Research On Multi-Mode Fast Charging And Wireless Charging Technique For Mobile Devices

A variety of mobile applications such as mobile phones, tablet computers, have gained more popularity and even become necessities of people’s life. However, due to the limited battery capacity, how to charge these devices in a quick, efficient and convenient way has become an issue of concern to the industry.Considering this, this thesis carries out the researches on both wired fast charging and wireless charging schemes for mobile terminals. The thesis utilizes the constant current/constant voltage multi-modes featuring fast charging and high efficiency as well as wireless powering to solve problems of traditional charging methods such as slow charging speed and long charging period and to improve the mobility and convenience of charging mobile terminals.The main contributions of this thesis are as follows:1.Ini the scopes of wired charging schemes for mobile terminals, AC-DC switched power converter is used. The switched power supply applies fly-back converter; the control scheme chooses current feedback PWM modulation and the converter operates in constant current\constant voltage mode to improve the charging speed and the response performance.The control chip is designed with CSMC 1μm 40V process. The designed chip has been taped out and the testing results show that the switched power supply proposed in this thesis has realized fast charging for mobile terminals.2. For a key technology of wireless charging--how to keep the system working in the optimal conditions during the whole working process, this thesis puts forward a scheme with the new structure of inverse Class-E power amplifier. It is shown that when the MOSFET of the inverse Class-E power amplifier meets the conditions of zero current switching (ZCS) and zero current derivation switching (ZCDS), the system can keep working in the optimal state. And the corresponding closed-loop control scheme is put forward in which the output load is regarded as independent variables. When the load changes, the power amplifier can remain in the optimal working state by adjusting the duty cycle and frequency of the MOSFET driving voltage.The design of the control circuit is based on SMIC 0.18μm 3.3V process. The simulation results show that when the output load changes in the range of 20%, the inverse Class-E power amplifier can keep working in the optimal conditions.