ETA9185

www.etasolution.com

6

Empower Thinkers

APPLICATION INFORMATION

ETA9185 is an ultra low power 5V boost converter, 20V linear charger and fuel gauge all-in-one solution for TWS

charge cradle, boost converter with true-shutoff function.

Normal Charge Cycle

The ETA9185 initiates a charge cycle once the voltage at the VIN pin rises above the UVLO threshold level. A 1%

precision resistor needs to be connected from the ISET pin to ground. If the voltage at the BAT pin is less than 3.0V,

the charger enters trickle charge mode. In this mode, the charge current is reduced to nearly 1/10 the programmed

value until the battery voltage is raised to a safe level for full current charging.

The charger switches to constant-current mode as the BAT pin voltage rises above 3.0V, the charge current is thus

resumed to full programmed value. When the final VBAT voltage (4.2V or 4.35V) is reached, the ETA9185 enters

constant-voltage mode and the charge current begins to decrease until it drops to 1/10 of the preset value and ends

the charge cycle.

Programming Charge Current

The charge current is programmable by setting the value of a precision resistor connected from the ISET pin to ground.

The charge current out of the BAT pin can be using the following equation:

IBAT=

1

Rset

×1000

LED Display Mode

The ETA9185 use D1, D2, D3, D4 LEDS to show the battery voltage level.

Table 1

D1, D2, D3, D4 Battery Voltage Level Indicator

State

Battery Voltage Level(C)

D1

D2

D3

D4

Charging

C≤25%

1Hz flash

off

off

off

25%<C≤50%

on

1Hz flash

Off

off

50%<C≤75%

on

on

1Hz flash

off

75%<C

on

on

on

1Hz flash

Charging Done

on

on

on

on

Discharging

75%<C≤100%

on

on

on

on

50%<C≤75%

on

on

on

Off

25%<C≤50%

on

on

off

off

3%<C≤25%

on

off

off

off

C≤3%

1Hz flash

off

off

off