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SMPS Transformer

Little Known Ways to SMPS transformer function

What are switch power supply transformers?

First, what are switch power supply (SMPS) transformers? An SMPS transformer is an electronic power supply that integrates a switching regulator to convert electrical power efficiently. It steps up or steps down both voltage and current and provides isolation between the input and output sides. It converts a DC source to either AC or more output DC sources. The incorporated switching regulator helps in controlling the amount of power delivered to the transformers load circuit by changing the output voltage and current by switching lossless storage elements like inductors and capacitors. Such elements ideally have no resistance when “on” and do not carry current when in “off” condition hence offer profound efficiency.

smps transformers topologies

There are numerous topologies available as listed below

  • Boost
  • Buck and boost
  • Fly back
  • Forward isolated buck step down
  • Push-Pull converter with two primary windings
  • Half Bridge
  • Full bridge

Basic components of SMPS transformers

  • Input rectifier and filter
  • Inverter consisting of a high-frequency signal and switching devices
  • Power transformer
  • Output rectifier
  • Feedback system and circuit control

How are SMPS transformers different from the other transformer?

Just like power transformers, SMPS are AC devices. They cannot operate from a DC source. SMPS transformer but the can sustain transformer operation in a transient condition which allows for resetting of magnetic flux. SMPS have switching regulators that repeatedly switched to allow for the magnetic field to reverse thus reversing the polarity of the transformer.

In which applications are SMPS transformer used?

Switch mode transformers are used very in electronic applications mostly within power supplies to convert power from a DC source to either AC or more output DC sources. They are usually referred to as DC to DC converters. They convert conventional low-frequency A.C to the required voltage, current and waveform thus are used in power supplies of many electronic devices.


Advantages of SMPS transformer

  • They are flexible
  • They have a high efficiency of between 68% and 90%
  • High power density
  • Offer stable outputs independent of the input supply
  • SMPS designs are compact hence use smaller transformers which save on space.

Disadvantages of SMPS

  • They are complex in design
  • Relatively costly since they have extra components
  • They generate EMI and electrical noise