Transistor / mosfet for PWM dimming of 30W RGB LED

controllerledmosfetpwmtransistors

I am building a led mood light with a high power RGB LED (30W) using 3 constant power supplies for each color.

These are the items I had in mind (but open to suggestions):

30W Integrated RGB LED Light Bulb (10 Series and 3 in Parallel)
JR-30W 30W Waterproof LED Power Driver (AC 85~265V)

Each color will be controlled with PWM by arduino. So far so good, the problem is that the bc337 transistors I have can only go up to 800ma so I need something significantly beefier. What is my best and simplest option here? I'm not very knowledgeable in electronics so simplest solution would be best.

Best Answer

Well, the specifications of the device you linked are grossly inadequate.... but given you have 10 LEDs in series, I expect you'll operate at something like 40VDC...

Arduino analogWrite function generates PWM at about 490Hz.

I would suggest setting up a high side switch with a P-channel MOSFET (e.g. IRF9Z24) conrolled by an NPN BJT (e.g. 2N3904). Say 100ohm resistor into the base of the BJT and a 4.7kohm pullup on the gate of the MOSFET. Connect LED between MOSFET drain and GND. Connect PWM input to the aforementioned 100 ohm resistor.

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