Smartphone Fast Charge

The smartphone has the characteristics: a large screen，high-frequency，run faster，the multithreaded system open source andothers. And they will become a modern working life essentials. Especiallybecause the system is open source，so that the third-party applicationmarket is extremely strong，these applications have been covering allaspects of life，has made an irreplaceable position in people’s daily lives.At the same time as the third-party applications for increasing hardwarerequirements，making smartphones frequence higher，more and morehigh-performance graphics processing (GPU). Accordingly，the powerconsumption of smartphones is also increasing，the battery charging timeis getting longer and longer，and is beyond the limits of patience.Therefore，how to achieve fast charging of smartphones is imminent，andalso has a large practical significance.According to the working principle and the charging characteristicsof a lithium battery，the impedance characteristic of the mobile phone andcable，and the charger output characteristics in accordance with therapidly charging Markov Law，using trickle chargeâ†'constant currentchargingâ†'constant voltage charging of the charging process，bytheoretical analysis and optimization，to achieve the fast charging ofsmartphones. Throughout the design，selection of the Texas Instruments(TI)，the latest generation of charger BQ2419X series as the basis andcore of fast charging，the BQ2419X Series can support up to4.5A chargeconversion efficiency of more than92%，the impedance of the batteryMOSFET reached12mΩ，the chip is more mature，to ensure fastcharging can be realized，a substantial increase in power efficiency，reduces system heating simplify the custom process to shorten the design cycle，reduce design costs. On this basis，the analysis of the relationshipbetween the impedance of the charging current and the charging path，inorder to obtain a higher charging current，have done a detailed analysisand design of the various parts of the charging path. In order to enablefast charging realize commercial， detailed feasibility studies andcomparison tests are done on various parameters， analysis andoptimization problems found in testing done to ensure a fast chargingsecurity.