SMPS is the Switched Mode Power Supply circuit which is designed for obtaining the regulated DC output voltage from an unregulated DC or AC voltage. There are four main types of SMPS such as
- DC-DC Converter
- Forward Converter
- Flyback Converter
- Self-oscillating Flyback Converter
1 DC-DC Converter
The power received from the AC power source is rectified and filtered to become high-voltage direct current. Then switch this high DC voltage and feed it to the step-down transformer on the primary side. On the secondary side of the step-down transformer, the rectified and filtered output is collected and finally sent to the power supply as an output.
2 Forward Converter
Regardless of whether the transistor is on or not, the choke will carry current in the forward converter. The diode inside the transistor carries current during the off period to support the energy flowing through the load. During the turn-on, the choke stores energy and transfers part of the energy to the output load.
3 Flyback Converter
In a flyback converter, the switching magnetic field of the inductor stores energy during on-time. When the switch is off, the energy is drained into the output voltage circuit. The duty cycle in the flyback converter is determined by the output voltage.
4 Self-oscillating Flyback Converter
It is based on the principle of flyback. During the turn-on period, the current flowing through the transformer primary begins to increase linearly with a slope Vin / Lp. Because voltage is induced in the feedback winding and the secondary winding, the fast recovery rectifier starts to work under reverse bias and keeps the conductive transistor on. Once the current reaches its peak, the core will begin to saturate. The result is that the fixed base drive supported by the feedback winding does not support a sharp rise in current. Therefore, the switch begins to leave the saturation state.