RT9519A RICHTEK [Richtek Technology Corporation], RT9519A Datasheet - Page 12

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

RT9519A
The external power supply provides the power to the
system.
Input DPM Mode
For the RT9519A, the input voltage is monitored when
the USB100 or USB500 is selected. If the input voltage is
lower than V
stop the input voltage from dropping any further. This can
prevent the IC from damaging improperly configured or
inadequately designed USB sources.
APPM Mode
Once the sum of the charging and system load currents
becomes higher than the maximum input current limit,
the SYS pin voltage will be reduced. When the SYS pin
voltage is reduced to the V
automatically operate in APPM mode. In this mode, the
charging current is reduced while the SYS current is
increased to maintain system output. In APPM mode,
the battery termination function is disabled.
Battery Supplement Mode Short Circuit Protect
In APPM mode, the SYS voltage will continue to drop if
the charge current is zero and the system load increases
beyond the input current limit. When the SYS voltage
decreases below the battery voltage, the battery will kick
in to supplement the system load until the SYS voltage
rises above the battery voltage.
Charging Profile
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12
DPM
, the input current limit will be reduced to
I
CHG_PRE
Battery Voltage
Charging Current
V
PRECH
APPM
= 10% x I
, the RT9519A will
CHG_FAST
I
If
TERM
Figure 2
ISETL = H, ISETU = H
ISETL = L, ISETU = X
I
TERMI
If ISETL = H, ISETU = L
I
TERMI
4.16 to 4.2 to 4.23V
While in supplement mode, there is no battery supplement
current regulation. However, a built in short circuit
protection feature is available to prevent any abnormal
current situations. While the battery is supplementing the
load, if the difference between the battery and SYS voltage
becomes more than the short circuit threshold voltage,
SYS will be disabled. After a short circuit recovery time,
t
mode, the battery termination function is disabled. Note
that for the battery supply mode exit condition, V
V
Thermal Regulation and Thermal Shutdown
The RT9519A provides a thermal regulation loop function
to monitor the device temperature. If the die temperature
rises above the regulation temperature, T
current will automatically be reduced to lower the die
temperature. However, in certain circumstances (such as
high VIN, heavy system load, etc.) even with the thermal
loop in place, the die temperature may still continue to
increase. In this case, if the temperature rises above the
thermal shutdown threshold, T
between VIN and SYS will be turned off. The switch
between the battery and SYS will remain on, however, to
allow continuous battery power to the load. Once the die
temperature decreases by
between VIN and SYS will be turned on again and the
device returns to normal thermal regulation.
SHORT_R
= 10% x I
SYS
-40 to 85
= 3.3% x I
< 0V.
I
TERM2
, the counter will be restarted. In supplement
CHG_FAST
°
C
CHG_FAST
V
RECH
Time
Δ
T
SD
DS9519A-02 April 2011
SD
, the internal switch
,
the internal switch
REG
, the charge
BAT
−