System-Side Impedance Track™ Fuel Gauge
• Battery Fuel Gauge for 1-Series Li-Ion
• Resides on System Main Board
– Works With Embedded or Removable
• Microcontroller Peripheral Provides:
– Accurate Battery Fuel Gauging
– Internal Temperature Sensor for Battery
– Battery Low Interrupt Warning
– Battery Insertion Indicator
– Configurable Level of State of Charge (SOC)
– 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
– Automatically Adjusts for Battery Aging,
Battery Self-Discharge, and
– Low-Value Sense Resistor (10 mΩ or Less)
• 400-kHz I
C™ Interface for Connection to
System Microcontroller Port
• In a 12-Pin NanoFree™ (CSP) Packaging
Please be aware that an important notice concerning availability, standard warranty, and use in critical applications of Texas
Instruments semiconductor products and disclaimers thereto appears at the end of this data sheet.
Impedance Track, NanoFree are trademarks of Texas Instruments.
I2C is a trademark of Philips Electronics.
PRODUCTION DATA information is current as of publication date.
Products conform to specifications per the terms of the Texas
Instruments standard warranty. Production processing does not
necessarily include testing of all parameters.
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system-side Li-Ion battery fuel gauge is a
microcontroller peripheral that provides fuel
gauging for single-cell Li-Ion battery packs.
micro-controller firmware development. The
bq27505-J4 resides on the system’s main
board and manages an embedded battery
(nonremovable) or a removable battery pack.
The bq27505-J4 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-J4
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 2.43mm × 1.96mm with 0.5mm
lead pitch. It is ideal for space constrained
Figure 1-1. Typical Application
SLVSA40 – DECEMBER 2009
Single Cell Li-lon
Copyright © 2009, Texas Instruments Incorporated