though, will not work for this circuit; from the datasheet:
If you look closely, the threshold voltage (which may be as high as 4.9V) is specified at a drain current of \$255 \mu A \$.
To fully turn this device on, you need 10V \$ V_{gs} \$ drive so it is not really a logic level FET.
There are devices that will do what you need; in manufacturer parametric tables such devices have \$ R_{DS}{(ON)}\$ tabulated against various \$V_{gs}\$ drive levels.
Look for a device that has a 2.5V \$V_{gs}\$ drive capability.
Likely sources are Vishay and Diodes Inc to name but two.