ds2775 Maxim Integrated Products, Inc., ds2775 Datasheet - Page 13

• Manufacturer Part Number: ds2775
• Description: 2-cell, Stand-alone, Li+ Fuel-gauge Ic With Protector And Optional Sha-1 Authentication
• Manufacturer: Maxim Integrated Products, Inc.

If the average of the voltages on (V
(V
V
the DS2775–DS2778 shut off the charge and discharge
FETs and set the UV flag in the Protection register. If
UVEN is set, the DS2775–DS2778 also enter sleep
mode. When a charger is detected and V
the DS2775–DS2778 provide a current-limited recovery
charge path (I
severely depleted cells. The recovery charge path is
enabled when 0 ≤ [(V
V
(V
Charge current develops a negative voltage on V
with respect to V
overcurrent threshold, V
overcurrent delay, t
both external FETs and set the COC flag in the
Protection register. The charge current path is not re-
established until the voltage on the PLS pin drops
below (V
current of value I
in order to detect the removal of the offending charge
current source.
Discharge current develops a positive voltage on V
with respect to V
overcurrent threshold, V
t
charge FET and set the DOC flag in the Protection reg-
ister. The discharge current path is not reestablished
Figure 4. Voltage Register Format
OCD
UV
CE
IN1
IN1
, for a period longer than undervoltage delay, t
. The FETs remain off until (V
Overcurrent, Discharge Direction (DOC)
MSb
“S”: SIGN BITS(S), “X”: RESERVED
, the DS2775–DS2778 shut off the external dis-
- V
S
- V
Protector and Optional SHA-1 Authentication
Overcurrent, Charge Direction (COC)
SS
DD
SS
) exceed V
) drops below the undervoltage threshold,
2-Cell, Stand-Alone, Li+ Fuel-Gauge IC with
2
- V
9
MSB - ADDRESS 1Ch, V
MSB - ADDRESS 0Ch, V
RC
TP
). The DS2775–DS2778 provide a test
PPD
) from PLS to V
______________________________________________________________________________________
SS
SS
2
8
OCD
. If V
. If V
UV
from PLS to V
IN2
.
, the DS2775–DS2778 shut off
COC
DOC
2
SNS
SNS
7
- V
, for a period longer than
, for a period longer than
IN1
is less than the charge
exceeds the discharge
2
Undervoltage (UV)
6
) and (V
DD
IN2
IN1
SS
2
to gently charge
IN2
, pulling PLS up,
- V
- V
5
IN2
IN1
SS
IN1
- V
PLS
2
- V
4
- V
IN1
> V
IN1
SS
) and
LSb
2
UVD
) or
)] <
SNS
SNS
3
IN2
,
,
until the voltage on PLS rises above (V
DS2775–DS2778 provide a test current of value I
from V
removal of the offending low-impedance load.
If V
period longer than short-circuit delay, t
DS2775–DS2778 shut off the external discharge FET
and set the DOC flag in the Protection register. The
discharge current path is not reestablished until the
voltage on PLS rises above (V
DS2778 provide a test current of value I
to PLS, pulling PLS up, in order to detect the removal
of the short circuit.
All the protection conditions described are logic
ANDed to affect the CC and DC outputs.
Cell voltages are measured every 440ms. The lowest
potential cell, V
The highest potential cell, V
respect to V
range of -5V to +4.9951V and a resolution of 4.8828mV
and placed in the Result register in two’s complement
form. Voltages above the maximum register value are
reported as 7FE0h.
(overcurrent, charge direction) AND (Protection register
DC = (undervoltage) AND (overcurrent, either direction)
MSb
UNITS: 4.883mV
2
SNS
2
and (short circuit) AND (Protection register bit
CC = (overvoltage) AND (undervoltage) AND
DD
exceeds short-circuit threshold, V
2
to PLS, pulling PLS up, in order to detect the
1
LSB - ADDRESS 1Dh, V
LSB - ADDRESS 0Dh, V
IN1
. Battery voltages are measured with a
IN1
2
0
Voltage Measurements
, is measured with respect to V
bit CE = 0)
X
DE = 0)
X
DD
IN2
Short Circuit (SC)
IN2
IN1
- V
, is measured with
X
- V
- V
TP
IN1
SS
). The DS2775–
DD
TST
X
- V
SCD
from V
SC
TP
LSb
X
, for a
). The
, the
TST
SS
DD
13
.