X RP 6 8 4 0
4.3A Supercapacitor Flash LED Driver with I
2
C
December 2009
Rev. 1.0.0
GENERAL DESCRIPTION
The XRP6840 is a controlled-current dual-cell
supercapacitor charger and high power LED
driver. Operating from a standard lithium-ion
battery, the XRP6840 provides up to 4.3A of
programmable Flash LED current and up to
600mA
and
5.6V
of
programmable
supercapacitor charging current and voltage.
Architectured around a 2.4MHz tri-mode 1x,
1.5x and 2x charge pump, the XRP6840
charges the stacked supercapacitor to the
programmed output voltage with no more
than 600mA drawn from the battery. While
charging, an internal active balance circuitry
insures matching of the stacked capacitors’
voltages.
A standard 2-line I C serial interface allows
the dynamic programming of LED currents in
torch and flash modes, flash timeout, channel
enable, gain control, capacitor charge voltage,
and enable. The XRP6840 comes in a 2 and 3
channel
version
supporting
respectively
440mA/2.15A per channel and 300mA/1.45A
in torch/flash modes.
The flexibility designed into the XRP6840 can
also allow it to reverse the power flow back to
the input to prevent unintended system resets
as the battery voltage drops.
The XRP6840 is available in a lead-free,
“green”/halogen free 20-pin TQFN package.
2
APPLICATIONS
•
High Power Torch/Strobe/Flash LED
•
High Resolution Cameras
•
Generic High Power Lighting
•
High Power White LED Backlighting
FEATURES
•
Programmable 4.3A Flash LED Driver
−
Torch and Flash Modes
−
2 and 3 Channels Versions
•
Programmable Supercapacitor Charger
−
600mA Adjustable Charging Current
−
Programmable Supercapacitor Voltage
−
In-rush Current Control
−
Active Voltage Balance Control
•
Tri-mode Charge Pump Architecture
−
1x, 1.5x, 2x Operation Modes
−
2.4MHz Switching Frequency
•
I
2
C Serial Interface
•
Thermal, Over Current and Output
Short Protection
•
LED Short Detection
•
RoHS Compliant “Green”/Halogen Free
20-pin 4mmx4mm TQFN package
TYPICAL APPLICATION DIAGRAM
Fig. 1: XRP6840 – 3 Channels Application Diagram
Exar Corporation
48720 Kato Road, Fremont CA 94538, USA
www.exar.com
Tel. +1 510 668-7000 – Fax. +1 510 668-7001
EXAR [ EXAR CORPORATION ]
