Design And Test Of 16 Channel Li-battery Management Chip Used In BMS

With the development of people's requirement,the quantity of travel tools such as electric bicycle.Its battery manage system,different from mobile phones and other electronic devices,is necessary to manage multiple battery units at the same time.AD7280,ATA6871 can manage 6 cells.ISL8600,LTC6802 can manage 12 cells.But it is hard to manage more because of higher voltage required.Therefore,this paper develops a secure,stable power management chip that can be applied to BMS and support 16 battery units.This paper designs several important modules of the chip,including the band gap reference(BGR)and the linear voltage regulator(LDO)in the power module,the voltage sampling module and the current sampling module and tests after tape-out.The voltage sampling module is directly connected to the li-battery.Because the number of battery management is large,the highest voltage of the chip design is up to 80 V.According to the different working environment of the 16 li-battery cell,5 different VC_MUX are divided into voltage acquisition.The current sampling module is designed with high accuracy and the input range is ±120mV.Switching capacitor is used to form negative feedback loop to adjust the whole circuit.The total offset voltage is integrated and stored in the capacitor in each switch cycle,and cleared in the next cycle.The chip uses Cadence virtuoso software to complete the design,simulation,layout and verification.The simulation results show that the voltage module of the chip has a good temperature characteristic.The current sampling module can reduced the offset voltage higher than 99.2%.The chip test results show that the circuit voltage sampling module has good linearity and linear fitting coefficient is more than 0.999,as well as the current sampling module.After zero-calibration,the data sampling error is less than 1%.