Diodes ZXSC300 - Manual

1
ZXSC300
ISSUE 4 - SEPTEMBER 2007
SINGLE OR MULTI CELL LED DRIVER SOLUTION
Q1
FMMT617
R1
0.33R
L1
100µH
V
BATT
LED1
WHITE LED
V
cc
Gnd
I
sense
V drive
U1
ZXSC300
TYPICAL APPLICATION CIRCUIT ORDERING INFORMATION
DEVICE Reel Tapewidth Quantity
per reel
ZXSC300E5TA 7” 8mm 3,000
DEVICE MARKING C300
Package SOT23-5
DESCRIPTION
The ZXSC300 is a single or multi cell LED driver
designed for applications where step-up voltage
conversion from very low input voltages is required.
These applications mainly operate from single 1.5V or
1.2V battery cells. The circuit generates constant
current pulses that are ideal for driving single or
multiple LED’s over a wide range of operating voltages.
The ZXSC300 is a PFM controller IC that drives an
external Zetex switching transistor with a very low
saturation resistance. These transistors are the best
switching devices available for this type of switching
conversion enabling high efficiency conversion with
input voltages below 1 volt. The drive output of the
ZXSC controller generates a dynamic drive signal for
the switching transistor.
FEATURES
•
94% efficiency
•
Minimum operating input voltage 0.8V
•
Fixed output current
•
Low saturation voltage switching transistor
•
SOT23-5 package
The circuit can start up under full load and operates
down to an input voltage of 0.8 volts. The solution
configuration ensures optimum efficiency over a wide
range of load currents, several circuit configurations
are possible depending on battery life versus
brightness considerations.
The ZXSC300 is offered in the SOT23-5 package which,
when combined with a SOT23 switching transistor,
generates a high efficiency small size circuit solution.
The IC and discrete combination offers the ultimate
cost vs performance solution for single cell LED driving
applications.
APPLICATIONS
•
LED flashlights and torches
•
LED backlights
•
White LED driving
•
Multiple LED driving
•
Solar Equipment