ZXSC300 Datasheet, PDF (1/12 Pages) Zetex Semiconductors – SINGLE OR MULTI CELL LED DRIVER SOLUTION

SINGLE OR MULTI CELL LED DRIVER SOLUTION
ZXSC300
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.
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.
FEATURES
• 94% efficiency
• Minimum operating input voltage 0.8V
• Fixed output current
• Low saturation voltage switching transistor
• SOT23-5 package
TYPICAL APPLICATION CIRCUIT
ORDERING INFORMATION
V_BATT
L1
100µH
U1
V_cc
V_drive
I_sense
Gnd
ZXSC300
Q1
FMMT617
LED1
WHITE LED
DEVICE
ZXSC300E5
R1
0.33R
Package
SOT23-5
Partmarking
C300
ISSUE 1 - JUNE 2001
1