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.


  • Cellular Telephones
  • Personal Information Appliances
  • MP3 Players
  • Portable Instruments
Key Spec.
Status NRND
Recommended Alternative  RT9458
Vin (min) (V) 4.3
Vin (max) (V) 6
Battery Charge Voltage (max) (V) 4.45
Battery Charge Current (max) (A) 1.55
Status Indicator No
Charger Type Switching
Input Source AC Adapter;USB
Features Adjustable Current Limit;Built-in Bootstrap Switch;Cycle-by-Cycle Current Limit;I2C;Internal Compensation;OCP;OVP;UVP
Package Type WL-CSP1.7x1.77-16
Built-in Power MOSFETs Yes
  • Support Quick Start for Charger
  • High Accuracy Voltage/Current Regulation
  • Input Current Regulation : 100mA/500mA/700mA/1A
  • Minimum Input Voltage Regulation : 4V/4.25V/4.5V
  • Charge Voltage Regulation Accuracy : ±1% (0 to 85°C)
  • Charge Current Regulation Accuracy : ±5%
  • Built-In Input Current Sensing and Limiting
  • Integrated Power MOSFETS for up to 1.55A Charge Rate
  • Integrated Sensing Resistors for Charging Current Sensing
  • Synchronous 1.5MHz Fixed Frequency PWM Controller with up to 95% Duty Cycle
  • Reverse Leakage Protection to Prevent Battery Drainage
  • Thermal Regulation and Protection
  • Over-Temperature Protection
  • Input Over-Voltage Protection
  • IRQ Output for Communication with I2C
  • Automatic Charging
  • RoHS Compliant and Halogen Free
TitleLast UpdateDownload
Switch-Mode Single Cell Li-Ion Battery Charger with USB-OTG2013/12/25
Additional Documents
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Power Management Components for Lithium-Ion Battery Powered Applications