DS2786.pdf

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