The most important element of an electronic circuit is the power supply that provides current to the entire circuit. Different circuits require different kinds of power of different ranges. This is why different power converters are used to change the power into the range that is required by the individual application it is applied to. This is where the Switch Mode Power Supply (SMPS) comes in handy, which is an electronic circuit that converts power using switching devices and inductors or capacitors to change the electrical power from one form to another as required. The power supply is generally used to achieve regulated DC output voltage from DC input voltage or unregulated AC.
How does SMPS work?
SMPS consists of a switching regulator that manages the regulation in the unit. This switching element switches the current supply to a smoothing capacitor on and off. The voltage on the capacitor controls the time that the series element is switched. It is the continuous switching of the capacitor that maintains its voltage at the required level. The AC power first passes through the fuses and a line filter, which is then rectified by a full-wave bridge rectifier. This rectified voltage is then applied to the power factor correction pre-regulator, which is then followed by a DC-DC convertor.
What are the different types of SMPS available?
DC-DC Converter – In a DC-DC converter, the power that is received from the AC main is rectified and filtered as high voltage DC, which is then switched at a huge rate of speed and fed into the primary of the step-down transformer. The filtered and rectified output is then received at the secondary of the transformer, which is further sent to the output of the power supply. Some of this output is sent back to the switch to control output voltage.
Forward Converter – In a forward converter, the diode carries the current during the ‘Off’ stage of the transistor. This is why energy flows into the load in the ‘On’ stage as well as off stage too; and this current is carried by the choke. It stores energy during the ‘On’ stage and also transfers some of it into the output load.
Flyback Converter – In a flyback converter, the magnetic field of the inductor stores energy during the ‘On’ period of the switch, which is then emptied into the output voltage circuit when the switch is open. This duty cycle decides upon the output voltage of the circuit.
Self-oscillating Flyback Converter – This is the simplest and most basic converter wherein the current that flows through the transformer primary starts rising continuously with the slope during the conduction time of the switching transistor. And, when this current reaches its peak, the core begins to saturate.
What are the pros and cons of SMPS?
As compared to linear regulators, the SMPS is much more efficient with lesser standby power loss and smaller size with light weight, along with being much more cost-effective. However, the SMPS is more complex than linear regulators, and it generates higher amplitude, frequency, harmonic frequency, and ripple voltage. Also, it pairs electrical switching noise back onto the main power line, thus causing interference with equipment connected to the similar phase.
For getting your hands on the best quality SMPS to be used in machine tool productions, security systems, AV products, support supplies for PLCs, or any other relevant application, you can approach Miracle Electronics, the leading SMPS transformer manufacturer in India. You can get high power-to-size ratio SMPS transformers that are RoHS compliant and high reach compliant to achieve minimal power wastage.