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.
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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.
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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 I
2
C 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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APPLICATIONS
3G Multimedia Wireless Handsets
Digital Still Cameras
Digital Audio (MP3) Players