Switched mode power supply (SMPS) is an electronic power supply that incorporates a switching regulator to convert electrical power efficiently, by transferring power from a DC or AC source to DC loads. The pass transistor of an SMPS continually switches between low dissipation, full on, and full off states, spending very little time in the high dissipation transitions, which minimizes wasted energy. Also, by varying the ratio of on to off time, voltage regulation is achieved. This high power conversion efficiency with no energy wastage is an important advantage of an SMPS.
Unlike linear power supply transformers, SMPS are small and light due to the smaller size and weight of the transformers installed, which is why they are effectively used as replacements for linear regulators when high efficiency is required with lighter weight and smaller size. The transformers that are mainly composed of magnetic core and winding, are used for conversion, energy storage, and isolation. But, the materials used will affect the performance of the transformer, which will in turn affect the heat dissipation and working efficiency of the equipment. Thus, you need to be very sure about the materials that you are having installed in your SMPS transformer. This is why when planning on getting an SMPS transformer for your application, you need to approach only an expert transformer manufacturer in India, one like Miracle Electronics, who has immense knowledge about, and enough experience of manufacturing and working with SMPS transformers.
Advantages and disadvantages of using SMPS transformers
- One of the main advantages of using SMPS transformers is that you can have efficiency up to 96% because the switching transistor dissipates very little power when acting like a switch. Other advantages include small size, light weight, and low noise. Also, the standby power loss is very low.
- One disadvantage is that they are very complicated and they can cause electrical noise problems if not carefully suppressed; thus causing harmonic distortion.
SMPS transformers are divided into two types – unipolar and bipolar. Unipolar transformers are characterized by a unipolar pulse as input voltage, and are divided into positive flyback voltage output. Bipolar transformers are characterized by a bipolar pulse as input voltage, with the output generally being bipolar pulse voltage.
Materials used
As mentioned above, it is very important to choose the right materials for the SMPS transformer. There are three main components of an SMPS transformer – magnetic materials, wire materials, and bobbin materials.
Magnetic materials – These are soft ferrite which are divided into two categories according to their composition and application frequenct – MnZm and NiZn.
Wire materials – Polyurethane and polyester enameled wires are generally used to wind small electronic transformers, divided into thin paint and thick paint types, depending upon the thickness of the paint layer.
Bobbin materials – Bobbins of SMPS transformers are different from general transformers, as they play a dual role of mounting and positioning of the entire transformer, along with insulating and supporting the coil. Thus, the bobbin material needs to meet insulation requirements, as well as possess tensile strength and heat resistance.
