College of Engineering
Electrical Engineering Department
BS in Electrical Engineering
This senior project aims to provide design and test the performance of a DC-DC constant current LED driver for use in a larger DC smart building infrastructure. In this instance, a SEPIC topology is chosen to provide high efficiency output current at output voltages that can be above or below the input voltage. This is challenging since the same design must operate at similar efficiency for vastly different environmental conditions. As a part of a larger system, the design must be able to perform the given task consistently regardless of changes to the source and load power.
The design uses the LT3795 LED controller to operate power switches and inductors to transform the input power into usable output power for a string of LEDs. The controller is paired with an onboard microcontroller to provide error reporting and supplement the PWM dimming control features of the IC. Simulations were done to ensure the efficiency of the design remained above 93% within the full range of input and output voltages, along with a range of PWM frequencies and duty cycles.
After manufacturing and assembly, the board was found to be under specification regarding the input and output voltage ranges, as well as below the efficiency target. This was largely due to issues regarding the layout assembly of the finished product.