Design Of Fast Charge Interface Circuit Appilied To The Mobile Terminal Charger

With the rapid development of smartphones,the charging speed of smartphone batteries has been increasingly concerned.In order to improve the charging speed,one after another,the fast charging protocol has been studied and promoted by domestic and foreign researchers.The flyback converter circuit topology is often adopted by conventional charging circuit which is not compatible with fast charging protocol.Therefore,the interface circuit that can be compatible with the fast charge protocol in some ways is widely concerned by researchers at home and abroad.A fast charging interface circuit applied to the mobile terminal charger is designed independently in this thesis.The implementation is proposed for the protocols,such as “Quick-Charge 3.0 A-class”,“Quick-Charge 2.0 A-class” and “USB BC 1.2”.The output voltage of the fast charging circuit is controlled by the fast charging interface circuit's output current,and the glitch is filtered to avoid misoperation due to noise interference.At first,the fast charging protocol is analyzed in detail.Then,the topology of the secondary side regulation(SSR)flyback converter used to the fast charging circuit is selected according to the protocol.On the basis of analyzing the function of fast the charge interface circuit,the digital logic module of the fast charge interface circuit is designed,and the method of the hierarchical structure analysis is adopt for designing the digital logic module.The digital logic module is composed of an input circuit module,a handshake module,a fast charging mode selection module,an output circuit module and an overvoltage detection module,Verilog HDL is used to describe the digital circuit,and the simulation and optimization design is carried out based on Modelsim software.On the basis of the digital module design,the analog part of the fast charging interface circuit is designed,such as bandgap reference module,step current source module,sampling circuit module,oscillator module and power module,etc.Finally,the system level simulation of the fast charging interface circuit is carried out,and the fast charging interface circuit is verified by the field programmable gate array(FPGA).The result of system simulation and FPGA verification shows that: the fast charging interface circuit applied to the mobile terminal charger,which is compatible with Quick-Charge 3.0 A-class,Quick-Charge2.0 A-class,and USB BC 1.2 protocol,is designed successfully.Mode switching glitch filter time is 40 ms,which is greater than 20 ms and less than 60ms;and continue mode glitch filter time is 150?s,which is greater than 100?s and less than 200?s;the minimum output current of the fast charging interface circuit is-14?A,and the maximum value is 70?A.The step output current of the fast charging interface circuit is 2 ?A,and the error is less than 5%,which is conforming to design requirements...