LM3621M/NOPB National Semiconductor, LM3621M/NOPB Datasheet - Page 13

• Manufacturer Part Number: LM3621M/NOPB
• Description: IC CTRLR LI-ION BAT CHRG 16-SOIC
• Manufacturer: National Semiconductor

Specifications of LM3621M/NOPB

• Function: Charge Management
• Battery Type: Lithium-Ion (Li-Ion)
• Operating Temperature: 0°C ~ 70°C
• Mounting Type: Surface Mount
• Package / Case: 16-SOIC (0.154", 3.90mm Width)
• Lead Free Status / RoHS Status: Lead free / RoHS Compliant
• Other names: *LM3621M; *LM3621M/NOPB; LM3621M

Application Information
FAULT PROTECTION
LM3621 provides redundant fault protection for a Li-Ion bat-
tery pack. If the charger’s control loop is accidentally
opened, the regulation voltage will begin to increase beyond
the level that are safe for the battery. In order to protect the
battery from a fault condition, PFD goes low to turn off the
series pass FET whenever the voltage across the battery
exceeds the over voltage detection threshold (V
whenever V
both of the LED drivers to pulse at 0.8 Hz. Enable must go
low to cause the LM3621 to transition from the Fault State to
Standby mode.
LOW CURRENT DRAIN OF BATTERY
If power is inadvertently removed from the battery charger,
the voltage at the V
as the V
of the LM3621 from the V
(typical) of leakage current will be drawn from the battery.
SS
pin. An internal switch will disconnect the circuitry
CSR
exceeds 1V. A fault condition also causes
DD
pin will collapse to the same potential
BAT
+ pin so that no more than 1µA
FIGURE 6. Adjusting V
(Continued)
BAT
FIGURE 5. Battery Refresh
-Det) or
CSR
by applying V
13
ADJUSTABLE CHARGE CURRENT
The current sense resistor (Rcs) converts the charging cur-
rent to a voltage level, V
source (V
Fast Charge current regulation. Simultaneously the regula-
tion level for Boost mode, Hi-Z Charge mode, End-of-Charge
threshold and over current detect threshold will also be
adjusted accordingly. The voltage at I
within the range of 1V ≥ V
of V
Fast Charge Mode, V
Hi-Z Mode, V
Boost Mode, V
Over Current Threshold, V
End-Of-Charge, V
CSR
to V
EXT
EXT
10010716
ISET
) to the I
CSR
to I
CSR
are:
= 0.083·V
SET
CSR
= 0.48·V
SET
CSR
pin
= 0.07·V
10010705
pin will adjust the value of V
CSR
ISET
= 0.933·V
CSR
ISET
ISET
. Applying an external voltage
≥ 0.1V. The transfer functions
ISET
= 0.36·V
+0.65
ISET
ISET
SET
+0.79
pin should be
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CSR
for