Ireland the switching frequency of the AC-DC switching power supply module?(2)

Ireland Choosing the switching frequency of the 24V input power supply does not mean choosing the switching frequency of the 24V input power supply with a good switching frequency, but the choice is suitable for your own use. Most of the current market is like this. The frequency of the AC-DC switching 24V input power supply module is between 50K and 135K, and this frequency range can meet most applications. Let's discuss it. Some of the problems that AC-DC encounters when choosing switching frequency:

1. Why generally do not choose a switching frequency lower than 50K

Due to the wide variety of integrated circuits used in communication equipment, their power supply voltages are also different. In the communication power supply system, a high-frequency DC-DC isolation module power supply with high power density is used, which is converted from the intermediate bus voltage (usually 48V DC) to Various DC voltages are required, which can greatly reduce losses, facilitate maintenance, and are very convenient to install and increase. Generally, it can be directly installed on the standard control board, and the requirement for the secondary power supply is high power density. Due to the continuous increase of communication capacity, the capacity of communication power supply will also continue to increase.

We know that the lower the switching frequency, the smaller the switching loss, but on the other hand, with the reduction of the switching frequency, the volume of the 24V input power supply equipment will be reduced to the maximum, which is not conducive to miniaturization. When the switching 24V input power supply is working, due to the switching of the switching device, the magnetic core will vibrate, and the frequency range that the human ear can hear is about 20~20000Hz. In order to avoid audible noise, we usually choose to stay away from the 20 frequency KHz.