Backlight dimmer problems

[kurt-olsson]

My first try was to use mosfets to control my 5V backlight.

Almost All mosfets are from 5V and higher voltages. I need 0-5V but cant find any. Also, these units run really hot even with heatsink. And also there is a sagnific voltage drop (~8V gives 5V with D4184 Mosfet).

I can use 12V hardware dimmer i guess but the dimming level will be bad. Almost all dimming the first 5% of knob position and 100% the rest.

I allready have lots of 5V PSU for backlight and if using real aircraft dimmer i need 28V units.


Any tip here? i am stuck! Haha

[ame]

Please post your schematic, and explain how everything is connected. And please state clearly what you are trying to achieve.

I am using a cheap Chinese MOSFET module to dim an LED lighting strip at home. It is 24Vdc at around 30W. The MOSFET is driven by a 3.3V PWM signal. The module barely gets warm.

[kurt-olsson]

Sorry again for not posting schematic. Its impossible to help without it.

Murphys law!

Either i shortened the first one or bad from the factory.

I tried another one and it worked great!!!

No voltage drop worth mentioning and i pull about 7Amps without heatsink.

I can highly recommend the D4184 right now on initial testing.