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
capacitywww.DataSheet4U.com 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.
3G Multimedia Wireless Handsets
Digital Still Cameras
Digital Audio (MP3) Players
TYPICAL OPERATING CIRCUIT
Standalone OCV-Based Fuel Gauge
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:
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
±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
Low Power Consumption:
Active Current: 50μA typ, 80μA max
Sleep Current: 1μA typ, 3μA max
-20ºC to +70ºC
-20ºC to +70ºC
+ Denotes lead-free package.
Commands, Registers, and Modes are capitalized for clarity.
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3mm x 3mm TDFN-10