# PWM signal with NMOS to adjust LED Driver

I have to design an LED driver for work. I am using the IS31LT3360 as the driver chip. On page 10 of its datasheet it states the chip can be driven with pwm. I came up with the following circuit. I would appriciate any feedback on wether I am doing this correctly. The mosfet is driven with a 0-3.3V PWM signal.

"The PWM signal must have the driving ability to drive internal 500kΩ pull-up resistor. "

What does that mean? I am not sure what driving a resistor means.

Datasheet IS31LT3360 :

Edit after Marcus's comment. The datasheet suggests using a MCUs output (AS LONG AS IT IS BELOW 5V AND ABOVE 1.2V, better?) as below to drive the chip.

• Ok, I feel like I should write the following: couple of days ago, you were in the middle of design for your bachelor thesis, now you're deigning a LED driver for work. Especially if you're doing your bachelor thesis within a company (as opposed to at a university institute), make triple sure that you get enough time to finish your thesis. Talk to your boss about that. Calculate how many hours working on your bachelor's is supposed to take, and make 100% sure you get that time, and the company is on-board with that. I've seen industry bachelor theses fail due to the student working too much. Jan 13, 2021 at 17:05
• @MarcusMüller I am working for an Institute. My bach. thesis is interconnected. This LED driver will go into the same system as my bach. thesis. Boss wants the machine to look prettier Jan 13, 2021 at 17:10
• You are working on your bachelor thesis? Please break your question down...tell us exactly which part of the sentence you don't understand. Do you know what "pull-up" is? Jan 13, 2021 at 17:17
• @ElliotAlderson I know what a pull up is. I am not sure what driving a resistor means thoguh. Jan 13, 2021 at 17:18
• @EmreMUTLU no, it doesn't. The next sentence says the high-going threshold is 1.2 V. So, your 3.3 V is totally sufficient. ("many other designs" doesn't matter – what matters is your design in your application, and my guess is that if your B.Sc. is about circuit design, then that's twice as true!) Instead, the datasheet actually suggests directly driving the ADJ pin from a microcontroller pin with naught but a series resistor (and a protection diode). Jan 13, 2021 at 17:33