ACT8945A datasheet(38/46 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

LED indicator or provide a logic-level status signal to

the host microprocessor

Dynamic Charge Current Control (DCCC)

The ACT8945A's ActivePath charger features dynamic

charge current control (DCCC) circuitry, which acts to

ensure

that

the

system

remains powered while

operating within the maximum output capability of the

power adapter. The DCCC circuitry continuously

monitors VVSYS, and if the voltage at VSYS drops by

more than 200mV, the DCCC circuitry automatically

reduces charge current in order to prevent VVSYS from

continuing to drop.

Charge Current Programming

The

ACT8945A's

ActivePath

charger

features

flexible charge current-programming scheme that

combines the convenience of internal charge current

programming with the flexibility of resistor based

charge current programming. Current limits and charge

current programming are managed as a function of the

ACIN and CHGLEV pins, in combination with RISET, the

resistance connected to the ISET pin.

ACIN is a logic input that configures the current-limit of

ActivePath

's linear regulator as well as that of the

battery charger. ACIN features a precise 1.2V logic

threshold, so that the input voltage detection threshold

may be adjusted with a simple resistive voltage

divider. This input also allows a simple, low- cost dual-

input charger switch to be implemented with just a

few, low-cost components.

When the voltage at ACIN is above the 1.2V

threshold, the charger operates in “AC-Mode” with a

charge current programmed by RISET, and the RISET is

given by:

RISET (kΩ) = 2336 × (1V/ICHG (mA)) - 0.205

With a given RISET then charge current will reduce 5

times when CHGLEV is driven low.

When ACIN is below the 1.2V threshold, the charger

operates in “USB-Mode”, with a maximum CHGIN

input current and charge current defined by the

CHGLEV input; 450mA, if CHGLEV is driven to a logic-

high, or 100mA, if CHGLEV is driven to a logic-low.

The

ACT8945A's

charge

current

settings

are

summarized in Table 8.

Note that the actual charge current may be limited to

a current lower than the programmed fast charge

current due to the ACT8945A’s internal thermal

regulation loop. See the Thermal Regulation section for

more information.

Charger Input Interrupts

In order to ease input supply detection and eliminate

the size and cost of external detection circuitry, the

charger has the ability to generate interrupts based

upon the status of the input supply. This function is

capable of generating an interrupt when the input is

connected, disconnected, or both. An interrupt is

generated any time the input supply is connected when

INSTAT[ ] bit is set to 1 and the INCON[ ] bit is set to

1, and an interrupt is generated any time the input

supply is disconnected when INSTAT[ ] bit is set to 1

and the INDIS[ ] bit is set to 1.

INDAT[ ] indicates the status of the CHGIN input

supply. A value of 1 indicates that a valid CHGIN

input (CHGIN UVLO Threshold<VCHGIN<CHGIN OVP

Threshold) is present, a value of 0 indicates a valid

input is not present.

When an interrupt is generated by the input supply,

reading the INSTAT[ ] returns a value of 1. INSTAT

[ ] is automatically cleared to 0 upon reading. When

no interrupt is generated by the input supply, reading

the INSTAT[ ] returns a value of 0.

When responding to an Input Status Interrupt, it is

often useful to know the state of the ACIN input. For

example, in a dual-input charger application knowing

the state of the ACIN input can identify which type

of input supply has been connected. The state of the

ACIN input can be read at any time by reading the

ACINSTAT[ ] bit, where a value of 1 indicates that

the voltage at ACIN is above the 1.2V threshold

(indicating that a wall-cube has been attached), and a

value of 0 indicates that the voltage is below this

threshold (indicating that ACIN input is not valid and

USB supply input is selected).

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