DS2786

Stand-Alone OCV-Based Fuel Gauge

2-Wire Stand-Alone Fuel Gauge Requires No Learn Cycle to Provide Initial Capacity Estimate or Maintain Accuracy During Use
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Status Explanations for product status codes

Part Number Status
DS2786 Active: In Production. See Ordering Information for details.

Description

The DS2786 estimates available capacity for rechargeable Li-Ion and Li-Ion Polymer batteries based on the cell voltage in the open-circuit state following a relaxation period. The open-circuit voltage (OCV) is used to determine relative cell capacity based on a lookup table stored in the IC. This capability makes accurate capacity information available immediately after a battery pack is inserted. During periods of moderate to high rate discharging, which preclude OCV measurements, the DS2786 uses coulomb counting as a secondary means of estimating relative capacity.

Remaining capacity is reported in percent, along with cell voltage, current and temperature information. Cell characteristics and application parameters used in the calculations are stored in on-chip EEPROM.

The DS2786 is intended for use on the host side of portable devices, though it can also be mounted within a battery pack. Measurement and estimated capacity data are accessed through an I²C interface. Temperature data is available from an on-die sensor. Resistance measurements of a pack identification resistor and pack thermistor are supported by ratiometric measurements on two auxiliary inputs.

Data Sheet

Download this datasheet in PDF formatDownload Rev 8 (PDF, 316kB)
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An evaluation board is available: DS2786EVKIT

NOTE: This product uses the following:
DS2786K_EVKit_Installation_v1_91_092811.zip

Key Features

  • Relative Capacity Calculated from Combination Coulomb Counter and Open-Circuit Cell Voltage (OCV) Battery Model
  • Accurate Warning of Low Battery Conditions Even On First Cycle (No Learn Cycle Needed)
  • 12-Bit Battery Voltage Measurement:
    • ±10mV Accuracy
    • 1.22mV LSB, 0V to 5V Input Range
  • 11-Bit Bidirectional Current Measurement:
    • 25µV LSB, ±51.2mV Dynamic Range
    • 1.67mA LSB, ±3.4A (RSNS = 15mΩ)
  • Current Accumulation Measurement Resolution:
    • ±204.8mVh Range
    • ±13.65Ah (RSNS = 15mΩ)
  • Internal Temperature Measurement:
    • 0.125°C LSB, ±3°C Accuracy
  • Two 11-Bit Aux Input Voltage Measurements:
    • ±8 LSB Accuracy, Ratiometric Inputs Eliminate Supply Accuracy Issues
  • VOUT Pin Drives Resistive Dividers, Reduces Current Consumption
  • 2-Wire Interface
  • Low Power Consumption:
    • Active Current: 50µA typ, 80µA max
    • Sleep Current: 1µA typ, 3µA max
 

Applications/Uses

  • 3G Multimedia Wireless Handsets
  • Digital Audio (MP3) Players
  • Digital Still Cameras
   

Key Specifications:

Battery Monitors, Protectors, and Selectors
Part Number Functions Battery Type Interface User Data Storage
(Bytes)
Parameters Measured VSUPPLY
(V)
VSUPPLY
(V)
Features Oper. Temp.
(°C)
Budgetary
Price
min max See Notes
DS2786  Fuel Gauge
1 Cell Li-Ion
3-Cell NiMH
2-Wire 32 EEPROM
Current
Temperature
Voltage
2.5 5.5
AFE
Digital Current Accumulation
OCV-Based Fuel Gauge
On-chip Remaining Capacity Algorithms
Ratiometric Voltage Inputs
-40 to +85 $1.53 @1k
See All Battery Monitors, Protectors, and Selectors (34)

Pricing Notes:

This pricing is BUDGETARY, for comparing similar parts. Prices are in U.S. dollars and subject to change. Quantity pricing may vary substantially and international prices may differ due to local duties, taxes, fees, and exchange rates. For volume-specific and version-specific prices and delivery, please see the price and availability page or contact an authorized distributor.



Diagram

DS2786: Typical Operating Circuit
Typical Operating Circuit

More Information

New Product Press Release   2007-02-20 ]

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Information Index

Document Ref.: 19-4637 Rev 8; 2009-06-22
This page last modified: 2009-09-01