CE351  Fall  2020
Power Supply and DC Regulator PCB for MCUs
Name: Cheyenne Tucson
Email: crtucson@fortlewis.edu

                                                               Home Work 1 - Power Supply and DC Regulator Printed Circuit Board
1. Introduction
    Learning how to design printed circuit boards (PCBs) is a great skill to have as a computer enigneer. For this lab, we designed a PCB of a AC/DC converter jack with DC voltage regulators to provide 5V and 3.3V outputs
    with options for both 1A and 3A current outputs. This PCB will later be used as a power supply circuit for our MCUs and the projects to follow.

2. Materials

3. Procedure
    For this lab, we created our 1A circuit by following the schematic of a common DC-DC voltage converting circuit. The circuit we used for reference is shown below:

    For our purposes, the left and right power rails and the power tap headers were left off so that we could later add our own that fits our purposes better.

    For the 3A circuits, we followed the schematics, provided by Texas Instruments, of circuits commonly used with the LM2596 voltage regulators they make. We followed one for a 5V 3A output with an input range of 7-40V.
    We also followed one for 3.3V 3A output with the same input range.
    Finally, we added 3 male header-pin pairs for shorting the different input options, and 4 pairs of female header pins, one pair for each output option. Once this was done, we designed the necessary libraries for the components we are using.
    Libraries were created only if they were not already found in the SparkFun Eagle libraries. After the schematics were drawn in Eagle, we began to format the physical layout of the PCB itself.
    The schematic with just the 1A circuit:

    The schematic with both 5V/3V 3A circuits, the 5V/3.3V 1A circuit, and the headers.

    The PCB layout of both the 1A and 3A circuits

    Checking for errors with the DRC and ERC:

    The libraries and project files can be found here.

4. Results
    The finished product of the PCB design with all components soldered.

The PCB was then probed with a multimeter to measure the voltage output at various places around the board.
The results of probing the 1A circuit is shown below. The 3.3V output pin is shown on the left, and the 5V output pin is shown on the right.

The results of probing the 3A circuits are shown below.

As demonstrated above, the functionality of the finished PCB is as planned. This PCB design was successful. Revising the physical layout for efficient spacing will be practiced in future PCB designs.