RT9519A RICHTEK [Richtek Technology Corporation], RT9519A Datasheet - Page 10

• Manufacturer Part Number: RT9519A
• Description: Linear Single Cell Li-lon Battery Charger with Auto Power Path Management
• Manufacturer: RICHTEK [Richtek Technology Corporation]

RT9519A
Applications Information
The RT9519A is a fully integrated single-cell Li-ion battery
charger ideal for portable applications. The internal thermal
feedback circuitry regulates the die temperature to optimize
the charge rate for all ambient temperatures. Other features
include under voltage protection and over voltage
protection.
Pre-charge Mode
When the output voltage is lower than 2.8V, the charging
current will be reduce to a fast-charge current ratio set by
R
Fast-charge Mode
When the output voltage is higher than 3V, the charging
current will be equal to the fast-charge current set by
R
Constant Voltage Mode
When the output voltage is near 4.2V, and the charging
current fall below the termination current, after a deglitch
time check of 25ms, the charger will become disabled
and CHG will go from L to H.
Re-charge Mode
When the chip is in charge termination mode, the charging
current will gradually go down to zero. However, once the
voltage of the battery drops to below 4.1V, there will be a
deglitch time of 100ms and then the charging current will
resume again.
Charging Current Decision
The charge current can be set according to the following
equations :
Time Fault
During the fast charge phase, several events may increase
the charging time.
www.richtek.com
10
If I
I
If I
I
I
CHG_FAST
CHG_FAST
CHG_PRE
ISETA
ISETA
SET
SET
.
to protect the battery life time.
= H (for I
= L (for I
= 10% I
=
=
R
R
V
V
ISETA
ISETA
ISETA
ISETA
CHG2
CHG1
×
CHG_FAST
)
)
×
×
150
300
For example the system load current may have activated
the APPM loop which reduces the available charging
current. the device has entered thermal regulation because
the IC junction temperature has exceeded T
During each of these events, if 3V < V
internal charging time is slowed down proportionately to
the reduction in charging current. However, once the
duration exceed the fault time, the CHG output will flash
at approximately 2Hz to indicate a fault condition and the
charge current will be reduced to about 1mA.
Time fault release methods :
(1) Re-plug power
(2) Toggle EN
(3) Enter/exit suspend mode
(4) Remove Battery
(5) OVP
Note that the fast charge fault time is independent of the
charge current.
Power Good
VIN Power Good (
t
t
t
t
t
t
FCHG_true
FCHG_true
FCHG
FCHG
PCHG
PCHG
V
V
UVLO
BAT
: original timer in fast charger
= 14400 sec (
=
: timer in pre-charge
+ V
t
FCHG
< V
V
Input State
V
= t
: modified timer in fast
8
IN
OS_H
IN
FCHG
IN
< V
> V
< V
PGOOD
UVLO
< V
OVP
×
BAT
×
V
IN
ISETA
C
2V
+ V
< V
TIMER
1 F
μ
= L)
OS_H
OVP
)
DS9519A-02 April 2011
PGOOD Output
High Impedance
High Impedance
High Impedance
Low Impedance
BAT
REG
< 4.1V, the
.