The progress of human society can not be separated from the efforts of all walks of life in society, the upgrading of a variety of electronic products can not be separated from the efforts of our designers, in fact, many people do not go to understand the composition of electronic products, such as switching power supplies and transformers.

Switching power supply refers to the DC voltage obtained after rectifying the power supply. The voltage is cut into a rectangular wave by turning on and off the switch (of course, the actual waveform is not an ideal rectangular wave, but overshoot will occur). What this means is to cut high energy into countless low energy and then pass it to the output. The output terminal will be fed back to the input terminal through the output voltage level (adjusting the cutting frequency and the width of the cutting duty cycle) to achieve the purpose of stabilizing the output voltage.

The LED switching power supply has a circuit that controls the switching tube to achieve high-speed passing and cutting. It converts direct current to high-frequency alternating current to convert the converter to generate one or more sets of voltages. What is the purpose of the switching power supply? The reason for the conversion to high-frequency alternating current is that high-frequency alternating current exists in the transformer. The efficiency in the circuit is higher than the commercial power supply 50Hz or 60Hz. Therefore, the size of the switching power supply transformer can be small, it will not be very hot when the switching power supply is working, and the product price is lower than the power frequency DC stabilized power supply.

The switching power supply can smoothly change the working voltage within the necessary range into a very accurate bottom voltage or high voltage (such as 120V-350, the output working voltage can be smoothly controlled at the necessary working voltage with no difference of 0.6V between the positive and negative poles).

Generally, it can be concluded that the switching power supply first converts alternating current into alternating current, and converts alternating current into higher frequency alternating current according to the output power of the switching tube. According to the high-frequency transformer, the working voltage conversion is not only high in efficiency, but also high in frequency. The volume is greatly reduced, and the loss of copper and iron is also saved. Since the switch tube operates according to the output power, when the current amount is small, the switch tube is turned on at a faster speed and can only maintain the output working voltage. When the load is large, the switch tube works continuously while maintaining the output voltage.

A transformer is an electrical device used for power conversion. It is an essential and important equipment in the power grid. It can convert alternating current of one voltage and current into alternating current of another voltage and current of the same frequency. Transformers are used in all electronic products. Its principle is very simple, but according to different occasions (different uses), the winding process of the transformer will have different requirements. The main functions of the transformer are: voltage transformation: impedance transformation isolation, voltage stability (magnetic saturation transformer), etc.

Transformer is a device that converts voltage, current and impedance according to the principle of electromagnetic induction. The primary side of the transformer is used in the AC circuit. A switching power supply is a power supply that uses modern power electronics technology to control the on-and off-time ratio of switching transistors to maintain a stable output voltage. Switching power supply can be divided into two categories: AC/ DC and DC / DC; switching power supply can be divided into two categories. Electrical isolation according to input and output can be divided into two categories: one is isolated, called isolated DC/DC converter; the other is isolated DC/DC converter. The other one is not isolated and is called a non-isolated DC/DC converter.

Since the voltage control of the switching power supply is realized by adjusting the turn-on time or frequency of the power semiconductor device by adjusting the turn-on time or frequency of the power semiconductor device, there is no iron loss and copper loss, and component loss can be reduced. ignored, which is more efficient than transformers.; Since it only has components and circuit boards, it is small in size and light in weight. The size of the switching power supply is small, the power is related to the core transformer and the control method, the electromagnetic interference is large, and the ripple coefficient is large.

Especially in the field of audio and video, it is very sensitive to electromagnetic interference. In the sound, it is not pure, there may be a silky sound. In video watches, it is very sensitive to electromagnetic interference.

Transformer power supply online. It looks troublesome, and the power depends entirely on the transformer and regulator. Although the efficiency is low, no additional interference is introduced, that is, the electromagnetic interference is very small, and the ripple coefficient is very low and negligible. For monitoring, there is nothing better than this advantage. Image quality has a lot to do with power. Especially for small-amplitude analog signals (audio and video sources, etc.), the power requirements are very high, so some enthusiasts will use transformers instead of switching power supplies. Since the transformer is an "electromagnetic electric" conversion process, it is impossible to avoid the existence of iron loss and copper loss.

This article can only lead everyone to have a preliminary understanding of switching power supply and transformer, which will be helpful for everyone to get started. At the same time, it needs to be constantly summarized, so as to improve professional skills, and welcome everyone to discuss some knowledge points of the article.