DocID024974 Rev 3

19/30

PM6613N

Operating description

Equation 1

the charge current limit.

4.7

Adapter constant power function

The adapter constant power function manages the amount of input current flowing to the

system and to the battery during a charging process. If the input current exceeds the chosen

input current limit, the PM6613N keeps the input current at the limit decreasing the charging

current. In this manner the system load has the priority. As the system load current

increases, the charging current linearly decreases down to 0 A. The input current is sensed

measuring the differential voltage between ACP and ACN pins where a small resistor is

connected. A suggested value is 10 m

Ω, and eventually not more than 20 mΩ. Greater

values increase the sensitivity and a finer current limit management, but cause a higher

power loss and could lead to an overcurrent protection due to a higher voltage ripple. The

INPUT_AMP register sets the input current limit through SMBus. Valid ranges are between

128 mA and 16256 mA. Any attempt to write a value outside this range causes the register

to be cleared and any charging process to be stopped.

Table 11. Valid battery charge voltage ranges for Li-Ion battery cells

Cells

CHRG_VOLT

Charge voltage [mV]

Min.

Max.

Min.

Max.

2

0x1F40

0x2338

8000

9016

3

0x2EE0

0x34D4

12000

13524

4

0x3E80

0x4670

16000

18032

Cells

CHRG_VOLT

Charge voltage [mV]

Min.

Max.

Min.

Max.

2

0x1A90

0x1E88

6800

7816

3

0x27D8

0x2DCC

10200

11724

4

0x3520

0x3D10

13600

15632

V

ILIM

R

SB

I

CHG

10

0.03125

+

⋅⋅

=