Switch Mode Power Supply (SMPS) is an efficient power conversion device widely used in various electronic products and equipment. Compared with traditional linear power supplies, SMPS uses switching elements for voltage conversion, thus achieving efficient energy utilization, small size and light weight. This article will explore why SMPS is called "switch mode power supply" and further understand its practical application value by analyzing its working principle, efficiency advantages and applications in common equipment such as school network laptop charging cabinets, 3D printers, embroidery machines and agricultural irrigation equipment.

What is a switch mode power supply? How is it different from a linear power supply?

To understand why SMPS is called a "switch mode power supply", you first need to understand the difference between it and a traditional linear power supply and the difference in the working principle of the two.

How Linear Power Supplies Work

Linear power supplies reduce voltage by adjusting the resistance of electronic components. When the input voltage is higher than the required output voltage, the linear power supply stabilizes the output voltage by converting the excess voltage into heat. Although this process is simple, a large amount of electrical energy is lost in the form of heat during the energy conversion process, resulting in low efficiency of linear power supplies, especially in high-power applications. In addition, heat dissipation issues also require linear power supplies to be larger in size, which is not suitable for small devices.

Working principle of switch mode power supply

In contrast, SMPS controls the transmission of electrical energy by switching between "on" and "off" states through high-speed switching elements (such as MOSFET). When on, the current passes, and when off, the current is interrupted. The efficiency of energy conversion is very high, and there is almost no heat loss. The core feature of SMPS is that it relies on high-speed switching action to regulate electrical energy instead of relying on resistance. Therefore, SMPS greatly improves efficiency in energy utilization, and can convert input voltage to a voltage more suitable for output requirements by controlling energy storage elements such as inductors, capacitors and transformers.

Because of this working method of regulating by "switching", SMPS is named "switch mode power supply".

Efficiency advantage

The biggest advantage of SMPS over linear power supply is energy efficiency. The efficiency of traditional linear power supply is usually between 50% and 60%, while the efficiency of SMPS is usually as high as 80% to 90%. This means that for the same power input, SMPS can convert more electrical energy into the output required by the device, and the energy loss is greatly reduced.

How does the switch of SMPS work? Why is its switching frequency so important?

In SMPS, the high-speed operation of the switching element is its core feature, and the switching frequency directly affects the performance, size and efficiency of the power supply. Understanding how the switch works and its importance will help to better apply and optimize the use of SMPS.

Basic working mode of the switch

The switching element in SMPS, such as MOSFET or transistor, switches between on and off at high speed when working. When the switch is on, the current provides energy to the load through the inductor or transformer, and stores energy at the same time; when the switch is off, the energy stored in the inductor is released to the load through the diode to ensure the continuous supply of current. This high-frequency switching enables the power supply to achieve stable power output through the energy storage and release process in a short time.

The importance of switching frequency

The switching frequency is usually between several thousand hertz and several megahertz. The higher the frequency, the smaller the required energy storage element (such as inductor, transformer). This is one of the reasons why switching power supply is smaller than linear power supply. In small devices, such as school network laptop charging cabinets, 3D printers, etc., high switching frequency allows the power supply unit to be smaller in size while still providing stable power to the device.

For example, in a school's network laptop charging cabinet, multiple devices need to be charged at the same time, requiring the power system to provide a stable low-voltage output. Through high-frequency switching, SMPS can quickly adjust current delivery to ensure that there is no overheating or voltage fluctuation during the charging process.

Cooperation between switch and control circuit

The control circuit of SMPS optimizes the power output according to the change of load by adjusting the switching frequency and duty cycle. For example, SMPS can adjust the on-time of the switch according to the load demand to reduce unnecessary energy consumption. For devices such as 3D printers and embroidery machines that require high voltage accuracy, this real-time adjustment function of SMPS can ensure the stable operation of the machine and avoid voltage fluctuations affecting printing or embroidery accuracy.

Why is SMPS much more efficient than linear power supply?

The reason why SMPS can stand out among many power supply solutions is that it has a very significant advantage in efficiency. Compared with linear power supply, the design of SMPS avoids a lot of energy loss, allowing it to use less power with the same power output.

Reduce heat loss

In linear power supply, excess voltage is released in the form of heat energy through transistors or resistors, which means that a lot of power is wasted. The switching element of SMPS has almost no resistance when it is turned on, so the current can pass smoothly; when it is turned off, the current stops completely and there is very little energy loss. Therefore, switching mode power supply generates almost no noticeable heat when working. This is especially important in an environment where multiple devices are working at the same time. For example, in a school network laptop charging cabinet, when multiple laptops are charged at the same time, SMPS can effectively reduce the risk of power overheating and extend the service life of the equipment.

Efficient energy transmission

SMPS adjusts the transmission and storage of electrical energy through switching frequency, so that the input voltage can be quickly converted to the required output voltage. For example, in a watering machine system, SMPS ensures the smooth operation of the water pump by adjusting the power output, and will not cause water pump failure due to voltage fluctuations. This efficient energy transmission method allows SMPS to maintain high efficiency even under large current loads, unlike linear power supplies that require additional heat dissipation design.

