Telecom power supply is an integral part of the communication system. Often called the "heart" of the telecom system. It occupies a very important position in the telecom system. If the telecom power system fails, the quality of the power supply will be degraded or will be interrupted. If the telecom system cannot operate normally, a failure of the telecom system will inevitably occur. As 5G develops rapidly, more stringent requirements are placed on the telecom power supply. The energy consumption of 5G is 2.5~3.5 times that of 4G, so the power supply needs more power. Compared with 3G/4G, the data traffic of 5G becomes more unbalanced. The traffic may be large in certain periods and small in certain periods. This means that the load range of the telecom power supply will be from light load to full load. In order to ensure that the power consumption reaches the minimum under any load for 5G telecom power supply. The requirement of efficiency is not to reach the highest value under a fixed load, but to reach the highest value in a wide range.