Design And Research Of Driving Chip Based On Low-power Wireless Charging System

This paper focuses on the research of low-power wireless charging driving chip,and designs a driving chip which is based on the Qi(A11)standard.This paper mainly focuses on the analysis of the emission power of the low power wireless charging system and the design of the driving chip.The principle and application of low power wireless charging system standard has been discussed.In addition,the paper analyses the frequency and duty ratio of the two parameters for low power wireless charging power by the mathematical method,than finishes the circuit design and Simulation of the main modules of the system.Finally,the layout design is completed.The main work and innovation of this article are as follows:1.In the analysis of low power transmission wireless power system for power adjustment,mathematical analysis of frequency and duty ratio is not achieved by the traditional derivation of vector impedance angle method.It is achieved by circuit performance of capacitance and inductance of the voltage-current characteristics and resonant converter to simplify and unify the different working conditions,which is more conducive to the intuitive mathematical model reference.2.This paper designs a model with a slew rate enhancement circuit capacitor free LDO circuit.While maintaining a low quiescent current and capacitor free conditions,not through the traditional capacitance or improve the LDO system bandwidth,the LDO achieve stability and good transient characteristics.The designed the LDO works in the temperature range of 85~40??-CC and the static current is less than 9.983?A;the minimum dropout voltage is 200mV;the line regulation is less than %0.25V;the load regulation is less than %94.3A;PSRR is more than 25dB;when the rise and fall of time are 10 ns in the simulation,the transient recovery time is less than 3.51?s and the transient voltage overshoot is less than214 mV.3.In this paper,the driving chip is designed by Tsmc 18.0?m Mixed-signal technology,which is suitable for Qi(A11)standard and applied to low-power wireless charging system.Itsinput is controlled by six bits digital signal,and the output phase angle is180?.The frequency range is Hz 205~110kHk z,the step is about 0645.3kHz,the standard rate of frequency accuracy is100%.The output duty ratio range is %50~%10,the step is about.29%1,the duty ratio error is less than %1.The quiescent current is 02.10 mA when the power voltage is 5V.Compare with the traditional low power wireless charging chip architecture,differential ring oscillator is used to replace the original single output oscillator.The chip's architecture doesn't need to lock phase of the oscillation output signals which reduces the difficulty and cost of chip design.