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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
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.
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Data Sheet
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An evaluation kit 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
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Applications/Uses
- 3G Multimedia Wireless Handsets
- Digital Audio (MP3) Players
- Digital Still Cameras
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Key Specifications:
| Battery Protectors, Selectors and Monitors |
| Part Number |
Functions |
Battery Type |
Interface |
User Data Storage
(Bytes) |
Parameters Measured |
VSUPPLY
(V) |
VSUPPLY
(V) |
Package/Pins |
Smallest Available Pckg.
(mm2) |
Oper. Temp.
(°C) |
Budgetary Price |
| min |
max |
max w/pins |
See Notes |
| DS2786 |
Fuel Gauge |
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2-Wire |
32 EEPROM |
| Current | | Temperature | | Voltage |
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2.5 |
5.5 |
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9.6 |
-40 to +85 |
$1.53 @1k |
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See All Battery Protectors, Selectors and Monitors (34)
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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 prices and delivery, please see the price and availability page or contact an authorized distributor.
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Diagram
Typical Operating Circuit
More Information
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Information Index
Document Ref.: 19-4637
Rev 8;
2009-06-22
This page last modified: 2009-09-01
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