ACT2861 datasheet(40/97 Pages) QORVO

40 / 97 page

Data Sheet Rev. F, April 2022 | Subject to change without notice

40 of 97

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ACT2861

30V Buck-Boost Charger with Integrated MOSFETs and OTG

Battery Full / Charging Termination

The ACT286x terminates a charge cycle when the bat-

tery reaches the termination voltage and the charge cur-

rent drops below the termination current. If the Input cur-

rent limit, Input Voltage limit, or Thermal Regulation loop

is active, the charger will not enter the Charge Full or

Charge Termination states.

Once the termination current and other requirements

are met, the charger transitions from the fast charge

state (FASTCHG) into either the charge full state

(CHGFULL) or charge termination state (CHGTERM).

When EN_TERM=0, the charger enters the CHGFULL

state. The Charge Full state functionality is the same as

the FASTCHG state. The charger can stay in the

CHGFULL state indefinitely. It keeps a fully charged

battery regulated to the VBAT_REG voltage. If some-

thing pulls current from the battery, the charger supplies

current to maintain the battery voltage at VBAT_REG.

The maximum charge current is still limited by the ex-

ternal OLIM resistor and the IFCHG[6:0] register.

When EN_TERM=1, the charger enters the CHGTERM

state. In this state, the charger is disabled and does not

supply any current to the battery. It monitors the battery

voltage to check for the condition when the battery volt-

age

drops

below

VTERM-VRECHARGE.

The

VRECHARGE voltage is typically 100mV or 150mV per

cell. Once the battery voltage drops below the threshold,

the IC enters the Fast Charge state and recharges the

battery.

See the state machine for more details charging and

charge termination.

Charging Safety Timers

The ACT2861 provides two internal charging safety tim-

ers: Low Battery Safety Timer and Fast Charge Safety

Timer

When the Battery Voltage is below VBAT_LOW and in the

charger is in the SCOND or PCOND states, a fixed 120

minute Low Battery Safety Timer is implemented. Dur-

ing this time, the Fast Charge Safety Timer is held in

reset and not active. If the Low Battery Safety timer

times out, the IC goes to the Charging Fault state until

it is reset – See below on how to clear the Low Battery

Safety Timer.

The Low Battery Safety Timer stops if the battery tem-

perature causes the converter to stop switching and en-

ter the SCSUSPEND or PCSUSPEND states. The Low

Battery Safety Timer runs at ½ speed if the Input Volt-

age, Input Current, or Die Temperature regulations

loops become active. This increases the overall time of

120 minute timer.

When the Battery Voltage is above VBAT_LOW the Fast

Charge Safety Timer is enabled and the Low Battery

Safety timer is held in reset. The Fast Charge Safety

Timer

controlled

with

the

I2C

bits

FC_SAFETY_TIMER[4:0] in register 0x1Bh. It is config-

urable between 30 minutes and 16 hours. If the Fast

Charge safety timer expires, the IC goes into the Charg-

ing Fault state and charging is disabled until the Fast

Charge Safety Timer is reset.

Both the Low Battery Safety and Fast Charge Safety

Timers can be fully disabled and reset via the I2C bit

DIS_SAFETY_TIMER in register 0x1Bh or manually

suspended

using

the

I2C

bit

SUS-

PEND_SAFETY_TIMER in register 0x1Bh.

Both safety timers are automatically stopped any time

the charging is enabled but charging has suspended.

This occurs when the battery temperature exceeds the

allowable temperature limits.

Both safety timers also run at ½ speed when VIN Input

Regulation, IIN Current Regulation, or Die Thermal

Regulation are active to increase the overall safety timer

windows.

Additionally, the Fast Charge Safety Timer runs at ½

speed in some JEITA charging modes. See the JEITA

Battery Temperature Control paragraph for more details.

Both safety timers are reset when any of the following

occur:

Charging State Machine enters RESET state

DIS_SAFETY_TIMER register is set High

Charging has completed. This includes enter-

ing either the CHGFULL or CHG TERM states.

IC exits the Charge Mode via the EN_CHG pin,

OVERRIDE_EN_CHG, HIZ Registers, etc.

ACT2861 Datasheet(PDF) 40 Page - Qorvo, Inc

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