Abstract
In this dissertation, a balanced buck converter was designed and implemented into a light emitting diode (LED) driver. Balancing a buck converter allows the mitigation of conducted common mode (CM) electromagnetic interference (EMI). This balanced converter is designed to implement in any device that requires a buck converter. Other methods to reduce EMI that were also investigated show similar results of reducing EMI in terms of the balancing method but to a lesser extent. The following factors were investigated to reduce the conducted CM EMI for a buck converter:
Layout inductance:
The reduction in layout inductance, results in the components in the circuit to be closer to each other, therefore making the physical size of the printed circuit board (PCB) smaller. Reducing the layout inductance reduces CM noise, due to the decrease in coupling capacitance and ringing.
Copper pour size:
Decreasing the size of the copper pours in the circuit reduces CM noise. This method has also shown to reduce differential mode (DM) noise but not to the same magnitude as CM noise.
Balancing circuit:
Balancing a circuit, in this case a buck converter circuit, in results the most significant reduction in EMI. The balancing method focuses on CM noise reduction because the operation of the balanced buck converter was kept the same as the unbalanced buck converter.
This study provides designers with an understanding of the importance of buck converter layout when needing to reduce EMI. It also demonstrates the trade-off between the reductions in EMI versus the physical circuit size of the buck converter.
M.Ing. (Electrical and Electronic Engineering)