ADP5065ACBZ-1-R7 datasheet(19/40 Pages) AD

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Data Sheet

ADP5065

Rev. D | Page 19 of 40

Safety Timer

If the watchdog timer (see the Watchdog Timer section for

more information) expires while in charger mode, the ADP5065

charger initiates the safety timer, tSAFE. If the processor has

programmed charging parameters by this time, the ILIM is set to

the default value. Charging continues for a period of tSAFE, then

the charger switches off and sets the CHARGER_STATUS register.

Charge Complete

The ADP5065 charger monitors the charging current while

in constant voltage fast charge mode. If the current falls

below IEND and remains below IEND for tEND, charging stops

and the CHDONE flag is set. If the charging current falls below

IEND for less than tEND and then rises above IEND again, the tEND

timer resets.

Recharge

After the detection of charge complete, and the cessation of

charging, the ADP5065 charger monitors the BAT_SNS pin as

the battery discharges through normal use. If the BAT_SNS pin

voltage falls to VRCH, the charger reactivates charging. Under

most circumstances, triggering the recharge threshold results in

the charger starting directly into fast charge constant voltage

mode.

Battery Charging Enable/Disable

The ADP5065 charging function can be disabled by setting the

I2C EN_CHG bit to low.

THERMAL MANAGEMENT

Isothermal Charging

To assist with the thermal management of the ADP5065

charger, the battery charger provides an isothermal charging

function. As the on-chip power dissipation and die temperature

increase, the ADP5065 charger monitors die temperature and

limits output current when the temperature reaches TLIM

(typically at 115°C). The die temperature is maintained at TLIM

through the control of the charging current into the battery. A

reduction in power dissipation or ambient temperature may

allow the charging current to return to its original value, and

the die temperature subsequently drops below TLIM. During

isothermal charging, the THERM_LIM flag is set to high.

Thermal Shutdown and Thermal Early Warning

The ADP5065 switching charger features a thermal shutdown

threshold detector. If the die temperature exceeds TSD, the

ADP5065 charger is disabled, and the TSD 140°C bit is set. The

ADP5065 charger can be reenabled when the die temperature

drops below the TSD falling limit and the TSD 140°C bit is reset.

To reset the TSD 140°C bit, write to the I2C Fault Register 0x0D

or cycle the power.

Before die temperature reaches TSD, the early warning bit is set if

TSDL is exceeded. This allows the system to accommodate power

consumption before thermal shutdown occurs.

Fault Recovery

Before performing the following operation, it is important to

ensure that the cause of the fault has been rectified.

To recover from a charger fault (when the CHARGER_STATUS

equals 110), cycle power on VINx or write high to reset the I2C

fault bits in the fault register.

BATTERY ISOLATION FET

The ADP5065 charger features an integrated battery isolation

FET for power path control. The battery isolation FET isolates a

deeply discharged Li-Ion cell from the system power supply in

both trickle and fast charge modes, thereby allowing the system

to be powered at all times.

When VINx is below VVIN_OK, the battery isolation FET is in full

conducting mode.

The battery isolation FET is off during trickle charge mode.

When the battery voltage exceeds VTRK, the battery isolation

FET switches to the system voltage regulation mode. During

system voltage regulation mode, the battery isolation FET

maintains the VISO_SFC voltage on the ISO_Sx pins. When the

battery voltage exceeds VISO_SFC, the battery isolation FET is in

full conducting mode.

The battery isolation FET supplements the battery to support

high current functions on the system power supply.

When voltage on ISO_Sx drops below ISO_Bx, the battery

isolation FET enters into full conducting mode.

When voltage on ISO_Sx rises above ISO_Bx, the isolation FET

enters regulating mode or full conduction mode, depending on the

Li-Ion cell voltage and the dc-to-dc charger mode.

ADP5065ACBZ-1-R7 数据表(PDF) 19 Page - Analog Devices

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