Design Of High Precision Configurable Protection Chip For Multi-cell Li-ion Battery

Lithium-ion battery is currently the most widely used rechargeable batteries in portable electronic products as well as large-scale electric vehicle,and widely used in the space exploration,maritime exploration and energy storage.However,it is easy to cause spontaneous combustion when the battery overcharges,and cause a change in the characteristics of the battery reduced the service life when the battery over-discharges,so each lithium-ion batteries require a corresponding protection chip to provide chargedischarge protection,which will ensure the safe use of the battery and prolong its service life.This paper combines practical application scenarios to design a lithium battery protection chip having a large practical value.The battery protection chip supported 3-5 batteries in series and multi-chip stacking,in aspect of the battery detection,achieved overvoltage detection,undervoltage detection,overcurrent detection,and short-circuit detection.Through the analysis of lithium practical applications,this paper designed the system architecture of the chip,designed overvoltage detection and undervoltage detection circuits,which joined the resistance trimming network as well as the corresponding trim algorithms to improve detection accuracy,designed overcurrent detection and short-circuit detection circuits,which included some key techniques,such as bandgap reference of multiple output voltages,the delay circuits etc.,and designed an inter-chip cascade circuit to achieve multi-cell lithium battery detection.This paper is based on HHGRACE 0.35μm BCD process to design and simulate submodule and the overall circuits.Simulation results show that the overvoltage detection voltage is 4.2V,overvoltage release voltage is 4.1V,undervoltage detection voltage is 2.75 V,undervoltage release voltage is 3V,the detected voltage errors are less than 10 mV by trimming,overcurrent detection voltage is 100 mV,short-circuit detection voltage is 1V,short-circuit and overcurrent release voltage is 150 mV,overvoltage protection delaytime is 1s,overvoltage release delaytime is 100 ms,undervoltage protection delaytime is 1s,undervoltage release delaytime is 10 ms,overcurrent protection delaytime is 10 ms,short-circuit protection delaytime is 300μs,short-circuit and overcurrent release delaytime is 10 ms,the overall current consumption is 13.13μA during normal operation,5.998μA during undervoltage protection.Theoretical analysis and simulation results show that the chip’s function is normal,performance is better,and design is meeting requirements.