Dynamic load adjustment

Modern SMPS also has intelligent control functions that can adjust the power output in real time according to load changes. For example, when using an embroidery machine, the load demand may vary due to different working conditions. SMPS can automatically adjust the power output to ensure that the motor can obtain a stable power supply when running at high speed, and automatically reduce energy consumption under low load conditions to avoid unnecessary waste.

Why is SMPS widely used in equipment such as school network laptop charging cabinets, 3D printers, embroidery machines and watering machines?

As SMPS technology matures, it plays an increasingly important role in various application scenarios, especially in equipment with high power demand, such as school network laptop charging cabinets, 3D printers, embroidery machines and watering machines. The high efficiency and miniaturization of SMPS make it an ideal choice for these devices.

School Network Laptop Charging Cabinet

Schools often need to charge a large number of laptops at the same time. Traditional linear power supplies may be inefficient and heat up due to excessive current demand, while SMPS can provide stable and efficient power through high-speed switching actions. Its advantages include reducing overheating problems, improving charging efficiency, shortening charging time, and ensuring that students can use the equipment in a timely manner.

3D printer

During the working process, 3D printers have very high requirements for the stability of power supply, and any voltage fluctuation may affect the printing effect. In such applications, SMPS can not only provide stable power supply, but also dynamically adjust the output power according to the load changes during the printing process to ensure that the printer motor and control system are always in the best working state.

Embroidery machine

As a precision machine, the embroidery machine has strict requirements on the driving voltage of the motor. SMPS can provide precise power control for the embroidery machine to avoid deviations or machine shutdowns during the embroidery process due to voltage fluctuations. In addition, the high efficiency and energy saving characteristics of SMPS also enable it to maintain low temperature operation during long-term operation to avoid overheating of the machine.

Watering machine

In the agricultural irrigation system, the power supply of the water pump is the core of the system. SMPS can adjust the power output according to the actual needs of the irrigation machine to ensure the normal operation of the water pump. Especially in remote areas, when the power supply system is unstable, the efficient energy conversion capability of SMPS can ensure that the water pump continues to work, and can still provide stable output power even if the input voltage fluctuates. In addition, SMPS can effectively reduce energy loss in the irrigation system and extend the battery or power supply system life. This is particularly important for agricultural irrigation systems that rely on solar or wind power, because the power output of these renewable energy sources is often unstable, and SMPS can help stabilize the output voltage and ensure the stability of the irrigation system.

Why does the switch-mode power supply still occupy an important position in the future development?

With its high efficiency, compactness and flexibility, the switch-mode power supply will continue to maintain an important position in various fields in the future. As the demand for more efficient electronic devices increases, SMPS will continue to develop, especially in applications such as school equipment, 3D printing technology and agriculture, and its prospects are very broad.

Higher conversion efficiency

With the application of new materials and technologies, the efficiency of SMPS will continue to increase. For example, the introduction of new semiconductor materials such as gallium nitride (GaN) and silicon carbide (SiC) will further increase the switching frequency and efficiency of SMPS, reduce switching losses and increase the speed of power conversion. Future SMPS will be able to provide higher power and stability while maintaining miniaturization, adapting to the increasingly high power requirements of devices such as school network laptop charging cabinets and 3D printers.

Intelligent and automated control

The development of SMPS will also make progress in the field of intelligent and automated control. By introducing intelligent control systems, SMPS can perform more precise power management based on real-time load changes. For example, future 3D printer power supplies may have intelligent monitoring functions that can automatically adjust the output voltage and power according to the printer's working status, thereby improving printing quality and reducing energy waste. In school charging equipment, intelligent SMPS can also adjust the charging current according to the battery status of the device to ensure fast and safe charging.

Integration with renewable energy

The efficient energy conversion capability of SMPS makes it a key component of renewable energy systems. For example, in agricultural irrigation systems, solar or wind energy can provide power for SMPS, and SMPS can efficiently convert these highly volatile direct currents into stable power for water pumps. In the future, with the application of more green energy, SMPS will play a more important role in improving energy utilization, reducing power waste and promoting sustainable development.

Wide range of application scenarios and flexibility

The flexibility of SMPS enables it to adapt to a variety of application scenarios, whether it is used in homes, schools, or industrial equipment. Especially in scenarios with strict requirements on energy utilization, the high efficiency and miniaturization design of SMPS bring great advantages. For example, in the future, school network equipment may need to provide power support for more devices at the same time, and the compact and efficient design of SMPS will further enhance the load capacity of the system.

Conclusion

Switched mode power supply (SMPS) has become an indispensable component of various modern electronic devices due to its unique switching working mode and efficient energy conversion capability. Compared with traditional linear power supplies, the efficiency, compactness and stability of SMPS make it widely used in school network notebook charging cabinets, 3D printers, embroidery machines and agricultural irrigation equipment.
In addition, with the continuous development of new materials and intelligent control technology, SMPS, as a kind of 24Vdc power supply, will have a wider range of applications and its performance will be further improved. Whether under the requirements of energy saving and environmental protection or in the demand for efficient power supply, switch mode power supply will continue to play an important role and help the development of all walks of life.