RT9519A Просмотр технического описания (PDF) - Richtek Technology

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RT9519A

Linear Single Cell Li-lon Battery Charger with Auto Power Path Management

Richtek Technology 

RT9519A

Charge State Indicator

Charge State

Charging

Charging Suspended by

Thermal Loop

Safety Timers Expired

Charging Done

Recharging after

Termination

IC Disabled or no Valid

Input Power

CHG Output

Low

(for first charge cycle)

2Hz Flash

High Impedance

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.

VP

VP

R1

R2

RNTC

0.6 x VP -

TS

+

-

+

0.375 x VP

Too Cold

Too Hot

Figure 1

Too Cold Temperature

RCOLD = RNTC

Too Hot Temperature

RHOT = RNTC

R2 + RCOLD = 0.6

(1)

RCOLD + R1 + R2

R2 + RHOT = 0.375

(2)

RHOT + R1 +R2

DS9519A-02 April 2011

From (1), (2)

R1 = RCOLD − RHOT

0.9

R2 = 0.6 ×R1− RHOT

If R2 < 0

RCOLD = 0.6

(3)

RCOLD + R1

From (3)

R1

=

RCOLD

0.6

− RCOLD

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

ISETL

ISETU

H

L

H

H

L

X

VIN Input Current

Limit

95mA

475mA

1.5A

Suspend Mode

Set USUS = H, and the charge will enter Suspend Mode.

In the Suspend Mode, CHG is in high impedance and

IUSUS(MAX) < 300μA.

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 :

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