PBL sem 1 - PWMckt

This project is about efficiently controlling the power that is delivered to a load by means of modulating the power supplied to it.
One way of regulating the voltage (and hence the power) is by using a linear regulator. A linear regulator is put between the power supply (like a battery) and the load in order to regulate the voltage appearing across the load. This can be achieved with the help of linear regulators, such as the LM78XX series of ICs, which are very straight forward, compact, economical and easy to use. However, these regulators work by behaving as a variable resistance placed in series to the load, dropping the excess voltage and converting the excess electrical energy into heat. This form of voltage regulation generates a lot of heat, especially at a high current draw. Due to this, a heat sink may be needed to help dissipate the heat fast enough in order to prevent the regulator IC from overheating. This is a very inefficient method of voltage regulation.
The other way of regulating the voltage efficiently is by modulating the power going to the load. This is achieved by turning the power to the load on and of very quickly, thus limiting the power. In this method, the “excess power” is not dissipated in the form of heat, but it is not “used at all”. Pulse Width Modulation (PWM) is a very efficient way to regulate voltage and is used everywhere. Using PWM, one can build a Boost Converter to efficient step-up DC voltages, or a Buck Converter to step-down DC voltages.
This circuit uses Pulse Width Modulation to effectively reduce DC voltages.

Please check the project report (in attachments) for full details.