AS3658 datasheet(54/158 Pages) AMSCO

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AS3658

Data Sheet Confidential - Detail ed Descri ption-Power Management Functions

Battery Detection and Restart of Charging:

In EOC state, If the battery voltage drops below VCHRES and the bit AutoResume is set, the battery detection is

started. The battery switch will be switched into current source mode and VSUPPLY will be regulated to Vchlimit (all

charger). The AS3658 measured the battery current with the fuel gauge in this mode. If there is no current, the AS3658

is kept in this state and the bit NoBat is set. Otherwise the bit NoBat is cleared and the charger and the AS3658

continues in battery charging mode. In addition, if the ntc_on<1:0>=01b (NTC temperature supervision is active) the

NoBat bit is cleared and charging is restarted, if a NTC resistor with normal or high temperature is detected.

Overvoltage protection for external linear charger:

During charging with the external linear charger the battery charge controller constantly monitors the voltage of the

charge adapter at pin VCHARGER. In case the charge adapter voltage exceeds VVCHIN,MAX rise for longer than

3mesec and bit ChOVDetEn in the Charger Control register is set to 1, charging is disabled immediately. If the voltage

on the pin VCHARGER drops below VVCHIN,MAX fall, the charger is re-enabled.

Figure 19. Typical charging cycle (step down charger)

VBAT = 2V

VSUPPLY = 4.4V

VCHARGER = 6V

VBAT = Vres_rise (e.g: 3.4V)

VSUPPLY = 4.4V (isolate_bat=1)

VSUPPLY = 4.2V (isolate_bat=0)

VBAT = 4.2V

IBAT = 0mA

IBAT = TrickleCurrent (e.g 200mA)

IBAT = ConstantCurrent (e.g 700mA)

Constantvoltage

EOC

CH_DET = 0

CH_DET = 1

NO_CHARGING = 1

NO_CHARGING = 0

I2C Write

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