Lead-acid batteries because of its low manufacturing cost, large capacity, inexpensive and widely used. However, if used improperly, it will be greatly shortened life expectancy. Many factors influence the service life of lead acid battery, and a correct charging method, can effectively prolong the service life of the battery. There are several methods for battery charging: Constant current charging method. Constant current charging method is used to adjust the output voltage of the device or change the charging and battery series resistance method, maintain the strength of charging current constant charging method, as shown in figure 2. The control method is simple, but because the battery current capability is acceptable as the charging process gradually decline, to the charging period, the charging current for the electrolysis of water, gas, the air outlet is too, therefore, often selecting phase charging method. Two stage charging method. The method includes two stage...

The integration and miniaturization of high-frequency switching power supply for communication is the main trend of development in the future. The power density will be larger and larger, and the requirements for technology will be higher and higher. At present, the development of high-frequency switching power supply technology for communication mainly includes the following aspects: converter topology, modeling and simulation, digital control and magnetic integration.    1. Converter topologyIn recent years, soft switching technology, power factor correction technology and multilevel technology are hot spots in converter topology. Using soft switching technology can effectively reduce the loss and switching stress of high-frequency switching power supply for communication, which is helpful to improve the efficiency of the converter; PFC technology can improve the input power factor of AC / DC converter and reduce the harmonic pollution to power grid; Multilevel technology...