Datasheet

Application ideas L6924D
34/38 Doc ID 11908 Rev 9
10 Application ideas
10.1 USB battery charger
With a voltage range between 4.75 V and 5.25 V, and a maximum current up to 500 mA, the
USB power bus is an ideal source for charging a single-cell Li-Ion battery. Since it is not
possible to rely on the USB current limit to charge the battery, a linear approach must be
adopted. Therefore, it is only necessary to set the I
CHG
with a maximum value lower than
500 mA, and the device will charge the battery in Linear mode.
Figure 29 shows an example of USB charger application schematic.
Figure 29. USB charger application
L6924D
V
IN
V
INSNS
T
PRG
ST1
ST2
SD
GND
TH
V
OPRG
I
PRE
V
PRE
I
PRG
V
OSNS
V
OUT
I
END
V
REF
R1
R2 R3
R4
R5
C1
C2
C3
C4
BATTERY
PACK
V
BUS
GND
D- D+
SYSTEM
AND
USB
CONTROLLER