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DS2786: Stand-Alone OCV-Based Fuel Gauge Data Sheet (Rev. 8)6/22/2009PDF311K
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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Overview
Features and Benefits
- 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
Product Details
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.
Applications
- 3G Multimedia Wireless Handsets
- Digital Audio (MP3) Players
- Digital Still Cameras
Product Categories
Product Lifecycle
Production
At least one model within this product family is in production and available for purchase. The product is appropriate for new designs but newer alternatives may exist.
Evaluation Kits (1)
Documentation & Resources
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DS2786 Reliability Data1/12/2023PDF23K
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Demonstrating Green Technology with Apples, Oranges, Lemons, and Limes10/10/2011
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Using the DS2786 Battery Fuel Gauge in the Host Side of a 2-Cell Battery Application5/6/2008
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Characterizing a Lithium-Ion (Li+) Cell for Use with an Open-Circuit-Voltage (OCV) Based Fuel Gauge3/10/2008
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Programming and Testing a DS2786-Based Circuit11/26/2007
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Using the DS2786 Battery Fuel Gauge in a 2-Cell Battery Pack9/4/2007
Tools & Simulations
Software Development
Design Resources
ADI has always placed the highest emphasis on delivering products that meet the maximum levels of quality and reliability. We achieve this by incorporating quality and reliability checks in every scope of product and process design, and in the manufacturing process as well. "Zero defects" for shipped products is always our goal.
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Lead Times
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Pricing displayed is based on 1-piece. The USA list pricing shown is for budgetary use only, shown in United States dollars (FOB USA per unit), and is subject to change. International prices may vary due to local duties, taxes, fees and exchange rates.