Creating a simple voltage regulator for medium currents

Question, as fast as possible: Would this circuit regulate poorly-regulated +12VDC effectively?

I am an electronics level zero, so please bear with me. Please let me know if you would me to clarify anything.

Full Question:

I'm trying to design this smart lighting system and I need a power source. Unfortunately, due to the wire run lengths, I can not rely on receiving well-regulated +3.3v directly, especially at high currents.

I want to keep the device as small and low-profile as possible, limiting my options.

I designed this circuit to regulate voltage effectively. Would this work?

I am alright with up to 0.2v of ripple. All resisters are 1k ohms, and the capacitor is 100uF.

Also, if I messed up something which would make this circuit blow up, please let me know. This one of the first circuits I've designed from scratch.

• How much current do you need from it? Commented Jun 23, 2016 at 1:06
• About 1-3 amps at most. Commented Jun 23, 2016 at 1:07
• 3A is not going to be a small circuit with a linear regulator. Grab a switching regulator off eBay. Commented Jun 23, 2016 at 1:08
• How is this a linear regulator? Doesn't the MOSFET switch on when the voltage is low, and off when high? Commented Jun 23, 2016 at 1:09
• You don't have an inductor, and you don't have hysteresis. Performance will be in the toilet. And that's if you're lucky. Commented Jun 23, 2016 at 1:10

I can do a little bit math for you. If you have Vin = 12VDC, Vout = 3.3VDC and draws I = 3A at 3.3V, then you will have (12 - 3.3) * 3 or 26.1W wasted power with a linear regulator. You will get totaly 9.9W, so with other words a efficiency of 37%.
Since you only need 3A, then you set the Rsense to 0.01 Ohm, and to get 3.3VDC out of it, you need to change Rselect to 1.66K.