Ishan Mukherjee

In this paper input filters of DC/DC converters used in consumer and industrial electronics are studied and analyzed with an intention of developing a low-noise design. Noise attenuation is carried out by developing noise models for thermal noise in single section input filters of Buck, Boost and Buck-Boost DC/DC converters. The models are applied to a basic buck converter example and simulated to propose attenuation techniques.

The cleaning process in the surface mount assembly line of power modules had been found to insufficiently remove solder flux residue from printed circuit board (PCB) assemblies after the process of reflow soldering. This thesis details the development of an optimized cleaning process that effectively removes solder flux residue from PCB assemblies. The first stage of this study involves the experimental validation of root cause of process ineffectiveness. A novel visual inspection based grading scale is developed to quantify the amount of residue present. Using the grading scale optimal process parameters were identified and studied. The study finds that power modules are most effectively cleaned in a saponifier based cleaning solution using ultrasonic agitation. Power modules are completely cleaned when washed in an ultrasonic bath at 60°C for 7 minutes, in a saponifier based cleaning solution that is 5% concentration by volume.

Input filters of DC/DC converters used in consumer and industrial electronics are studied and analyzed with an intention of developing a low-noise design. Noise attenuation is targeted by developing lumped-circuit-based noise model for EMI in input filters of Buck, Boost and Buck-Boost DC/DC converters. The models are applied to a basic buck converter and simulated to validate the attenuation techniques.