RT9519A RICHTEK [Richtek Technology Corporation], RT9519A Datasheet - Page 11

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

DS9519A-02 April 2011
Battery Pack Temperature Monitoring
The battery pack temperature monitoring function can be
realized by connecting the TS pin to an external Negative
Temperature Coefficient (NTC) thermistor to prevent over
temperature condition. Charging is suspended when the
voltage at the TS pin is out of normal operating range. The
internal timer is then paused, but the value is maintained.
When the TS pin voltage returns back to normal operating
range, charging will resume and the safe charge timer will
continue to count down from the point where it was
suspended. Note that although charging is suspended due
to the battery pack temperature fault, the CHG pin will
continue to remain low and indicate charging.
Too Cold Temperature
R
Too Hot Temperature
R
Charge State Indicator
R
R
COLD
HOT
COLD
HOT
IC Disabled or no Valid
R2 + R
R2 + R
Charging Suspended by
Safety Timers Expired
= R
Recharging after
R
= R
+ R1 +R2
NTC
Charging Done
Charge State
+ R1 + R2
Thermal Loop
Input Power
Termination
NTC
R1
R2
COLD
NTC
HOT
Charging
VP
TS
= 0.375
= 0.6
VP
Figure 1
0.375 x VP
0.6 x VP
(for first charge cycle)
-
+
-
+
High Impedance
CHG Output
2Hz Flash
Low
Too Cold
Too Hot
(1)
(2)
Charge Enable
When EN is low, the charger turns on. When EN is high,
the charger turns off. EN is pulled low for initial condition.
VIN input Current Limit
Suspend Mode
Set USUS = H, and the charge will enter Suspend Mode.
In the Suspend Mode, CHG is in high impedance and
I
Power Switch
For the RT9519A, there are three power scenarios:
(1)When a battery and an external power supply (USB or
adapter) are connected simultaneously :
If the system load requirements exceed that of the input
current limit, the battery will be used to supplement the
current to the load. However, if the system load
requirements are less than that of the input current limit,
the excess power from the external power supply will be
used to charge the battery.
(2)When only the battery is connected to the system :
The battery provides the power to the system.
(3)When only an external power supply is connected to
the system :
If R2 < 0
From (1), (2)
R1 =
R2 = 0.6 R1 R
From (3)
R1 =
R
USUS(MAX)
COLD
R
COLD
ISETL
R
R
COLD
COLD
H
H
+ R1
0.6
L
×
< 300μA.
0.9
−
= 0.6
−
−
R
R
HOT
COLD
HOT
ISETU
H
X
L
VIN Input Current
RT9519A
www.richtek.com
475mA
95mA
Limit
1.5A
(3)
11