Introduction to the difference between switching power supply and linear power supply
1, Regarding the Development of Power Supply Technology
The development direction of modern power electronics technology is shifting from traditional power electronics, which mainly deals with low-frequency technology, to modern power electronics, which mainly deals with high-frequency technology. In the application of power electronics technology and various power systems, switch mode power supply technology is at the core.
From the self oscillating push-pull transistor single transformer DC converter invented by G. Roger in 1955, which was the beginning of realizing high-frequency conversion control circuits, to today's switching power supply technology becoming an indispensable power source in the rapid development of the electronic information industry.
What is a switching power supply
Switching power supply is the abbreviation for switching voltage regulator power supply, generally referring to an AC (alternating current) - DC (direct current) converter that inputs AC voltage and outputs DC voltage. The power switch tube inside the switching power supply operates in a high-frequency switching state, consuming very low energy. The power efficiency can reach 75% to 90%, which is twice as high as that of ordinary linear stabilized power supplies.
1. Working principle of switch mode power supply
Switching power supply is a type of power supply that utilizes modern power technology to control the time ratio of switching transistors on and off, maintaining a stable output voltage. The switching power supply is composed of pulse width modulation (PWM) control (metal oxide semiconductor field-effect transistors).
Switching power supply consists of four main parts: main circuit, control circuit, detection circuit, and auxiliary circuit. Switching power supply, as the name suggests, is equivalent to having a door here, one door allowing current to pass through and the other door stopping current from passing through. So what is a door?
Some switching power supplies use thyristors, while others use switching transistors, which rely on the base and control electrode (thyristor) plus pulse signals to complete conduction and cutoff, allowing the electronic switch to continuously 'turn on' and 'turn off', and enabling the electronic switch device to pulse modulate the input voltage, thereby achieving DC/AC, DC/DC voltage conversion, as well as adjustable and automatic voltage regulation of the output voltage.
The difference between switch mode power supply and linear power supply
Simply put, the voltage regulation of a linear power supply can be seen as a resistance value regulation, which is equivalent to changing the voltage by adjusting the sliding resistor, while a switching power supply changes the voltage by adjusting the frequency of the switch. Meanwhile, compared with linear power supplies, the cost of both switching power supplies increases with the increase of output power, but the growth rates of the two are different.
1. The cost of a linear power supply is actually higher than that of a switching power supply at a certain output power point.
Therefore, with the development and innovation of power electronics technology, switch mode power supply technology continues to break through and innovate. This cost issue has instead shifted switch mode power supply technology towards the low output power end, providing a wide range of development space for switch mode power supply.
