APL3207 View Datasheet(PDF) - Anpec Electronics
Part Name
Description
MFG CO.
'APL3207' PDF : 19 Pages View PDF
APL3207
Function Description
Charge Cycle
Charge Termination Detection and Recharge
When the APL3207 is powered with a battery connected,
the IC firstly detects if the cell voltage is ready for full
charge current. If the battery voltage is below pre-charge
threshold (2.9V typ.), the device supplies 1/10 the pro-
Charging is terminated when I falls to 10% of the full
CHG
charge current set by RSET and the charger is in voltage
mode (VBATT is nearly 4.2V). The charge termination is
detected by monitoring the ISET pin. When the ISET pin
grammed charge current. On the contrary, when the bat- voltage falls below 0.1V and takes longer than TTERM (1ms,
tery voltage is over the pre-charge threshold, the device typical), charging is terminated. The STAT output keeps
supplies the full charge current, as programmed by RSET high state when the charger operates in standby mode.
from the ISET pin to the GND. When the battery voltage After charge termination, the battery voltage is monitored
approaches the 4.2V termination voltage, the device en- by the APL3207 continuously. If the battery voltage drops
ters constant-voltage mode and the full charge current below 4.05V and takes longer than T
(2ms, typical),
RECHARGE
gradually decreases until the charge current drops to the a new charge cycle starts to recharge the battery.
termination current threshold, which is equal to 1/10 full
charge current, and the IC stops charging (See Figure 1).
Manual Shutdown
The ISET pin provides two functions: connecting the re-
ICHG
1C
ICHG
VBATT
VBATT
sistor R from the ISET pin to the GND to set the full
SET
charge current; and disconnecting the R from the GND
SET
4.2V
4.05V
to shut down the charging device. Once the RSET is
disconnected, an internal 2.5µA current will pull the ISET
pin high. When the ISET pin voltage reaches the 1.21V
shutdown threshold voltage, the charging device enters
3.0V shutdown mode. In shutdown mode, the charging stops,
the VIN supply current drops to 25µA and the battery drain
0.1C
Pre- Full Charge
Constant
charge
Voltage Mode
Figure 1. Typical Charging Profile
Full Charge Current Setting
current is below 1µA. Reconnecting RSET to the GND en-
ables the charger to operate normally. The STAT output is
in high state when the charger is in shutdown mode.
Thermal Regulation
The APL3207 is thermally regulated to keep the junction
The full charge current is programmed by connecting a temperature at 120°C. When the junction temperature
resistor from the the ISET pin to the ground. The full charge reaches 120°C, the charger does not shut down but re-
current is 1000 times of the current flowing out of the duces charge current to keep the junction temperature at
ISET pin and can be calculated by the following equation: 120°C. This feature protects the APL3207 from exces-
ICHG
=
KSET × VSET
RSET
where:
VSET is ISET regulation voltage (1V, typcial).
K is the charge current set factor (1000, typical).
SET
sive temperature and allows the charger to operate with
maximum power dissipation by reducing the charge cur-
rent and optimizes the board design for compact size and
typical thermal conditions.
Charge Status Output (STAT)
The charge current set factor and the ISET regulation volt-
age are shown in the Electrical Characteristics. The ISET
regulation voltage is reduced by the thermal regulation
function.
The STAT is an open-drain output. When the charger is in
charge mode, the STAT output is in pull-low state. Until
the charge current drops to the termination current
threshold, the charging stops, and the STAT output is in
high impedance state.
Copyright © ANPEC Electronics Corp.
12
Rev. A.3 - Sep., 2012
www.anpec.com.tw
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