Design Of Low-power And High-reliability Single-cell Lithium-ion Battery Protection Chip

With the increasing popularity of portable electronic products,the power supply market is also rapidly expanding.Compared with traditional secondary rechargeable batteries such as nickel-cadmium batteries and nickel-metal hydride batteries,lithium-ion batteries have a low self-discharge rate,high energy density,no memory effect,long cycle life,and are an environmentally friendly battery with very large Advantage.However,lithium-ion batteries also have some drawbacks.The lithium-ion battery may enter an abnormal state during charging and discharging,which may damage the lithium-ion battery.In order to effectively monitor and protect the lithium-ion battery,and to realize the protection function quickly,accurately,and efficiently,the lithium-ion battery protection circuit must be designed.At present,the protection circuits for lithium ion batteries are basically integrated chips.This article first introduces the domestic and foreign research status and development trends of lithium-ion battery protection chips.Then the system structure of the lithium-ion battery protection chip and the function of each module are introduced,and the various working states of the lithium-ion battery protection chip are analyzed.Then the design and simulation optimization of the internal sub-module circuit of the lithium-ion battery protection chip,the internal structure of the chip mainly includes the band gap reference source,the battery voltage sampling circuit,overcharge voltage protection,overdischarge voltage protection,discharge overcurrent protection,short circuit protection,charger detection and charging over-current detection circuit,oscillator,delay module,over-temperature protection,logic control module circuit,0V forbidden charging circuit and other modules.The chip uses Magnachip's 0.18?m CMOS process,and the circuit is designed and simulated based on the Spectre simulation platform.Through simulation,the chip has a quiescent current of only 2.579?A during normal operation;when in standby,the working current is only 178.38 n A.It can realize basic functions such as over-charge voltage protection,over-discharge voltage protection,charge over-current protection,discharge over-current protection,short-circuit protection and over-temperature protection,0V forbidden charging,etc.It also has high reliability and low power consumption.Therefore,the functions and performance indicators of the lithium-ion battery protection chip designed in this paper have reached the expected requirements.