Various losses within a switching power supply
Jan 11,2024

A switching power supply is an electrical device that converts input electrical energy into output electrical energy. During this conversion process, various losses are generated. In this article, we will introduce the various losses inside the switching power supply, including switching device losses, conduction losses, switching efficiency, and losses in the voltage reduction process.


First, let's understand the switching device loss. Switching power supplies usually include devices such as switching tubes and diodes. In the working process, the switching tube is used to control the flow of electrical energy, when the switching tube is in the conduction state, there will be a certain voltage drop and power loss. When the switching tube is in the off state, there will be a certain current circuit is cut off, thus generating switching losses. The conduction and shutdown of the switching tube are carried out alternately, thus generating a frequent switching process, resulting in a relatively large loss of the switching tube.


Secondly, conduction loss is also an important loss inside the switching power supply. Conduction loss refers to the current in the switching tube and diode and other devices in the internal conduction process of the power loss. During the operation of a switching power supply, the current is constantly switched back and forth between the switching tube and the diode. Due to the presence of components such as resistance, inductance and capacitance, there is a certain amount of power loss during the conduction of the current. The magnitude of the conduction loss depends mainly on parameters such as the size of the current and the resistance of the power device.


In addition, switching efficiency is also an important indicator within the power supply. Switching efficiency refers to the effective degree to which a switching power supply converts input electrical energy into output electrical energy. Typically, the higher the efficiency of a switching power supply represents the lower its internal losses. The formula for calculating switching efficiency is: switching efficiency = output power / input power. In practice, in order to improve the switching efficiency, methods such as increasing the switching frequency, selecting low-loss devices and rationally designing the circuit can be used.


In the step-down process, there are also some losses. For example, between the input and output of the switching power supply, there is usually an inductive device used to realize the voltage reduction function. In the process of voltage reduction of the inductor device, some losses are generated due to factors such as the internal resistance and self-inductance of the inductor device. In addition, the switching power supply also needs to use the filter capacitor to smooth the output voltage, in the case of battery charging and current mutation, the discharge and charging process of the filter capacitor will also have a certain power consumption.


In summary, switching power supplies have a variety of internal losses such as switching device losses, conduction losses, switching efficiency and losses in the buck process. In order to improve the efficiency of the switching power supply and reduce losses, some measures can be taken, such as optimizing the circuit design, selecting low-loss devices and controlling the switching frequency. The efficiency and reliability of switching power supplies can be further improved through continuous technological improvement and research and development to meet the needs of various applications.

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