BQ24185

The bq24185 is a compact, flexible, high-efficiency, USB-friendly switch-mode charge management device for single-cell Li-ion and Li-polymer batteries used in a wide range of portable applications. The charge parameters is programmable using an I²C compatible interface. The bq24185 integrates a synchronous PWM controller, power MOSFETs, input current sensing and overvoltage protection, high-accuracy current and voltage regulation, and charge termination, into a small WCSP package.

The bq24185 charges the battery in three phases: conditioning, constant current and constant voltage. Charge current is programmable using the I²C interface. Additionally, the input current can be limited to a host programmable threshold to maintain maximum charge current from current-limited sources, such as USB ports. Charge is terminated based on user-selectable minimum current level. A software watchdog provides a safety backup for I²C interface while a safety timer prevents overcharging the battery. During normal operation, bq24185 automatically restarts the charge cycle if the battery voltage falls below an internal threshold and automatically enters sleep mode or high impedance mode when the input supply is removed. The charge status is reported to the host using the I²C interface. During the charging process, the bq24185 monitors its junction temperature (T_J) and reduces the charge current if T_J increases to 125°C. To support USB OTG peripherals, the bq24185 contains boost circuitry that supplies V_VBUS at 5.05V at up to 300mA by boosting the battery voltage. The bq24185 is available in 25-pin WCSP package.