WLED Driver. YB1521 Datasheet

YB1521 Datasheet PDF, Equivalent


Part Number

YB1521

Description

High Power Step-Up DC-DC Converter & WLED Driver

Manufacture

YOBON TECHNOLOGIES

Total Page 9 Pages
PDF Download
Download YB1521 Datasheet PDF


YB1521 Datasheet
www.DataSheet4U.com
YB1521
High Power Step-Up DC-DC Converter & WLED Driver
Description
The YB1521 is a step-up DC-DC converter
which operating as current source to drive
up 45 white LEDs (3S15P) in parallel /
series configuration from a 5V system rail.
Series connecting of 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 YB1521 is a fixed
frequency of 1.3MHz, 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 wide input voltage range from 2.5V to
5.5V is idea for portable applications with
higher conversion efficiency. To control
LED brightness, the LED current can be
pulsed by applying a PWM signal with a
frequency which is typically 50 KHz to the
EN pin.
Features
2.5V to 5.5V Input Voltage Range
Built In Power MOSFET
Drive Up to 15V @400mA at 5V Vin
Less than 1µA Shutdown Current
Up to 94% efficiency
Over Voltage Protection@18V
UVLO, Thermal Shutdown
Internal 1.6A Current Limit
200mv Low Reference Voltage
Built In Soft Start
PWM Dimming
SOT23-5 Package
Green Package (RoHS) Available
Applications
Cellular and Smart Phones
Handheld Computers and PDAs
Small LCD Displays
GPS Terminals
MP3 Players
Digital Still and Video Cameras
Electronic Books
Typical Application Circuit
VI = 4.5~5.5V
4.7u/1 V
O
I
E
GN
L1
6 .8u
D1
Schottk
4.7u/2 V
S
YB1521
F
15 strings
R1
Figure 1: Typical Application Circuit
100
90
80
70
60
50
4
Efficiency vs. Input Voltage
IOUT =100mA
L=10μH
IOUT =180mA
4.5 5
INPUT VOLTAGE (V)
5.5
Figure 2: Efficiency
6
YB1521 MRev.1.1
www.yobon.com.tw
1

YB1521 Datasheet
www.DataSheet4U.com
YB1521
High Power Step-Up DC-DC Converter & WLED Driver
Pin Configuration
Figure 3: Pin Configuration
Pin Assignment & Description
Table1
Pin
1
2
3
4
5
NAME
SW
GND
FB
EN
IN
Description
Switching Pin. This is the drain of internal power MOSFET
switch. Connect the power inductor and output rectifier to SW.
Ground pin. Connect directly to local ground plane.
Feedback Pin. Reference voltage is 200mV. Connect LEDs and
a resistor at this pin. LED current is determined by the
resistance and FB voltage.
Shutdown Pin and Dimming Control Pin. PWM duty cycle
controls the LED current.
Input Supply Pin. Bypass this pin with a capacitor as close to
the device as possible.
Ordering Information
Table2
Order Number Package Type
Supplied As
YB1521ST25
SOT23-5 3000 Units Tape & Reel
Package Marking
Y521
YB1521 MRev.1.1
www.yobon.com.tw
2


Features Datasheet pdf www.DataSheet4U.com YB1521 High Power S tep-Up DC-DC Converter & WLED Driver Fe atures 2.5V to 5.5V Input Voltage Range Built In Power MOSFET Drive Up to 15V @400mA at 5V Vin Less than 1µA Shutdow n Current Up to 94% efficiency Over Vol tage Protection@18V UVLO, Thermal Shutd own Internal 1.6A Current Limit 200mv L ow Reference Voltage Built In Soft Star t PWM Dimming SOT23-5 Package Green Pac kage (RoHS) Available Description The YB1521 is a step-up DC-DC converter whi ch operating as current source to drive up 45 white LEDs (3S15P) in parallel / series configuration from a 5V system rail. Series connecting of LEDs provide s identical LED currents resulting in u niform brightness and eliminating the n eed for ballast resistors. The light in tensity of these LEDs is proportional t o the current passing through them. The YB1521 is a fixed frequency of 1.3MHz, allowing the use of tiny low profile i nductors and capacitors to minimize foo tprint and cost in space consideration applications for cellular.
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