1 INTRODUCTION

1.1 FEATURES

123• Battery Fuel Gauge for 1-Series Li-Ion

Applications

• Resides on System Main Board

– Works With Embedded or Removable

Battery Packs

• Uses PACK+, PACK–, and T Battery Terminals

• Microcontroller Peripheral Provides:

– Accurate Battery Fuel Gauging

– Internal Temperature Sensor for Battery

Temperature Reporting

– Battery Low Interrupt Warning

– Battery Insertion Indicator

– Configurable Level of State of Charge (SOC)

Interrupts

– State of Health Indicator

– 96 Bytes of Non-Volatile Scratch-Pad FLASH

• Battery Fuel Gauge Based on Patented

Impedance Track™ Technology

– Models the Battery Discharge Curve for

Accurate Time-to-Empty Predictions of–

Automatically Adjusts for Battery Aging,

Battery Self-Discharge, and

Temperature/Rate Inefficiencies

– Low-Value Sense Resistor (10 mΩ or Less)

• 400-kHz I2C™ Interface for Connection to

System Microcontroller Port

• In a 12-Pin NanoFree™ (CSP) Packaging

1.2 APPLICATIONS

• Smartphones

• PDAs

• Digital Still and Video Cameras

• Handheld Terminals

• MP3 or Multimedia Players

1.3 DESCRIPTION

The Texas Instruments bq27505 system-side Li-Ion

battery fuel gauge is a microcontroller peripheral that

provides fuel gauging for single-cell Li-Ion battery

packs. The device requires little system micro-

controller firmware development. The bq27505

resides on the system’s main board and manages an

embedded battery (non-removable) or a removable

battery pack.

The bq27505 uses the patented Impedance Track™

algorithm for fuel gauging, and provides information

such as remaining battery capacity (mAh), state-of–

charge (%), run-time to empty (min), battery voltage

(mV), temperature (°C) and state of health (%).

Battery fuel gauging with the bq27505 requires only

PACK+ (P+), PACK– (P–), and Thermistor (T)

connections to a removable battery pack or

embedded battery circuit. The CSP option is a 12-ball

package in the dimensions of 2,43 mm × 1,96 mm

with 0,5 mm lead pitch. It is ideal for space

constrained applications.