Power Electronics

A power supply is an electrical device that supplies electric power to an electrical load. The primary function of a power supply is to convert electric current from a source to the correct voltage, current, and frequency to power the load. As a result, power supplies are sometimes referred to as electric power converters.


The method of switch mode power supply is classified by circuit method of DC-DC converter. There are 2 methods for oscillator: self-oscillating converter where positive feedback from the power transformer to provide the oscillatory behavior, and separate-course oscillator with PWM control IC.

Self-oscillator changes operating frequency depending on input voltage and load, but separate-course oscillator does not change operating frequency.

Forward converter and flyback converter are methods of transfer of energy from primary to secondary source. The forward converter transfers energy when the switching transistor is ON (ON-ON converter), but flyback converter transfers the energy when transistor is OFF (ON-OFF converter).

1. forward converter

2. Push-pull converter

3. Half Bridge converter

4. Full bridge converter

5. Flyback converter

6. Buck regulator

7. Boost regulator

8. Buck-boost converter

A power switching circuit which uses a center tapped transformer and two power switches which are driven ON and OFF alternatively. This circuit does not provide regulation by itself.

A power switching circuit similar to the full bridge converter except that only two transistors are used, with the other two replaced by capacitors.

A power switching circuit in which four transistors are connected in a bridge configuration to drive a transformer primary.