PCB for Power source circuits
The power source circuits that supply the IR LED ring and micro-controller utilize the LM2679 switching regulator. The regulator will step down the input voltage, usually an external battery, into the desired output voltage and current depending on the components that are connected to it. The schematic of the power sources designed can be seen below:
As seen the in the figures of the power source circuit, the circuit is comprised of components such as resistors, capacitors, and other components. The input capacitor is used to help smooth out input variations. The resistor is used to adjust the current limit and control the peak switch current. The output capacitor helps smooth out the dc output voltage as well as provide energy storage. The inductor stores energy when the circuit is on and sends the stored energy back to the load when it is off. The boost capacitor improves the efficiency of the regulator. The diode allows current to flow through it when the regulator is off and when current is flowing from the inductor. Further specifications on what kind of components can be connected with the switching regulator can be found in the datasheet of the LM2679 switching regulator.
For this project, the required output voltage and currents are 5V, 4A for the Odroid microcontroller and 12V, 1A for the IR LED ring. A 5V, 4A output is required for the microcontroller because it is the amount of supply needed to power the Odroid microcontroller. The 12V, 1A output is required for the IR LED ring because the IR LED ring schematic is designed in such a way that it needs a 1A in order to light all the IR LEDs evenly at the desired intensity
The next step will be to implement the designed circuits onto a PCB using a software called KiCaD. An example of the PCB for the power sources used for this project is shown below:
The PCB shown is just a simple example of how the circuit can be configured onto the board. It is up to the user to configure a PCB with their own sense of organization. With this aside, the PCB should function similarly to the power circuits, and then be applied to their objectives, which are the micro-controller and IR LED ring.
PCB files used for this project can be found in the following link:
For help in designing the PCB on KiCaD, the following tutorial can be useful: