The structure and characteristics of the two types of switching power supplies are described below.
Grounded
Switching power supplies produce more interference than linear power supplies. Electrical equipment that is sensitive to common mode interference should take grounding and shielding measures. According to EMC restrictions such as ICE1000, EN61000, and FCC, switching power supplies adopt EMC electromagnetic compatibility measures, so switch Generally, the power supply should be equipped with EMC electromagnetic compatibility filter. For example, the HA series switching power supply of Lead Huafu Technology can meet the above electromagnetic compatibility requirements by connecting its FG terminal to the ground or to the user's case.
protect the circuit
The switching power supply must have protection functions such as overcurrent, overheating, and short circuit in the design. Therefore, the switching power supply module with complete protection functions should be preferred in the design, and the technical parameters of the protection circuit should match the working characteristics of the electrical equipment. Avoid damaging electrical equipment or switching power supply.
Development trend
The development direction of switching power supply is high frequency, high reliability, low consumption, low noise, anti-interference and modularization. Since the key technology of light, small and thin switching power supply is high frequency, the major foreign switching power supply manufacturers are committed to the simultaneous development of new and highly intelligent components, especially to improve the loss of secondary rectifier devices, and to improve the Ferrite (Mn? Zn) materials have increased technological innovation to improve the high magnetic properties obtained at high frequencies and large magnetic flux density (Bs), and the miniaturization of capacitors is also a key technology. The application of SMT technology has made great progress in switching power supplies. Components are arranged on both sides of the circuit board to ensure that the switching power supply is light, small and thin.
The high frequency of the switching power supply will inevitably innovate the traditional PWM switching technology. The realization of the soft switching technology of ZVS and ZCS has become the mainstream technology of the switching power supply, and the working efficiency of the switching power supply has been greatly improved. For high reliability indicators, US switching power supply manufacturers reduce the stress of the device by reducing the operating current and lowering the junction temperature, so that the reliability of the product is greatly improved.
Modularity is the general trend of the development of switching power supplies. Modular power supplies can be used to form a distributed power supply system, which can be designed as an N+1 redundant power supply system and realize capacity expansion in parallel mode. In view of the shortcoming of high operating noise of switching power supply, if the pursuit of high frequency alone, the noise will also increase, and the use of partial resonant conversion circuit technology can theoretically achieve high frequency and reduce noise, but some There are still technical problems in the practical application of resonant conversion technology, so a lot of work is still needed in this field to make the technology practical.