L6924UTR datasheet(21/37 Pages) STMICROELECTRONICS

Part #	L6924UTR

Description	USB compatible battery charger system with integrated power switch for Li-Ion/Li-Polymer

PDF	37 Pages

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Manufacturer	STMICROELECTRONICS [STMicroelectronics]

Direct Link	http://www.st.com

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21 / 37 page

L6924U

Applications information: charging process

Doc ID 14716 Rev 2

21/37

7.5

Recharge flow chart

Figure 14.

Recharge flow chart

7.6

Recharge threshold

When, from an end-of-charge condition, the battery voltage goes below the recharging

threshold (VRCH), the device goes back in charging state. The value of the recharge

threshold is 4.05 V.

7.7

Maximum charging time

To avoid the charging of a dead battery for a long time, the L6924U has the possibility to set

a maximum charging time starting from the beginning of the fast-charge phase. This timer

can be set through a capacitor, connected between the TPRG pin and GND. CTPRG is the

external capacitor (in nF) and is given by the following equation:

Equation 10

Note:

The maximum recommended CTPRG value must be less than 50 nF.

⎟

⎠

⎞

⎜

⎝

⎛

REF

PRG

MAXCH

TPRG

L6924UTR Datasheet(PDF) 21 Page - STMicroelectronics