Life is GUI: Part 2-b: Developing Power Conditioning / Buzzer Circuit

Hell0 Everyone, what a crazy week it was! I apologize for the lack of updates, but I was swamped last week. I had to wake up with my wife at about 6:00 AM every morning, and didn't get to bed till about 12:00 AM. That's what happens when class work clashes and in one week there are: 2 tests (one got moved to today :) ) , 2 labs, multiple homework's, a Design Specification presentation, and trying to make some progress on SP. With that said, let me catch you up with my design of the power conditioning circuit and start buzzer control. I know all of you have read my Design Spec and are just dying to find out what my implementation of these circuits look like ;) .

To summarize my Design Spec, the FPGA development board needs about 7.5 volts at roughly 600 mA in order to function. The tricky part comes from the piezo buzzer that I have selected, which needs 12 volts and must be controlled by only a 3.3 volt signal. In steps two very helpful devices: (1) a power regulator that will convert 12 volts to 8 volts (LM7808), and (2) a MOSFET (IRLZ34N), the same used in the gunshot detection circuit. Below are the block diagrams of these 2 devices being used (the power regulator is within the "Power Conditioning" block):

You may have noticed that the regulator outputs 8 volts, and the block diagram shows 7.5 volts. In reality, the regulator is not perfect and only outputs about 7.8 volts (with the power LED connected and now load being connected). As it turns out, there is enough conditioning on the the FPGA board that it can comfortably handle 7.8 volts.

Here are the schematics I developed for these 2 circuits:
TOP: Buzzer Circuit
BOTTOM: Power Conditioning Circuit