I am studying a commercial product of LED DIMMER controlled based on PWM.

The product can dim the LED with the following specifications.

Maximum Spec : 12VDC, 50A, 600W

And as the core device, SM6020NS Mosfet is used. (http://www.sinopowersemi.com/temp/SM6020NSFP_datasheet.pdf)

I have a question here.

**Q1. The device can dissipate up to 83W of power at a case temperature of 25 degrees,**

But, The device's Rds(on) is 4.5m Ohm.

And, Mosfet power consumption formula I think is as below.

But, The device's Rds(on) is 4.5m Ohm.

And, Mosfet power consumption formula I think is as below.

`I = 50A`

R = 0.0045 Ohm

W = V * I

V = I * R

V = 0.225V

W = 11.25W

**Why does the manufacturer of the product not use a product that can only consume 20W, but use a device that can consume 83W?**

Q2. How can you help me with Thermal Resistance-Junction to Case or Thermal Resistance-Junction to Case?

Q3. The picture below is a commercial product that I am currently studying.

I would like to make a product like this myself.

Can you give me a link to find a starting point for me to study?

Q2. How can you help me with Thermal Resistance-Junction to Case or Thermal Resistance-Junction to Case?

Q3. The picture below is a commercial product that I am currently studying.

I would like to make a product like this myself.

Can you give me a link to find a starting point for me to study?