Principle of primary feedback switching power supply
Switching power supply is a kind of high-efficiency power supply that is often used in electronic equipment. It can convert the input voltage into the output voltage that meets the requirements of the equipment. In switching power supply, primary feedback is a commonly used control circuit, which can adjust the output voltage by adjusting the primary voltage of transformer. This paper will introduce the working principle, circuit structure and application scenarios of the primary feedback switching power supply, and elaborate the working principle of this power supply in detail.
First, the working principle of primary feedback switching power supply
The core part of switching power supply is the switching tube, which can quickly switch the input voltage into a fixed high-frequency pulse, and amplify it through the transformer, and finally supply power to the load through the output circuit. In the primary feedback switching power supply, the primary side of the transformer is equipped with a capacitor and a resistor, which form a feedback network to feed back the primary voltage signal of the transformer to the switch tube, thus realizing the adjustment of the output voltage.
Specifically, when the switch tube is turned on, the input voltage will be converted into a high-frequency pulse, which will be amplified by the transformer and output to the load terminal. At the same time, the capacitor will be gradually charged, and the resistor will form a low-pass filter with the capacitor, so that the feedback circuit will only respond to the average value of the primary voltage. When the load voltage is unstable, the feedback circuit will adjust the primary voltage to keep the output voltage stable.
Second, the circuit structure of primary feedback switching power supply
The circuit structure of primary feedback switching power supply mainly includes switch tube, transformer, load, feedback network and so on. Among them, the switch tube switches high-frequency pulses, the transformer acts as an amplifier and isolator to transmit voltage signals to the load, and the feedback network constantly detects the load voltage and feeds it back to the switch tube to realize the adjustment of the output voltage.
Third, the application scenario of primary feedback switching power supply
Primary feedback switching power supply is widely used in the power supply of electronic equipment because of its high efficiency, portability and reliability. Especially in the occasions that require high stability, fast response speed and high power quality, such as communication equipment, monitoring system, medical equipment, precision instruments, LED lighting and other fields, the primary feedback switching power supply is the primary power supply mode.
