{"id":4741,"date":"2020-11-15T18:50:55","date_gmt":"2020-11-15T16:50:55","guid":{"rendered":"https:\/\/dcaclab.com\/blog\/?p=4741"},"modified":"2020-11-15T18:58:35","modified_gmt":"2020-11-15T16:58:35","slug":"switch-mode-power-supply-explained-in-detail","status":"publish","type":"post","link":"https:\/\/dcaclab.com\/blog\/switch-mode-power-supply-explained-in-detail\/","title":{"rendered":"Switch Mode Power Supply Explained in Detail"},"content":{"rendered":"\n

A switch mode power supply, generally known as SMPS is an electronic device that is used to convert electrical power efficiently. This SMPS is more complex than conventional linear power supplies. The complexity increases but it give many advantages over the linear power supply.<\/span><\/p>\n

Why do we need a Linear Power Supply?<\/span><\/h2>\n

Well, this question must be clear before proceeding. All the electronic appliances (load) have different voltage and current ratings so we need to supply the electric power accordingly. This brings up the need for voltage regulators. They convert the mains supply voltage to the desired voltage of the particular electronic device.\u00a0<\/span><\/p>\n

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Linear Power Supply<\/p><\/div>\n

For this purpose, the Linear Voltage Regulator like the 78xx family is used most commonly as they are easy and simple to use. Let us understand with an example. Assume we have an electronic device that has a rated voltage rating of 5 volts. The ac mains supply has 230 volts which of course cannot be given directly to the device. Therefore, the mains supply is first fed to the linear voltage regulator (or maybe to an SMPS). Say an IC7805 is used as an LVR which converts the 230 volts to the 5 volts and then fed to the device.<\/span><\/p>\n

Now, there are certain issues with these LVRs such as heating issues and efficiency. This makes the need for the switched-mode power supply. Let us have a look over the advantages and the disadvantages of the Linear Power Supply.<\/span><\/p>\n

Advantages of LPS<\/span><\/h3>\n
    \n
  1. It is a simple and reliable system<\/span><\/li>\n
  2. Less ripple in the output voltage<\/span><\/li>\n
  3. Continuous power supply\u00a0<\/span><\/li>\n
  4. This circuitry responds dynamically to load changes<\/span><\/li>\n
  5. Noise is low, as it is linear<\/span><\/li>\n
  6. Circuit resistance changes to regulate different the different output voltage<\/span><\/li>\n<\/ol>\n

    Disadvantages of LPS<\/span><\/h3>\n
      \n
    1. More heat dissipation<\/span><\/li>\n
    2. The transformers used are large and heavier<\/span><\/li>\n
    3. Efficiency is less, around 40-50%<\/span><\/li>\n
    4. Only a single voltage is obtained at the output<\/span><\/li>\n<\/ol>\n

      Therefore, all the devices which do not have the efficiency constraints and a simple regulation work there LPS fits well. Thus, to overcome the disadvantages of the linear power supply, the switched-mode power supply is introduced.<\/span><\/p>\n

      Switch Mode Power Supply<\/span><\/h2>\n

      The drawbacks like the lower efficiency, the need for filters (large capacitance) to cut the ripples, transformer, etc, are overcome by the use of switched-mode power supply.<\/span><\/p>\n

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      Switch Mode Power Supply<\/p><\/div>\n

      SMPS has become the most common and almost has replaced all the conventional ac-dc power supply everywhere. This is because SMPS is able to cut down on power consumption, size, and weight and less heat dissipation. Most electronic appliances that demand high efficiency incorporate the switched-mode power supply.<\/span><\/p>\n

      Types of Switch Mode Power Supply<\/span><\/h2>\n

      SMPS is classified on the basis of input and output voltages. The main classification is as follows:<\/span><\/p>\n