Introduction to Switch Mode Power Supply (SMPS)

Indroduction to SMPS

What is SMPS? SMPS stands for switch mode power supply. The function of switch mode power supply is to transform the voltages from one level to another level. Typically it is taken from main AC and transformed into regulated DC voltages that required for electronics circuit.

Advantages of SMPS

Switch mode power supplies have gained very much popularity since in the beginning of 80’s
because of it’s benefits. the advantages of the SMPS are:

• Small size and lighter weight
• Gigh efficeincy and less heat generation
• Better regulation
• Wide range of AC input
• Low cost

Disadvantages of SMPS

SMPS have also some disadvantages in the comparison of linear
power supplies such as:

1)Because of more electronic components used in the power supply circuit and when failure
accurs. it could take out many parts in the SMPS
for example; lighning strikes on the Switch mode power supply

2) With so many different type of circuits used in the design of a Switch mode power supply such as
feedback, oscillator, protection, start up and etc and when problem happens it could actually
cause complication when it comes to troubleshooting and repairing the SMPS

3) Some spare parts are expensive and quite hard to get from the market for example:
power FETs, power ICs and switch mode transformer.

4) Strong electromagnetic interference (EMI) generated by the SMPS, without proper
shielding can cause the computer or other devices to generate intermittent problems.

5) Strong induced voltage(s) get feedback to the mains, thus polluting the
main supply to the other device in use nearby.

Where is SMPS used?

To reduced codt, size and wait, Monitors, TVs, Mobile charger, PCs, laptop and camcoder, printers, power packs, fax machines, portable CD players. DVD players, VCRs, microelectronics-based device in automotive, computing, communications, consumer electronics, and industrial application use SMPS.