A Glimpse to Switching Power Supply

Modern electrical and electronics is developed from the traditional electrical and electronics which based on low frequency to modern electrical and electronics which based on high frequency. Switching power supply technology lies a core status in the electrical and electronics application and various power system.

Since 1955, GH Roger from US invented self-oscillation push-pull transistor single transformer DC converter, which realized the begin of high frequency switching control circuit， till now, switching power supply technology has became essential power source of electronic information industry.

Why did switching power supply technology become the most core status of modern electrical and electronics technology? Only depend on its miniaturization and easy installation with electrical equipment?

What is a switching power supply?

An abbreviation of stabilized switching power supply, switching power supply generally refers to a AC to DC converter with input AC voltage and output DC voltage. Internal power switch tube operates under high-frequency switch status, consumes low energy, and efficiency can be 75%～90%，better than linear power supply.

So, what’s the difference lies between switching power supply and linear power supply?

Simply speaking, voltage regulation of linear power supply can be regarded as regulating value of resistance, change voltage by regulating slide rheostat; while for switching power supply, to change voltage by regulating switch frequency. Meanwhile, cost increased by the increasing output power of switching power supply and linear power supply, just different rate of rise.

At a certain output power, cost of linear power supply is higher than switching power supply.

Therefore, by the development and innovation of electrical and electronics technology, switching power supply technology continuous break through and innovate, the cost problem causes switching power supply technology moving to low output power end, thus provide widen development space for switching power supply.

Working principle of switching power supply

By using modern electrical and electronics technology, switching power supply controls open and close time ratio of switching transistor, compose of PWM control and half-time transistor can maintain stable output voltage.

Switching power supply is consist of pilot circuit, control circuit, detect circuit and auxiliary circuit, just as its name implies, there are two doors, which one current pass, and other one make it stop.

Advantage of switching power supply

Eelectrical and electronics equipments relate closely to human work and life day by day, and the equipments cannot do without stable power supply. Switching power supply uses widely in computer in 1980s, and uses in various electrical and electronics.

Switching power supply technology rapidly plays core role for electrical and electronics equipment no later 10 years, is it only owing to its compact size?

In fact, we can see from its schematic diagram, switching power supply has no bulky industrial frequency transformer, meanwhile, leave out bigger heat sink owing to power dissipation sharply reduce of compensating tube. This makes it smaller size and light weight. However, the most remarkable advantage of switching power supply is its low power dissipation and high efficiency.

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