What is the switching power supply in PC power supply?
Definition of PC power supply
The power supply used in personal PC is based on a technology called "switching mode", so we often refer to personal PC power supply as Switching Mode Power Supplies (SMPS for short), and it also has a nickname-DC-DC converter. In this article, we will explain the working mode and principle of switching power supply, the introduction of internal components of switching power supply and the functions of these components.
linear power supply
At present, there are mainly two types of power supply: linear power supply and switching power supply. The working principle of linear power supply is to first convert 127 V or 220 V commercial power into low-voltage power, such as 12V, and the converted low-voltage power is still AC. Then it is rectified and rectified by a series of diodes, and the low-voltage AC alternating current is converted into pulsating voltage (with "3" in Figures 1 and 2); The next step is to filter the pulsating voltage through the capacitor, and then convert the filtered low-voltage alternating current into DC direct current (with "4" in Figures 1 and 2); At this time, the obtained low-voltage DC is still not pure enough, and there will be some fluctuations (this voltage fluctuation is what we often say as ripple), so it needs a zener diode or a voltage rectifier circuit to correct it. Finally, we can get pure low-voltage DC DC output.
Although linear power supply is very suitable for supplying power to low-power devices, such as cordless phones, PlayStation/Wii/Xbox and other game consoles, for high-power devices, linear power supply will be inadequate.
For linear power supply, the internal capacitance and transformer are inversely proportional to the frequency of AC mains: that is to say, if the frequency of input mains is lower, the linear power supply needs larger capacitance and transformer, and vice versa. At present, AC mains power with the frequency of 60Hz (50Hz in some countries) has been used, which is a relatively low frequency, so its transformers and capacitors are often relatively large. In addition, the bigger the surge of AC mains, the bigger the transformer of linear power supply.
It can be seen that for the personal PC field, it will be a crazy move to manufacture a linear power supply, because its volume will be very large and its weight will be very heavy. Therefore, personal PC users are not suitable for sharing linear power supply.
