L6924D STMicroelectronics, L6924D Datasheet - Page 14

• Manufacturer Part Number: L6924D
• Description: IC BATTERY CHARGER SYS 16-VFQFPN
• Manufacturer: STMicroelectronics

Specifications of L6924D

• Function: Charge Management
• Battery Type: Lithium-Ion (Li-Ion), Lithium-Polymer (Li-Pol)
• Voltage - Supply: 2.5 V ~ 12 V
• Operating Temperature: -40°C ~ 125°C
• Mounting Type: Surface Mount
• Package / Case: 16-VFQFN
• Product: Charge Management
• Output Current: 30 mA
• Operating Supply Voltage: 2.5 V to 12 V
• Maximum Operating Temperature: + 125 C
• Minimum Operating Temperature: - 40 C
• Mounting Style: SMD/SMT
• For Use With: 497-8428 - BOARD EVAL CHARGER ST7260/L6924D497-8247 - BOARD EVAL FOR L6924UTR497-5504 - EVAL BOARD FOR L6924D
• Lead Free Status / RoHS Status: Lead free / RoHS Compliant

Operation description
6.2
14/38
Quasi-pulse mode
The quasi-pulse mode can be used when the system can rely on the current limit of the
upstream adapter to charge the battery. In this case, I
current limit of the adapter. In this mode, the L6924D charges the battery with the same
three phases as in linear mode, but the power dissipation is greatly reduced as shown in
Figure
Figure 7.
The big difference is due to the fact that I
During the fast-charge phase, the output voltage of the adapter drops and goes down to the
battery voltage plus the voltage drop across the power MOSFET of the charger, as shown in
the following equation:
Equation 2
Where ΔV
Equation 3
V
V
O PRGTH
I
PRETH
V
PRETH
I
I
CHG
7.
ADP
LIM
MOS
Pre-Charge
Typical charge curves in quasi pulse mode
Phase
is given by:
Doc ID 11908 Rev 9
Fast-Charge
V
IN
Phase
Δ
=
V
V
ADP
MOS
Ilim x Rdson
CHG
=
=
R
is higher than the current limit of the adapter.
V
DS
BAT
(
ON
)
+
×
I
Δ
CHG
LIM
V
Voltage Regulation
MOS
must be set higher than the
Adapter Voltage
Power dissipation
Charge Current
Phase
Battery Voltage
Charge
End
L6924D