DS2788 MAXIM [Maxim Integrated Products], DS2788 Datasheet - Page 8

• Manufacturer Part Number: DS2788
• Description: Stand-Alone Fuel-Gauge IC with LED Display Drivers
• Manufacturer: MAXIM [Maxim Integrated Products]

The DS2788 uses an integrated temperature sensor to
measure battery temperature with a resolution of
0.125°C. Temperature measurements are updated
every 440ms and placed in the Temperature (TEMP)
register in two’s complement form. Figure 4 shows the
format of the Temperature register.
In the ACTIVE mode of operation, the DS2788 continu-
ally measures the current flow into and out of the bat-
tery by measuring the voltage drop across a low-value
current-sense resistor, R
Stand-Alone Fuel-Gauge IC with
LED Display Drivers
Figure 4. Temperature Register Format
Figure 5. Current Register Format
8
CURRENT
MSb
“S”: SIGN BIT(S)
TEMP
MSb
“S”: SIGN BIT(S), “X”: RESERVED
_______________________________________________________________________________________
S
S
2
Temperature Measurement
2
14
9
MSB—ADDRESS 0Eh
MSB—ADDRESS 0Ah
2
2
13
8
Current Measurement
V
1.5625μV
SS
2
2
SNS
12
- V
7
SNS
. The voltage-sense range
2
2
11
6
2
2
10
78.13μA
5
20m
CURRENT RESOLUTION (1 LSB)
2
2
9
4
LSb
LSb
2
2
8
3
104.2μA
15m
between SNS and V
converts peak signal amplitudes up to 102.4mV as long
as the continuous signal level (average over the con-
version cycle period) does not exceed ±51.2mV. The
ADC samples the input differentially at 18.6kHz and
updates the Current (CURRENT) register at the com-
pletion of each conversion cycle.
The Current register is updated every 3.515s with the
current conversion result in two’s complement form.
Charge currents above the maximum register value are
reported at the maximum value (7FFFh = +51.2mV).
Discharge currents below the minimum register value
are reported at the minimum value (8000h = -51.2mV).
MSb
MSb
2
R
2
7
2
SNS
2
156.3μA
2
6
1
10m
LSB—ADDRESS 0Fh
LSB—ADDRESS 0Bh
2
2
5
0
SS
2
X
4
is ±51.2mV. The input linearly
312.5μA
5m
2
X
3
UNITS: 1.5625μV/R
2
X
2
UNITS: 0.125°C
READ ONLY
READ ONLY
2
X
1
LSb
LSb
SNS
2
X
0