LED Dimming problem!

[UroBoros]

I need to slowly DIM and slowly make a LED brighter. The LEDs are ceiling lights may be in the range of 6W-12W. it is having a SMPS already there.
So I plan to introduce a MOSFET between the SMPS and LED which in turn will PWM'ed from a Microcontroller. This is my plan and I tried it, but the dimming is not smooth especially in the extreme low brightness area.

is there any commercial modules which can be interfaced to a micro controller for dimming leds?

1. is there any specific LED dimming ICs which can be controlled from a micro controller via SPI or IIC?
2.if we are doing PWM to dim and led using Micro controller what should be the optimum pwm period to get a smooth effect?

even if i tried the lowest possible pwm duty cycle, the led cannot be made to off in a linear fashion. is it because of the nature of LED lights or problem with MOSFET switching?


Thanks

 

[ArNvC]

Hi,

is there any commercial modules which can be interfaced to a micro controller for dimming leds?

Yes of course, but might be a bit costly for your purpose,
I think you should go through this website, https://www.epanorama.net/documents/lights/lightdimmer.html

its really helpful...

Microcontroller based LED dimmer https://www.eetimes.com/document.asp?doc_id=1272415