The Design Of 90W Composite Charging Mobile Power Supply

This thesis is to design a kind of portable mobile power supply. Mobile power was designed which can realize the different output circuit. After experimental test the system prove to be safe and reliable. The system consists of charging circuit,20v, 12v,5v output circuit and protection circuit. Otherwise it can display how much battery remains.In order to select the appropriate topology structure for this design,a detailed analysis about the topology of switch power supply was done. Chip CN3705 was used to realize lithium battery charging circuit, which can be charged by adapter and use green cleaning of solar charging. Charging state can be divided into two stage include constant current and constant voltage. The chip can protect the circuit very well. Chip UC3843 function and detailed introduces on the external circuit design was analyze, the circuit realized the maximum output power of 90w. This paper expounds the step-down chip LM2576 internal structure and function, and designs a stable step-down module. MCU PIC16F616 of circuit can realize the function of protection,power display, prolong the service life of the battery and increase the safety of the circuit. The paper introduces in detail the design of the high-frequency inductors, lists some common magnetic core material, and analyzes its advantages and disadvantages. Meanwhile it also analyzes the work in the design of the high frequency inductive pattern, derives the calculation of the inductance, and calculates the wire diameter. Finally schematic diagram was designed and then PCB design was carried out. A lot of experimental test was done which relates to temperature and efficiency.This thesis can use the solar charge in outdoor. Meanwhile the car power charge and commercial power charge can be used, which is the major characteristic.Compared with the traditional 10w to 20w output power of mobile power supply, the design of the power output is up to 90w, which can provide power to high power electronics products such as notebook computer, it has three output interface, namely 5v,12v,20v three-way voltage output, which can meet people’s needs with different electrical charge.