ACT81460 datasheet(49/60 Pages) ACTIVE-SEMI

49 / 60 page

ACT81460

Rev 1.0, 18-Dec-2018

Innovative PowerTM

www.active-semi.com

ActiveSwitcherTM is a trademark of Active-Semi

to a maximum of 5.5V by the Smart Switch. The VSYS

output powers the rest of the system and the other con-

verters. The Smart Switch doubles as a linear regulator

to regulate VSYS to voltages lower than VIN.

Softstart

The Smart Switch provides softstarting to the VSYS out-

put when input power is applied. This provides a 500µs

controlled ramp time to limit inrush currents.

Overvoltage Blocking

The Smart Switch continuously monitors the VIN volt-

age. If VIN goes above the 5.7V overvoltage threshold,

the switch opens to protect the VSYS bus and all down-

stream loads. It has a 20V blocking capability to handle

extreme overvoltage conditions. When an overvoltage

condition occurs, the ACT81460 opens the Smart

Switch to protect VSYS from the overvoltage condition.

VSYS Regulator

The Smart Switch regulates VSYS to 4.8V. This pro-

vides a constant VSYS operating voltage, even when

VIN varies. Contact Active Semi if a different VSYS reg-

ulation voltage is required. If VIN is lower than the pro-

grammed regulation voltage, the Smart Switch fully

turns on with a resulting resistance of 200mΩ.

Linear Charger

The ACT81460 autonomously charges a single cell Li-

Ion battery. The IC automatically detects the battery’s

state of charge and starts charging in the proper charge

state. It completes full or partial charging cycles without

host intervention. The charger includes all Li-Ion charg-

ing modes and protection including trickle charging, pre-

charge, fast charge, over and under voltage protection,

JEITA charging profiles, and thermal regulation. It also

includes Active Semi’s ActivePath Architecture.

Charger Enable

The charger is automatically enabled when the VSYS

voltage is greater than the battery voltage by > 100mV.

The charger can be enabled and disabled by I2C bit

CHG_EN.

Battery Charging Profile

The IC follows the standard Li-Ion battery charge profile

with four charging phases: trickle charge, precondition-

ing, constant current, and constant voltage. The battery

charge current is a function the battery voltage and the

IC’s hardware and register settings. Figure 2 shows the

charge profile and Table 9 shows these available set-

tings.

VBAT

Charging

Current

Current set by

< VTRICKLE

ITRICKLE

I2C Configurable: 10mA,

25mA

VTRICKLE ~ VPRE

IPRE

I2C Configurable: 5%,

10%, 15%, 20% of ICHG

current

VPRE ~ VTERM

ICHG

Hardware Configurable:

10mA to 800mA

> VTERM

None

Table 9: Charging Current Settings

Trickle Charge – When the battery voltage is lower

than the battery short threshold voltage, VBAT_SHORT, the

battery can only accept very low charge currents. The

charger supplies a trickle charge current, ITRICKLE, to

condition the battery and bring a shorted battery pack

“back to life” by allowing the battery protection circuitry

to close its protection FETs. The battery can then be

safely charged to bring the voltage up to a level where

preconditioning can begin.

VTRICKLE is set to 2.0V, 2.2V, 2.4V, or 2.5V via I2C regis-

ter bits V_TRICKLE[1:0].

ITRICKLE is set to 10mA or 25mA via I2C register

I_TRICKLE_SET.

Precondition Charge - When the battery voltage is

higher than the trickle voltage threshold, the precondi-

tion charge phase begins. In this phase, the IC charges

the battery at a reduced charge current. This safely con-

ditions the battery chemistry to prepare the battery to

accept the full charging current.

The precondition voltage threshold, VPRE, is set via I2C

grammable between 2.7V to 3.4V. The following equa-

tion calculates the precharge voltage.

��

2.7��

50�� ∗ �� 3: 0

Where VPRE[3:0] is the decimal equivalent value in this

the precharge voltage = 3.0V.

The precharge current, IPRE, is set by I2C register bits

IPRE[1:0]. The constant current is set to 5%, 10%, 15%

or 20% of the fast charge current setting.

The constant current, precondition phase continues un-

til the battery voltage increases to the precondition volt-

age threshold.

ACT81460 Datasheet(PDF) 49 Page - Active-Semi, Inc

ACT81460 Datasheet(HTML) 49 Page - Active-Semi, Inc

Html Pages

1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60

Datasheet Download

Link URL