LTC4078EDD-TRPBF 查看數據表（PDF） - Linear Technology

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LTC4078EDD-TRPBF

Dual Input Li-Ion Battery Charger with Overvoltage Protection

Linear Technology 

LTC4078/LTC4078X

OPERATION

This output is strong enough to drive an LED. If no valid

voltage is applied at either pin, the PWR pin is high im-

pedance, indicating that the LTC4078/LTC4078X lack valid

input voltage (see Table 1) to charge the battery.

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 120°C. This feature protects

the LTC4078/LTC4078X from excessive temperature and

allows the user to push the limits of the power handling

capability of a given circuit board without risk of damag-

ing the device. The charge current can be set according

to typical (not worst-case) ambient temperature with the

assurance that the charger will automatically reduce the

current in worst case conditions. DFN package power

considerations are discussed further in the Applications

Information section.

DCIN POWER REMOVED

ENABLE = LOW

NO POWER

USB POWER REMOVED

POWER APPLIED

ENABLE = HIGH

6V > DCIN > 4.15V

NO

AND DCIN > BAT

YES

NO

BATDET < 1.75V

YES

FULL CURRENT (BAT > 2.9V)

1/10TH FULL CURRENT

(BAT < 2.9V)*

CHRG STATE: PULLDOWN

IBAT < ITERMINATE

IN VOLTAGE MODE

BAT < 4.075V

STANDBY MODE

(DCIN)

NO CHARGE CURRENT

CHRG STATE: Hi-Z

YES

DCIN > 4.15V

AND DCIN > BAT

NO

NO

6V > USBIN > 3.95V

AND USBIN > BAT

YES

NO

BATDET < 1.75V

YES

FULL CURRENT (BAT > 2.9V)

1/10TH FULL CURRENT

(BAT < 2.9V)*

CHRG STATE: PULLDOWN

IBAT < ITERMINATE

IN VOLTAGE MODE

STANDBY MODE

(USBIN)

NO CHARGE CURRENT

CHRG STATE: Hi-Z

BAT < 4.075V

*LTC4078 ONLY

SHUTDOWN MODE

(DCIN)

CHRG STATE: Hi-Z

SHUTDOWN MODE

(USBIN)

CHRG STATE: Hi-Z

4078X F01

Figure 1. LTC4078 State Diagram of a Charge Cycle

4078xfb

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