LTC4075EDD Ver la hoja de datos (PDF) - Linear Technology
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LTC4075EDD Datasheet PDF : 16 Pages
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OPERATIO
LTC4075/LTC4075X
The power supply status output (P⎯ W⎯ R⎯ ) has two states: pull-
down and high impedance. The pull-down state indicates
that power is present at either DCIN or USBIN. This output
is strong enough to drive an LED. If no power is applied at
either pin, the ⎯P⎯W⎯R pin is high impedance, indicating that
the LTC4075 lacks sufficient power to charge the battery.
The pull-down state is capable of sinking up to 10mA.
The USB power status output (USBPWR) has two states:
Thermal Limiting
An internal thermal feedback loop reduces the programmed
charge current if the die temperature attempts to rise above
a preset value of approximately 105°C. This feature protects
the LTC4075 from excessive temperature and allows the
user to push the limits of the power handling capability of
a given circuit board without risk of damaging the device.
The charge current can be set according to typical (not
pull-down and high impedance. The high impedance worst-case) ambient temperature with the assurance that
state indicates that the LTC4075 is being powered from the charger will automatically reduce the current in worst-
the USBIN input. The pull-down state indicates that the case conditions. DFN power considerations are discussed
charger is either powered from DCIN or is in a UVLO further in the Applications Information section.
condition (see Table 1). The pull-down state is capable of
sinking up to 1mA.
STARTUP
BAT < 2.9V
DCIN POWER APPLIED
ONLY USB POWER APPLIED
POWER SELECTION
TRICKLE CHARGE
MODE*
1/10th FULL CURRENT
CHRG STATE: PULLDOWN
DCIN POWER
REMOVED
USBIN POWER
REMOVED OR
DCIN POWER
APPLIED
TRICKLE CHARGE
MODE*
1/10th FULL CURRENT
CHRG STATE: PULLDOWN
BAT < 2.9V
BAT > 2.9V
2.9V < BAT
CHARGE
MODE
FULL CURRENT
CHRG STATE: PULLDOWN
IBAT < ITERMINATE
IN VOLTAGE MODE
BAT > 2.9V
CHARGE
MODE
FULL CURRENT
CHRG STATE: PULLDOWN
2.9V < BAT
IBAT < ITERMINATE
IN VOLTAGE MODE
BAT < 4.1V
STANDBY
MODE
NO CHARGE CURRENT
CHRG STATE: Hi-Z
STANDBY
MODE
NO CHARGE CURRENT
CHRG STATE: Hi-Z
BAT < 4.1V
ENABLE
DRIVEN LOW
*LTC4075 ONLY
SHUTDOWN
MODE
IDCIN DROPS TO 20µA
CHRG STATE: Hi-Z
ENABLE
DRIVEN HIGH
DCIN POWER
REMOVED
ENABLE
DRIVEN LOW
USBIN POWER
REMOVED OR
DCIN POWER
APPLIED
SHUTDOWN
MODE
IUSBIN DROPS TO 18µA
CHRG STATE: Hi-Z
ENABLE
DRIVEN HIGH
4075 F01
Figure 1. LTC4075 State Diagram of a Charge Cycle
4075Xf
11
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