Latest mobile chargers are kind of power supply units that use the Switched Mode Power Supply (SMPS) technology. To understand the working phenomenon of a mobile charger, we need to understand the concept of Power Supply Unit (PSU). PSU is a device that transfers electrical energy from one end to another by changing its fundamental characteristics according to the requirements. Example of a PSU is an application that converts AC mains voltage to regulated DC voltage. PSUs can be of two types depending on the mode of operation – Linier and Switching. In these switching mode chargers, energy transfer is done by continuously switching electrical components (inductor, capacitor, etc) on and off. We can control the output voltage/current by varying the duty cycle, frequency or the corresponding phase.