Qatar 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 LED advertising screen power supply equipment will be reduced to the maximum, which is not conducive to miniaturization. When the switching LED advertising screen 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.
Ring current backup
The ring current generator is mainly used in the telephone exchange exchange to provide ringing to the telephone users, and is generally used in a biased state. Bias can be divided into positive bias and negative bias. In order to improve the reliability of the ring current system, the ring current needs to be backed up. Installation and maintenance of module power supply
Since the types, series and specifications of the modular power supplies produced by various companies are difficult to count, their functional characteristics and physical characteristics are not the same, so they are also different in installation, use and maintenance, but the following aspects should be paid attention to
2. Qatar Disadvantages of choosing an AC-DC control IC with a switching frequency higher than 135K
When testing electronic and electrical equipment, the electronic and electrical equipment shall be tested for conducted interference voltage emission at its LED advertising screen 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 LED advertising screen power supply is close to 150K, and the more difficult it is to deal with the conducted disturbance.