The RT9455 is a switch-mode single cell Li-Ion/Li-Polymer battery charger for portable applications. It integrates a synchronous PWM controller, power MOSFETs, input current sensing, high accuracy voltage regulation and charge termination circuits. The RT9455 also features USB On-The-Go (OTG).
The RT9455 optimizes the charging task by using a control algorithm to vary the charge rate via different modes, including pre-charge mode, fast charge mode, and constant voltage mode. The key charge parameters can be programmed via the I2C interface. The RT9455 resumes the charge cycle whenever the battery voltage falls below an internal threshold and automatically enters sleep mode when the input power supply is removed.
Other features include under-voltage protection, over-voltage protection, thermal regulation and reverse leakage protection.
The RT9455 is available in the small WL-CSP-16B 1.7x1.77 (BSC) package.