Research And Design Of A Multi-loops Compound Feedback Charging Circuit For Battery

With the development of today's electronic technology industry,all kinds of mobile portable devices such as laptops,mobile phones and other products are widely used.Moreover,the function of the electronic equipments are more complex and diverse,which make the research of power supply battery is developing towards smaller volume,larger capacity and better performance.Compared with other rechargeable batteries,lithium-ion battery's green and non-toxic harmless characteristics make it a preferred power supply in mobile devices.At the same time,due to the wide application of lithium battery,the research of lithium-ion battery charging management technology is also deeply developing.Aiming at the disadvantages of the charging management chip having existed,such as insufficient charging efficiency,high power consumption and complicated designs of the circuits.This paper presents a multi-loops compound switching battery charging circuit,which provides a single-chip solution for the battery pack and standalone battery charger.In order to reduce the circuit area and the power consumption of the circuits with the predominant performance of the system and improve the charging efficiency,the four feedback loops are integrated in the charging circuit.In addition,the multi-loops compound charging loop is modeled and the overall structure of the system and the main sub-circuits in the multi-loops compound feedback charging controlling circuits are analyzed and designed,including constant current circuit,limiting circuit of charging current,inputting current limiting for reference circuit,limiting circuit of inputting current,multi-loops composite feedback circuit.Finally,the paper completed the whole process from the charging loop modeling,circuits design and simulation,overall verification of the system to the chip manufacture.The charge chip designed and manufactured with 0.18?m 5V CMOS process.Simulation and testing show that the switching frequency is 1MHz,the efficiency of the system is up to 96% with the input voltage is 5V,the charging current is 2A and the battery voltage changes from 3V to 4.15V;When the input voltage changes from 4.75 V to 5.1V in 50?S,the system has a linear transient response and can work normally.To sum up,the function and characteristics of the lithium battery charging circuit in this paper works properly,and have a good stability of the loop,so as to verify the effectiveness of the design of multi-loops feedback charging circuit.