ME4057

V01

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constant current mode, the charge current is set by RPROG. When the battery approaches the regulation voltage 4.2V,

the charge current begins to decrease as the ME4057 enters the constant-voltage mode. When the current drops to

charge termination threshold, the charge cycle is terminated, and

pin assumes a high impedance state to

indicate that the charge cycle is terminated and

pin is pulled low. The charge termination threshold is 10% of

the current in constant current mode. To restart the charge cycle, remove the input voltage and reapply it, or

momentarily force CE pin to 0V. The charge cycle can also be automatically restarted if the BAT pin voltage falls

below the recharge threshold. The on-chip reference voltage, error amplifier and the resistor divider provide

regulation voltage with 1% accuracy which can meet the requirement of lithium-ion and lithium polymer batteries.

When the input voltage is not present, or input voltage is below VBAT, the charger goes into a sleep mode, dropping

battery drain current to less than 3

μA. This greatly reduces the current drain on the battery and increases the

standby time. The charger can be shutdown by forcing the CE pin to GND.

The charging profile is shown in the following figure:

Programming charge current

The charge current is programmed using a single resistor from the PROG pin to ground. The program resistor

and the charge current are calculated using the following equations.:

In application, according the charge current to determine RPROG ,the relation between RPROG and charge current

can reference the following chart: