LG M6100 Service Manual - Page 37

Charging IC ISL6299, U401

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3. TECHNICAL BRIEF 3.6 Charging IC (ISL6299, U401) CUR_MON (ABB AUX2) CHG_EN (GPIO0) VUSBIN VCHARGE Charging IC C407 NA R405 10K R406 0 R410 (1%) R408 R411 10K 39K 10K C411 1u D401 CUS02 U402 1 CRDL BAT 10 2 USB 6 IMIN 9 ICDL _PPR 3 _CHG 4 7 5 USBON _EN GND 8 11 PGND ISL6299 C412 R409 1u 100K VBAT 2V8_VEXT R403 10K CHG_STAT C413 1u CHG_EN_IO Figure 3-16. CIRCUIT FOR BATTERY CHARGING The ISL6299 is designed for a single-cell Li-ion or Li-polymer battery charging circuit that accepts both a USB port and a desktop cradle as its power source. Input Auto Selection When both input sources are present, the charger selects only one power source to charge the battery. When the CRDL input is higher than the POR threshold, CRDL is selected as the power source. Otherwise the USB input is selected. If the CRDL input voltage is below the battery voltage but the USB input voltage is higher than the battery voltage, then the USB input is used to charge the battery. The control circuit always breaks both internal power devices before switching from one power source to the other to avoid a cross conduction of both power MOSFETs. USB Charge Current When the USB port is selected as the power source, the charge current enabled by the logic input at the USBON pin. When the USBON is driven to logic LOW, the charger is disabled. When the USBON is driven to logic HIGH, the charge current is fixed at a typical value of 380mA. Thus for the USB input, the USBON pin has a similar function as the EN pin. The following table describes the USB charge control by both The USBON pin is equivalent to a logic LOW when left floating. Typically the P-channel MOSFET for the USB input has an rDS(ON) of 700mΩ at room temperature. With a 380mA charge current, the typical head room is 260mV. Thus, if the input voltage drops to a level that the voltage difference between the USB pin and the BAT pin is less than 260mV, the rDS(ON) becomes a limiting factor of the charge current; and the charger drops out the constant current regulation. - 38 -

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3. TECHNICAL BRIEF
- 38 -
3.6 Charging IC (ISL6299, U401)
The ISL6299 is designed for a single-cell Li-ion or Li-polymer battery charging circuit that accepts both a
USB port and a desktop cradle as its power source.
Input Auto Selection
When both input sources are present, the charger selects only one power source to charge the battery.
When the CRDL input is higher than the POR threshold, CRDL is selected as the power source. Otherwise
the USB input is selected. If the CRDL input voltage is below the battery voltage but the USB input voltage
is higher than the battery voltage, then the USB input is used to charge the battery. The control circuit
always breaks both internal power devices before switching from one power source to the other to avoid a
cross conduction of both power MOSFETs.
USB Charge Current
When the USB port is selected as the power source, the charge current enabled by the logic input at the
USBON pin. When the USBON is driven to logic LOW, the charger is disabled. When the USBON is driven
to logic HIGH, the charge current is fixed at a typical value of 380mA. Thus for the USB input, the USBON
pin has a similar function as the EN pin. The following table describes the USB charge control by both
The
USBON pin is equivalent to a logic LOW when left floating. Typically the P-channel MOSFET for the USB
input has an rDS(ON) of 700mΩ at room temperature. With a 380mA charge current, the typical head room
is 260mV. Thus, if the input voltage drops to a level that the voltage difference between the USB pin and the
BAT pin is less than 260mV, the rDS(ON) becomes a limiting factor of the charge current; and the charger
drops out the constant current regulation.
Charging IC
(1%)
(GPIO0)
(ABB AUX2)
VUSBIN
D401
CUS02
VCHARGE
1u
C413
10K
R405
VBAT
100K
R409
R410
10K
NA
C407
C412
1u
R406
0
USB
USBON
7
4
_CHG
_EN
5
_PPR
3
39K
R408
ISL6299
U402
BAT
10
CRDL
1
8
GND
ICDL
9
6
IMIN
PGND
11
2
10K
R411
C411
1u
2V8_VEXT
R403
10K
CHG_EN_IO
CHG_STAT
CUR_MON
CHG_EN
Figure 3-16. CIRCUIT FOR BATTERY CHARGING