SMPS

What is SMPS?

• Stands for Switch Mode Power Supply.
• Supplies power to all the parts of the computer.
• Converts 230V AC to 3.3V, 5V, 12V DC.

What are the main functions of SMPS?

• Inverting and producing multiple dc output voltage required for different parts.
• Protection from short circuit and overload.
• Produce regulated dc output.

How does SMPS work?

Input Rectifier and Filter:

Converts AC to DC. The rectifier produces unregulated voltage which is sent to filter to produce regulated DC voltage.

Chopper:

The fixed DC is converted to a variable DC. 

Transformer:

The transformer steps down the voltage from the chopper.

Output Rectifier and Filter:

Produces a constant DC output voltage.

Feedback circuit:

The output sensor of the feedback circuit senses the output voltage and compares it with the reference voltage and produces error voltage which is used to control the chopping frequency to get the desired output.

Parts and Connectors of the SMPS:

Power In:
Power cable is connected here which is the input of mains supply.
Fan:
To reduce the heat generated by the SMPS.
Connectors:
All the connectors provide DC supply to different parts of the computer.

Advantages:

• Lighter and small size.
• Low noise.
• High power efficiency.

Disadvantages:

• Complex circuit design.
• Expensive compared to linear supplies.