YB1517 Datasheet, PDF (1/10 Pages) YOBON TECHNOLOGIES,INC. – Step-up DC-DC Converter & White LED Driver

YB1517
Step-up DC-DC Converter & White LED Driver
Description
The YB1517 is a Current-mode PWM
step-up DC-DC converter. It can drive up to
18V in 20mA output current conditions
while Vin at 3.0V and 20V at 3.5Vin. The
900 KHz switching frequency allows it to
work with tiny external components,
therefore minimize the footprint and cost in
space consideration products.
One of the major applications for YB1517
is in the dc to dc converter and OLED
power supply and TFT panel power supply.
When using YB1517 for white LED driving,
it is not recommended to control LED
brightness by applying a PWM signal to the
CTRL pin, because the built-in soft-start
circuit might interfere the start-up operation
of YB1517 and cause lower brightness. It
operates as current source to drive up to 6
white LEDs in series at 3.3V input. 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.
YB1517 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
„ 900KHz Current-mode PWM Converter
„ Built-in Internal Switch
„ Adjustable Output Voltage up to 20V
„ 2.7V to 16V Input Range
„ <1uA Shutdown Current
„ Internal Soft Start
„ Drives up to 6 White LEDs
„ Tiny Inductor and Capacitors Allowed
„ Over Voltage Protection 30V
„ Small 5-Lead SOT-23 Package
„ 220mV Low Reference Voltage
„ Green package (RoHS) available
Applications
„ LCD Display Module
„ White LED Backlighting
„ PDAs, GPS Terminals
„ Digital Cameras
„ Cellular Phone
„ Electronic Books
„ Portable Applications
Typical Application Circuit
YB1517 Rev.1.4
www.yobon.com.tw
1