NE57611BDH Philipss, NE57611BDH Datasheet - Page 7

• Manufacturer Part Number: NE57611BDH
• Description: Single cell Li-ion battery charger
• Manufacturer: Philipss

Philips Semiconductors
NE57611 CHARACTERISTICS
The NE57611 is a precise linear-mode battery charger with a cell
undervoltage detector. It contains the minimum circuitry needed to
safely charge a lithium-ion or lithium-polymer cell. This makes it
good for very compact, portable applications.
The charging process is permitted to start when the DC input
voltage is greater than V
overvoltage point (V
voltage is continuously monitored by the charge controller and will
fall into one of three voltage ranges:
1. If the cell has been severely discharged or allowed to sit on the
2. If the cell has only been partially discharged then the voltage will
3. If the cell has inadvertently been overcharged and is being
2003 Oct 15
Single cell Li-ion battery charger
shelf for a long period of time, the cell will be in the undervoltage
range, which is less than 2.3 V.
fall into the normal range.
reconnected to the charger, the cell is in the overcharged range.
OV
), and the ON/OFF pin is LOW. The cell
IN(min)
ON/OFF
, the battery voltage is less than the
1
8
V
CC
1.2 V
7
DRV
Figure 5. Functional diagram.
3
LV
COMPARATOR
CURRENT
CHARGE
2
LVEN
7
UNVERVOLTAGE
COMPARATOR
COMPARATOR
TERMINATION
5
CHARGE
CS
The charger circuit then responds in the following manner if the
battery pack voltage is:
1. <2.15 V (V
2. 2.15 V < V
3. V
V
CELL
which enables an external precharge circuit. The precharge
circuit then charges the undervoltage cell with a very low current
(1 – 5 mA) to bring the cell voltage up to a voltage greater than
V
overdischarge.
placed into the battery pack. During this time, the charge
controller charges the cell with a constant current as set by the
value of R
threshold, the charging current begins to decrease until the
cell voltage reaches the overvoltage termination voltage. This
portion of the charge process is called constant voltage charge.
and the charging is discontinued. Some small current will
continue to flow into the cell to replace any self-discharge losses
within the cell, but will not overcharge the cell.
LV
CELL
. This may take a long time depending upon the depth of the
GND
4
> 4.35 V (V
CS
LV
CELL
. When the cell voltage approaches the overvoltage
): The LV pin (open collector) assumes a LOW state
< 4.35 V (V
OV
V
6
CELL
): The charge current tapers down to zero
V
UNVERVOLTAGE
DETECTOR
CC
SL01664
OV
): The normal charge current is
NE57611
Product data