L6924U STMicroelectronics, L6924U Datasheet - Page 19

• Manufacturer Part Number: L6924U
• Description: Battery Management USB Battery Charger System w/integra
• Manufacturer: STMicroelectronics

Specifications of L6924U

• Product: Charge Management
• Battery Type: Li-Ion
• Output Voltage: 4.2 V
• Output Current: 30 mA
• Maximum Operating Temperature: + 125 C
• Minimum Operating Temperature: - 40 C
• Package / Case: VFQFPN
• Mounting Style: SMD/SMT
• Lead Free Status / Rohs Status: Lead free / RoHS Compliant

L6924U
Equation 6
Where V
9500.
Figure 11. I
In USB mode (MODE pin high), the R
Equation 7
Where V
The charge current in USB mode depends on R
When this pin is high, the “high-power” USB mode is selected and the charge current is
determined by the equation 7.
The charge current in USB mode should be set in accordance with the typical USB current
capability (up to 500 mA). If ISEL is low, the “low-power” USB mode is selected and the
charge current is a fifth of the high-power USB mode charge current (up to 100 mA)
During low power USB mode operation, since the charge current is reduced by one fifth, the
maximum charging time is proportionally increased (
Figure 12. I
Regardless of the operation mode (AC adapter or USB), during the fast-charge phase the
battery voltage increases until it reaches the programmed output voltage (4.2 V). A safety
timer is also present. If the Fast-charge phase does not finish within the programmed time
(see
Chapter 7.7: Maximum charging time on page 21
BG
BG
is the internal reference equal to 1.23 V, whereas K
and K
AC
USB
pin connection
PRG
pin connection
have the same meaning and value above mentioned.
Doc ID 14716 Rev 2
R
R
USB
USB
AC
=
=
resistor can be selected as:
⎛
⎜
⎜
⎝
⎛
⎜
⎜
⎝
V
I
I
Applications information: charging process
V
USB
AC
BG
BG
USB
⎞
⋅ ⎟ ⎟
⎠
⎞
⋅ ⎟ ⎟
⎠
K
K
PRG
PRG
as well as the state of the ISEL pin.
Section 7.7: Maximum charging time
), a fault is given.
PRG
is a constant equal to
19/37
).