Syria the switching frequency of the AC-DC switching power supply module?(3)

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 48V input power supply equipment will be reduced to the maximum, which is not conducive to miniaturization. When the switching 48V 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.

2. Syria Disadvantages of choosing an AC-DC control IC with a switching frequency higher than 135K

(9) For the high-voltage module power supply, do not touch the high-voltage dangerous area during use and within 10 minutes after the power outage.
(10) Purchasing principle of module power supply: Generally, switching power supply should be selected for larger power, and linear power supply should be selected for smaller power.
(11) The module power supply cannot be forcibly dismantled, and it will be damaged if it is forcibly dismantled.

When testing electronic and electrical equipment, the electronic and electrical equipment shall be tested for conducted interference voltage emission at its 48V input power supply terminal. Although the test frequency bands of different standards are different, the test frequency bands of most products are 150K~30M. It can be seen from the lower limit of the test frequency that the operating frequency of the switching 48V input power supply is close to 150K, and the more difficult it is to deal with the conducted disturbance.