L6924U

Operation description

Doc ID 14716 Rev 2

15/37

Where

ΔV

Equation 3

Where,

The difference between the programmed charge current and the adapter limit should be

control loop completely unbalanced and the power element is fully turned on.

Figure 8

adapter current limit of 500 mA.

Figure 8.

Neglecting the voltage drop across the charger (

ΔV

condition, its input voltage is equal to the battery one, and so a very low operating input

voltage (down to 2.5 V) is required. The power dissipated by the device during this phase is:

Equation 4

When the battery voltage approaches the final value, the charger gets back the control of

the current, reducing it. Due to this, the upstream adapter exits the current limit condition

dissipation:

I

R

V

LIM

)

ON

(

DS

MOS

×

=

Δ

2

LIM

)

on

(

DS

CH

I

R

P

×

=