YB1518
Step-up DC-DC Converter White LED Driver
Description
The YB1518 is a step-up DC-DC converter;
operates as current source to drive up to 6
white LEDs(VIN at 3.0V) or 8 LEDs(VIN at
3.4V) or 9 LEDs(VIN at 3.4V) in series.
Series connecting of the LEDs provides
identical LED currents resulting in uniform
brightness and eliminating the need for
ballast resistors. The light intensity of these
LEDs is proportional to the current passing
through them. The YB1518 switches at a
fixed frequency of ~1MHz, allowing the use
of tiny, low profile inductors and capacitors
to minimize footprint and cost in space
consideration applications for cellular
phone backlighting or other hand held
equipment.
The YB1518 can drive up to 9 white LEDs
from a single Li-Ion battery. The wide input
voltage range from 2.7V to 16V is ideal for
portable
and
automotive
(5V/12V)
applications
with
higher
conversion
efficiency. To control LED brightness, the
LED current can be pulsed by applying a
PWM (pulse width modulated) signal with a
frequency range of 100Hz to 1KHz to the
CTRL pin.
YB1518 has integrated Latched Over
Voltage Protection that prevents damage to
the device in case of a high impedance
output due to faulty LED or open circuit
caused by abnormal conditions.
Features
Built-in internal switch
2.7V to 16V input range
<1uA shutdown current
High efficiency
Internal Soft Start
Drives up to 9 white LEDs(VIN at 3.4V)
Over voltage protection 36V
Small 5-Lead SOT-23 package
100mV Low Reference Voltage
Applications
LCD Display Module
White LED Backlighting
PDAs, GPS terminals
Digital Cameras
Cellular Phone
Electronic Books
Portable Applications
Typical Application Circuit
Figure 1: Typical Application Circuit
YB1518 MRev.1.2
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YOBON [ YOBON TECHNOLOGIES,INC. ]
