Datasheet

DS2786 Stand-Alone OCV-Based Fuel Gauge
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POWER MODES
The DS2786 operates in one of two power modes: Active and Sleep. While in Active mode, the DS2786 operates
as a high-precision battery monitor with temperature, voltage, auxiliary inputs, current, and accumulated current
measurements acquired continuously and the resulting values updated in the Measurement Registers. In Sleep
mode, the DS2786 operates in a low-power mode with no measurement activity. Read and write access is allowed
to all registers in either mode.
The DS2786 operating mode transitions from Sleep to Active when:
( SCL > V
IH
) OR ( SDA > V
IH
)
The DS2786 operating mode transitions from Active to Sleep when:
SMOD = 1 AND [ ( SCL < V
IL
) AND ( SDA < V
IL
) ] for t
SLEEP
CAUTION: If SMOD = 1, a pullup resistor is required on SCL and SDA in order to ensure that the DS2786
transitions from Sleep to Active mode when the battery is charged. If the bus is not pulled up, the DS2786 remains
in Sleep and cannot accumulate the charge current. This caution statement applies particularly to a battery that is
charged on a stand-alone charger.
PARAMETER MEASUREMENT
The DS2786 uses a Sigma Delta A/D converter to make measurements. The measurement sequence shown in
Figure 4 repeats continuously while the DS2786 is in Active mode. The V
OUT
pin is activated t
PRE
before the AIN0
and AIN1 conversion to allow for the V
OUT
output voltage to settle. The DS2786 can be configured to measure
temperature using its on-chip sensor instead of the AIN1 input. When the internal temperature measurement uses
the AIN1 conversion timeslot, V
OUT
is not activated. A full sequence of voltage measurements nominally takes
1760ms to complete.
Figure 4. Measurement Sequence