ETA3001

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8

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ETA3001 Rev 1.2

The ETA3001 timing diagram for state machine is shown in following figure.

Figure 4: Timing Profile

UNBALANCE DETECTION

When state is in CHECK State, ETA3001 detects VKICK difference between 2 cells to enter BALANCE State.

If the top cell voltage is higher, balancing will be “DOWN”, meaning discharge the top cell to charge to

bottom cell. And if the bottom cell voltage is higher, balancing will be “UP”, meaning discharge the bottom

cell to charge to top cell.

BALANCING PROFILE

ETA3001 balancing always starts with “Constant Current

Regulation” phase since it is always with high voltage

difference. Constant current is set by RISET.

When the detected difference at IC pin is almost zero, but due

to battery equivalent series resistance, real difference is not

zero, then current is not immediately zero but reduced slowly

depend on battery capacitance. This condition is called

“Current Dimming” phase.

When two cell voltages are equal, balancing current becomes

almost zero, when this persist for a time period of TDONE, the

balancing finishes one cycle, and ETA3001 goes back to

SLEEP State.

Figure 5:

Balancing Profile

PROTECTION

ETA3001 provides full protection to batteries that extend the life time of the batteries:

➢

Short and Low Voltage Protection: When either of the cell voltage below VPRECOND, maximum

balancing current will be re-defined to 10% of the level set by ISET pin resistor.

➢

Open and Over Voltage Protection: When either of the cell voltage is greater than VOVP, ETA3001

will stop balancing, and go back to SLEEPING. Part will wake up after TSLEEP.

➢

Thermal Shutdown: When part gets hotter than 160oC, ETA3001 will stop balancing, and go back

to SLEEPING. Part will wake up after TSLEEP.

➢

Current Limit Protection: Maximum of the peak of inductor current is allowed to 5.5A.

nUVLO and

EN

2s TIMER

TCHECK

BALANCING

DONE

TSLEEP

TSLEEP

Constant

Current

Current

Dimming

Skip

TDONE

Delta Voltage

(At IC pin Measurement)

TDONE

Constant Current

Current Dimming

Inductor Current