DATA BRIEF
For further information contact your local STMicroelectronics sales office.
Rev 1
July 2005
CD00061067
1/5
5
L6924D
Li-Ion/Li-Polymer Battery Charger System with
Integrated Power Switch
Features
Fully integrated solution with Power pass
MOSFET, reverse blocking diode, sense
resistor and thermal protection
Ideal for Coke and Graphite anode Single cell
Li-Ion packs
Both Linear and Quasi Pulse operation
Programmable charge current
Programmable Pre-Charge voltage threshold
1% output voltage accuracy
Status outputs to drive LEDs or Host Processor
interface
Programmable charge timer and charge end
current
Small VFQFPN package (3mm x 3mm)
Low thermal resistance: 80C/W
Charge current thermal loop
Applications
PDA's
Handheld Devices
Cellular Phones
Digital Cameras
Stand-alone Chargers
Usb Powered Chargers
Mp3 Players
Description
The L6924D is a fully monolithic linear battery
charger, ideal for coke and graphite anode single
cell Li-Ion packs that allows a charge
management system in a very compact
application.
It is the ideal way for space limited applications,
like PDA's, hand held, cellular phones and digital
cameras. It is realized in BCD6 technology and, in
a small VFQFPN 3x3 16 pins package, that
integrates all the power elements (the Power pass
MOSFET, the reverse blocking diode and the
sense resistor).
The maximum application flexibility of the L6924D,
is given by the possibility of programming all the
features (like pre-charging current, charging
current, the pre-charging voltage threshold, the
end of charge current threshold and the charging
time). When a real basic external wall adapter is
used, the L6924D works in Linear Mode and
charges the battery in a CC/CV (Constant current/
Constant voltage) profile.
Order codes
VFQFPN 16
Part number
Package
Packing
L6924D
VFQFPN 16
Tube
www.st.com
L6924D
2/5
CD00061067
However, when a current-limited adapter is used, the device works in Quasi Pulse Mode thanks to its low
input voltage. The device has an operating input voltage ranging from 2.5V to 14V. On the L6924D is
possible to select the output voltage (4.1V-4.2V) with 1% voltage accuracy.
This allows to use both coke and graphite anode cells. The L6924D offers two open collector outputs, for
diagnostic purpose, which can be used to drive two external LEDs, or to communicate with a host
microcontroller.
Moreover, the voltage across the resistor connected between IEND and GND gives the status about the
charging current (working as a gas gauge) and some eventual faults, like battery over temperature, the
battery absence and the over time charge.
Figure 1.
Basic Application Diagram
Figure 2.
Demo Board Layout
SHDN
ON
OFF
GND
V
OPRG
I
PRE
T
PRG
V
PRE
I
PRG
I
END
V
OSNS
V
OUT
TH
V
REF
V
INSNS
V
IN
ST1
ST2
L6924D
CHARGER
BATTERY
Li-Ion cell
R3
C2
NTC
C1
C3
SHDN
ON
OFF
GND
V
OPRG
I
PRE
T
PRG
V
PRE
I
PRG
I
END
V
OSNS
V
OUT
TH
V
REF
V
INSNS
V
IN
ST1
ST2
L6924D
CHARGER
BATTERY
Li-Ion cell
R3
C2
NTC
C1
C3
L6924D
CD00061067
5/5
Information furnished is believed to be accurate and reliable. However, STMicroelectronics assumes no responsibility for the consequences
of use of such information nor for any infringement of patents or other rights of third parties which may result from its use. No license is granted
by implication or otherwise under any patent or patent rights of STMicroelectronics. Specifications mentioned in this publication are subject
to change without notice. This publication supersedes and replaces all information previously supplied. STMicroelectronics products are not
authorized for use as critical components in life support devices or systems without express written approval of STMicroelectronics.
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All other names are the property of their respective owners
2005 STMicroelectronics - All rights reserved
STMicroelectronics group of companies
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