Research And Design A New Type Of Management Chip For Mobile Power Pack

Mobile Power Pack can charge to mobile phones,tablet PCs and other digital devices anytime and anywhere,as is a portable charger.Lithium-ion batteries is the most widely used as a storage unit.Charge and Discharge management is the essential part in battery management.Fast,safe and high efficient management of chip plays a vital role in good performance and extend battery life.This paper describes a superior performance,widely application,low cost mobile power pack charging and discharging management chip design and implementation.In this paper,combined with full-custom design concept,completed from the bottom of the module circuit to the top with the forward design,from the charging and discharging to describe.For charging: the system adopted linear charging mode.To achieve a timely monitoring of battery voltage,with different voltages to adopted trickle charging,constant current charging,constant voltage charging,charging stop and with the function of overcharging protection,over discharge protection,short circuit protection,over temperature protection.For discharging: To boost the voltage with the methods of synchronous rectifying DC-DC,to improve convention efficiency adopted the mixed modulation of PWM and PSM,using of the sub-driving to open/ close the power tube,the cycle-by-cycle detection of inductor current to achieve over-current protection and to prevent the current backflush phenomenon in light DCM mode of light load,then with the short-current detection and self-recovery,overvoltage and over temperature protection,In order to ensured the safety and reliable of chip.In addition,making changes the views of external resistors can be adjusted the constant current charging current of the chip.All power tubes be integrated into the chip,improves the integration degree,low cost.Using on-chip trimming method to calibrate the reference source,it can effectively ensured the accuracy of output voltage.Also a new shorted-current protection of output circuit is presented to protect the chip.Finally,the circuit of this paper was based on CMOS 0.5μm process,use the Cadence tool to complete the circuit design,simulation,layout design and verification.From the simulation results,the changing curve of the charging current was changed with the voltage of battery in the process of charging,the changing curve of the output voltage was moved with size of load,temperature and others,a variety of protection methods and performance indicators are also in perfect agreement with the design requirement well.This chip is suitable for the single Li-ion battery with linear charger and the boost converter with 5V output and the chip has been taped out.