ds2761 Maxim Integrated Products, Inc., ds2761 Datasheet - Page 7

• Manufacturer Part Number: ds2761
• Description: Ds2761 High-precision Li+ Battery Monitor
• Manufacturer: Maxim Integrated Products, Inc.

DISCHARGE
charge FET back on (unless another protection condition prevents it). Discharging remains enabled
during overvoltage, and the DS2761 re-enables the charge FET before V
-80mA (V
Undervoltage. If the voltage of the cell drops below undervoltage threshold V
undervoltage delay t
protection register, and enters sleep mode. The DS2761 provides a current-limited recovery charge path
from PLS to V
Overcurrent, Charge Direction. The voltage difference between the IS1 pin and the IS2 pin (V
V
V
COC flag in the protection register. The charge current path is not re-established until the voltage on the
PLS pin drops below V
PLS down in order to detect the removal of the offending charge current source.
Overcurrent, Discharge Direction. If V
shuts off the external discharge FET and sets the DOC flag in the protection register. The discharge
current path is not re-established until the voltage on PLS rises above V
test current of value I
low-impedance load.
Short Circuit. If the voltage on the SNS pin with respect to V
period longer than short-circuit delay t
DOC flag in the protection register. The discharge current path is not re-established until the voltage on
PLS rises above V
PLS up in order to detect the removal of the short circuit.
Figure 3. Li+ PROTECTION CIRCUITRY EXAMPLE WAVEFORMS
CHARGE
IS2
OC
SLEEP
) is the filtered voltage drop across the current-sense resistor. If V
MODE
for a period longer than overcurrent delay t
V
CELL
(1) To allow the device to react quickly to short circuits, detection occurs on the SNS pin rather than on the
CC
DC
V
IS
filtered IS1 and IS2 pins. The actual short-circuit detect condition is V
IS
≤ -2mV) or less is detected.
DD
t
OVD
to gently charge severely depleted cells during sleep mode.
DD
UVD
TST
- V
DD
t
SCD
, the DS2761 shuts off the charge and discharge FETs, sets the UV flag in the
from V
TP
- V
. The DS2761 provides a test current of value I
TP
(1)
. The DS2761 provides a test current of value I
DD
to PLS to pull PLS up in order to detect the removal of the offending
t
OVD
SCD
IS
, the DS2761 shuts off the external discharge FET and sets the
is less than -V
t
OCD
OCD
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, the DS2761 shuts off both external FETs and sets the
t
OCD
OC
for a period longer than t
SS
exceeds short-circuit threshold V
SNS
> V
DD
IN
IS
SC
< V
t
exceeds overcurrent threshold
- V
UVD
.
TST
TST
TP
UV
CE
from V
. The DS2761 provides a
if a discharge current of
for a period longer than
from PLS to V
DD
OCD
-V
V
V
V
V
V
-V
V
V
V
ACTIVE
INACTIVE
0
to PLS to pull
SS
OV
CE
UV
OC
PLS
SS
DD
, the DS2761
OC
SC
IS
SS
= V
SC
DS2761
to pull
for a
IS1
-