Design Of A Lithium-ion Battery Charging Management Chip

Lithium-ion batteries is the most widely used rechargeable batteries in portableelectronic products. Moreover, with increasing battery capacity, lithium-ion battery willbecome one of the main power of electric vehicles in twenty-first Century, and will beused in satellites, aerospace and energy storage. As the reason of the electrical proper-ties of lithium-ion battery, almost every piece of lithium-ion batteries need a chargemanagement chip to provide the charge and discharge protection to extend their servicelife. This paper describes a low cost, widely used, excellent performance lithium-ionbattery charging management chip design and implementation.Adopted full-custom design thought, completed the circuit forward design，achieved over discharge protection, overcharge protection, short circuit protection, overtemperature protection and trickle charge, constant current charging, constant voltagecharging control functions. The MOS transistor inside the chip used to drive thecharge transistor can withstand high voltage up to30V. Without expansion of the cir-cuit, the chip can be designed as multiple-series battery charging circuit. Low voltagelinear voltage regulator integrated inside the chip, improves the integration degree, sothat the chip has a smaller size, lower cost. Chip peripheral circuits can be designed aslinear control or PFM control, and the application circuit is simple. In addition, makingchanges of the resistors in the external application circuit can be adjusted constantcharging current, pre-charge (trickle charge) cut-off voltage, constant voltage chargingvoltage and the current used to judge whether the battery is full. This makes the chip hasa strong applicability, can be used in many different occasions.The chip is designed by CSMC0.5um DPTM Mixed Signal process, use the Ca-dence tool to complete the circuit design, simulation, layout design and verification.Simulation results show that when the battery temperature detection voltage is greaterthan4.51V, the charge termination; when the battery temperature detection voltage isgreater than0.05V and is less than0.5V, the charging current is24mV/Rs; when thebattery temperature detection voltage is greater than0.5V and is less than4.51V, thechip system work normally, then trickle charge current is24mv/Rs,the voltage used todetermine the end of the pre-charge voltage is0.61V, constant charging current is240mv/Rs, constant charging voltage charging is1.21V, the current used to judge whether the battery is full is24mV/Rs, these parameters are in line with design specifi-cations, and the battery charging curve is also consistent with the design expectations.After the success of the layout design simulation and verification, export GDS docu-ment and send it to foundry for tapping out.