DS2760

8 of 25

outputs.

(Protection Register bit DE = 0) or (Sleep Mode)

(Sleep Mode)

CURRENT MEASUREMENT

In the Active Mode of operation, the DS2760 continually measures the current flow into and out of the

battery by measuring the voltage drop across a current sense resistor. The DS2760 is available in two

configurations: (1) internal 25 m

Ω current sense resistor, and (2) external user-selectable sense resistor. In

battery (discharging). Note than when an external sense resistor is used, one end of the resistor must be

wired directly to VSS (the negative terminal of the cell) for proper operation of the current measurement

circuitry.

two’s-complement format. Currents outside the range of the register are reported at the limit of the range.

The format of the Current Register is shown in Figure 4.

For the internal sense resistor configuration, the DS2760 maintains the Current Register in units of Amps,

with a resolution of 0.625 mA and full scale range of no less than

±1.8A (see Note 7 on I

details).

The DS2760 automatically compensates for internal sense resistor process variations and

temperature effects when reporting current.

Register, with a resolution of 15.625

µV and a full scale range of ±64 mV.

CURRENT REGISTER FORMAT – Figure 4

MSB—Address 0E

LSB—Address 0F

S2

11

2

10

2

9

2

8

2

7

2

6

2

5

2

4

2

3

2

2

2

1

2

0

XX

X

MSb

LSb

MSb

LSb

Units: 0.625 mA for internal sense resistor

15.625

µV for external sense resistor

CURRENT ACCUMULATOR

The Current Accumulator facilitates remaining capacity estimation by tracking the net current flow into

and out of the battery. Current flow into the battery increments the Current Accumulator while current

flow out of the battery decrements it.

Data is maintained in the Current Accumulator in two’s-

complement format. The format of the Current Accumulator is shown in Figure 5.