Soft starting a 100W led can it be done with a 555 and pwm?

[Hagis2k]

Hi fellas been sitting here thinking a bit on how to get an 100W led to soft start the most easy way
i been trying to figure out if a simple 555 timer and a mosfet can do it as there is many circuits online
on 555 pwm is there any way to make the duty cycle to increase on power on from like 0-100% in 3-4sec?


Will probably take the breadboard and start playing around a bit i know
i can do it with aurdino but i rather stay with non microprocessor things for this

[Marco]

The easiest is to buy a 100 Watt LED driver with dimmer and mod the dimming input.

[SArepairman]

you need two triangle wave generators and a comparator.

One triangle wave goes to one input of your comparator (at the frequency of you PWM), the other triangle wave is the duty cycle (I imagine this could also be done with just a RC circuit, it does not need to be perfectly linear right?), the comparator will produce a square wave with a duty cycle that steadily goes up.

[NiHaoMike]

Easiest way is to use a current mode PWM controller and a RC time delay to ramp up the current setpoint.