Linear DC power is better He is the output of a linear DC, can be used in demanding occasions, followed by switching DC power supply, he is a high switching speed of the transformer and the switch, characterized by small weight, high output quality , The phase control of the original used in the less demanding, the current is particularly large linear power supply, switching power supply to distinguish between the linear power supply adjustment work in the enlarged state, which heat, low efficiency (35%), need to add bulky heat Film, but also need the same large-volume power frequency transformers, transformers will be more bulky when making multiple sets of voltage outputs.

Linear power and switching power supply work difference

Linear power devices work in a linear state, which means that he used the power device is always working, so it also led to his work efficiency is low, usually 50% to 60%, have to say that he is very good linear power supply. Linear power supply work, so that he from high pressure to low pressure must have a pressure device, the general are transformers, there are other like KX power supply, and then rectified output DC voltage. As a result, his size is also large, bulky, inefficient, heat is also large. He also has his advantages: small ripple, good regulation, small external interference. Suitable for use with analog circuits, various types of amplifiers.

Switching power supply His power devices work in the switch state (on and off, on and off, the frequency is very fast, the general flat-panel switching power supply frequency 100 ~ 200KHz, the module power in 300 ~ 500KHZ). So his loss is small, the efficiency is high, the transformer has also been asked to use high permeability materials to do. A little ink, and his transformers is a small, efficiency 80% ~ 90%, it is said that the United States good VICOR module up to 99%, high efficiency switching power supply small size, but the linear power supply than his ripple, voltage and current There is a discount rate adjustment.

Switching power supply regulation tube work in saturation and as the state, which heat a small, high efficiency (75%) and save a large volume of transformers. However, the switching power supply DC output will be superimposed on a large ripple (50mV at 5V output typical), the output of parallel Zener diode can be improved, in addition to the work of the switch will have a lot of spikes, but also need Strings in the circuit to be improved. Relatively speaking, there is no above linear power supply defects, its ripple can be done very small (5mV below).

Linear power and switching power supply installation scene difference

For power efficiency and installation volume requirements of the local switching power supply is better, for electromagnetic interference and power purity requirements (such as capacitance leakage detection) more choice of linear power supply. In addition, when the circuit needs to be isolated when the majority of DC-DC is now used to do the isolated part of the power supply (DC-DC from its working principle is the switching power supply). Also, switching power supply used in high-frequency transformer may be wound up more trouble.

Switching power supply and linear power in the internal structure is completely different, the switching power supply as the name implies switching action, which uses variable duty cycle or frequency conversion method to achieve different voltages to achieve more complex, the larger advantage of high efficiency, general In more than 90%, the shortcoming is that the wave and switching noise are larger, and it is suitable for occasions where the requirements on the wave and noise are not high. However, the linear power supply has no switching action and belongs to the continuous analog control. The internal structure is relatively simple and the chip area is small , Low cost, the advantage of low cost, Wen Bo noise is small, the greater disadvantage is inefficiency. Each of them has its own drawbacks in the application of complementary coexistence!