ACT8945A datasheet(41/46 Pages) QORVO

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Data Sheet Rev. G, January 2020 | Subject to change without notice

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ACT8945A

Advanced PMU for Atmel SAMA5Dx Series & SAM9 Series Processors

Charge-Control State Machine

PRECONDITION State

new

charging

cycle

begins

with

the

PRECONDITION state, and operation continues in this

state until VBAT exceeds the Precondition Threshold

Voltage. When operating in PRECONDITION state,

the cell is charged at 10% of the programmed

maximum fast-charge constant current, ICHG.

Once VBAT reaches the Precondition Threshold Voltage,

the state machine jumps to the FAST- CHARGE state.

If VBAT does not reach the Precondition Threshold

Voltage

before

the Precondition Time-out period

expires, then the state machine jumps to the TIME-

OUT-FAULT state in order to prevent charging a

damaged cell. See the Charge Safety Timers section

for more information.

FAST-CHARGE State

In the FAST-CHARGE state, the charger operates in

constant-current (CC) mode and regulates the charge

current to the current set by RISET . Charging continues

in CC mode until VBAT reaches the charge termination

voltage (VTERM), at which point the state- machine jumps

to the TOP-OFF state. If VBAT does not reach VTERM

before the total time out period expires then the state-

machine will jump to the “EOC” state and will re-initiate

a new charge cycle after 32ms “relax”. See the Current

Limits

and Charge Current Programming sections for

more information about setting the maximum charge

current.

TOP-OFF State

In the TOP-OFF state, the cell charges in constant-

voltage (CV) mode. In CV mode operation, the charger

regulates its output voltage to the 4.20V charge

termination voltage, and the charge current is naturally

reduced as the cell approaches full charge. Charging

continues until the charge current drops to END-OF-

CHARGE current threshold, at which point the state

machine jumps to the END- OF-CHARGE (EOC) state.

If the state-machine does not jump out of the TOP-

OFF state before the Total-Charge Time-out period

expires, then the state machine jumps to the EOC

state and will re-initiate a new charge cycle if VBAT falls

below termination voltage 205mV (typ). For more

information about the charge safety timers, see the

Charging Safety Times

section.

END-OF-CHARGE (EOC) State

In the END-OF-CHARGE (EOC) state, the charger

presents a high-impedance to the battery, minimizing

battery current drain and allowing the cell to “relax”.

The charger continues to monitor the cell voltage, and

re-initiates a charging sequence if the cell voltage

drops to 205mV (typ) below the charge termination

voltage.

SUSPEND State

The state-machine jumps to the SUSPEND state any

time the battery is removed, and any time the input

voltage either falls below the CHGIN UVLO threshold

or exceeds the OVP threshold. Once none of these

conditions are present, a new charge cycle initiates.

A charging cycle may also be suspended manually by

setting the SUSPEND[ ] bit. In this case, initiate a new

charging sequence by clearing SUSPEND[ ] to 0.

State Machine Interrupts

The charger features the ability to generate interrupts

when the charger state machine transitions, based

upon the status of the CHG_ bits. Set CHGEOCIN[ ] bit

to 1 and CHGSTAT[ ] bit to 1 to generate an interrupt

when the charger state machine goes into the END-OF-

CHARGE (EOC) state. Set CHGEOCOUT[ ] bit to 1 and

CHGSTAT[ ] bit to 1 to generate an interrupt when the

charger state machine exits the EOC state.

CHGDAT[ ] indicates the status of the charger state

machine. A value of 1 indicates that the charger

state machine is in END-OF-CHARGE state, a value of

0 indicates the charger state machine is in other states.

When an interrupt is generated by the charger state

machine, reading the CHGSTAT[ ] returns a value of

1. CHGSTAT[ ] is automatically cleared to 0 upon

reading. When no interrupt is generated by the charger

state machine, reading the CHGSTAT[ ] returns a value

of 0.

For additional information about the charge cycle,

CSTATE[1:0] may be read at any time via I2C to

determine the current charging state.

Table 9:

Charging Status Indication

CSTATE[1] CSTATE[0] STATE MACHINE STATUS

PRECONDITION State

FAST-CHARGE/TOP-OFF State

END-OF-CHARGE State

SUSPEND/DISABLED/

FAULT State

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