How to choose a switching power supply

When decorating wires, we must also pay attention to the selection of power switches. After all, there are also many power switches, and they correspond to different voltage ranges, power, and load characteristics. The following describes how to choose a switching power supply and what working mode the switching power supply has. In the process of selecting a switching power supply, you can pay attention to these problems, and then choose a regular switching power supply product as much as possible, so that the effect will be much better.

How to choose a switching power supply

When selecting a switching power supply, the input voltage range, appropriate power, load characteristics, and operating ambient temperature should be considered.

1. Choose a suitable input voltage range. Taking AC input as an example, the commonly used input voltage specifications are 110V and 220V, so there are correspondingly three specifications of 110V and 220V AC switching, and universal input voltage (AC: 85V-264V). The input voltage specification should be selected according to the area of ​​use.

2. Choose the right power. The switching power supply consumes a part of the power during operation and releases it in the form of heat. In order to increase the life of the power supply, it is recommended to use a model with an additional 30% output power rating.

3. Consider the load characteristics. In order to improve the reliability of the system, it is recommended that the switching power supply work at 50%-80% load, that is, assuming that the power used is 20W, the switching power supply with an output power of 25W-40W should be selected.

If the load is a motor, light bulb, or capacitive load, the current is large at the moment of startup, and a suitable power supply should be selected to avoid overload. If the load is a motor, the voltage reversal during shutdown should be considered.

4. In addition, the working environment temperature of the power supply needs to be considered, and whether there is additional auxiliary heat dissipation equipment. The derated output of the ambient temperature power supply that is too high a. Refer to the derating curve of ambient temperature versus output power.

What is the working mode of switching power supply

Fixed frequency, pulse width mode, fixed frequency, variable pulse width mode, variable frequency and pulse width mode.

1. The former working mode is mostly used for DC/AC inverter power supply, or DC/DC voltage conversion; the latter two working modes are mostly used for switching regulated power supply.

2. In addition, the output voltage of the switching power supply also has three working modes: direct output voltage mode, average output voltage mode, and amplitude output voltage mode.

3. Similarly, the former working mode is mostly used for DC/AC inverter power supply, or DC/DC voltage conversion; the latter two working modes are mostly used for switching power supply.

According to the way the switching devices are connected in the circuit, the switching power supply can be roughly divided into three categories: series switching power supply, parallel switching power supply, and transformer switching power supply. Among them, transformer-type switching power supply (hereinafter referred to as transformer switching power supply) can be further divided into: push-pull type, half-bridge type, full-bridge type, etc.; according to the excitation of the transformer and the phase of the output voltage, it can be divided into: forward type , Flyback, single-excitation, double-excitation, etc.; if it is divided into uses, it can be divided into more types.

The above introduction is how to choose the switching power supply and what working mode the switching power supply has. When you choose the power switch, you must still see the voltage range and the appropriate power. If it is a relatively high voltage, you must also understand the load capacity of these materials. In addition, in fact, the switch has a variety of working modes, including fixed frequency, pulse width, etc., so it should be selected according to the range of use of the home.