A boost converter (step-up converter) is a DC-to-DC power converter with an output voltage greater than its input voltage. It is a class of switched-mode power supply (SMPS) containing at least two semiconductors (a diode and a transistor) and at least one energy storage element, a capacitor, inductor, or the two in combination. Filters made of capacitors (sometimes in combination with inductors) are normally added to the output of the converter to reduce output voltage ripple. AC-DC converter with high frequency transformer is most widely used in switched mode power supply (SMPS), battery charging, uninterrupted power supply (UPS), electronic ballast, induction heater. SMPS works like a DC chopper by operating the on/off switch rapidly, AC ripple frequency rises which can be easily filtered by L and C filter circuits which are small in size and less in weight. It may therefore be inferred that is the requirement of small physical size and weight that has led to the wide spread use of SMPSs. If the switching devices are power transistor, the chopping frequency limited to 40 kHz. For power MOSFETs the chopping frequency is of the order of 200 kHz as a result size of the filter circuit and transformer decreases leading to considerable savings. as such high frequency, ferrite core is used in transformers. The overall size of SMPS it depend on operating frequency.