yb1521 YOBON TECHNOLOGIES,INC., yb1521 Datasheet

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yb1521

Manufacturer Part Number
yb1521
Description
High Power Step-up Dc-dc Converter & Wled Driver
Manufacturer
YOBON TECHNOLOGIES,INC.
Datasheet

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Company
Part Number
Manufacturer
Quantity
Price
Part Number:
yb1521ST25
Manufacturer:
YOBON
Quantity:
20 000
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
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
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.
Typical Application Circuit
YB1521 MRev.1.1
4.7u/ 1 V
VI
O
= 4.5~5.5V
Figure 1: Typical Application Circuit
connecting
E
GN
I
applications
YB1521
L 1
6.8u
of
High Power Step-Up DC-DC Converter & WLED Driver
LEDs
S
F
D1
Schottk
for
4.7u/2 V
provides
www.yobon.com.tw
cellular
15 string
R 1
s
Features
Applications
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
Cellular and Smart Phones
Handheld Computers and PDAs
Small LCD Displays
GPS Terminals
MP3 Players
Digital Still and Video Cameras
Electronic Books
100
90
80
70
60
50
4
Efficiency vs. Input Voltage
Figure 2: Efficiency
4.5
I
I
OUT
OUT
INPUT VOLTAGE (V)
=100mA
=180mA
5
YB1521
5.5
L=10μH
1
6

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yb1521 Summary of contents

Page 1

... 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 identical LED currents resulting in uniform brightness and eliminating the need for ballast resistors ...

Page 2

... LED current. Input Supply Pin. Bypass this pin with a capacitor as close the device as possible. Ordering Information Table2 Order Number Package Type YB1521ST25 SOT23-5 YB1521 MRev.1.1 Figure 3: Pin Configuration Description Supplied As 3000 Units Tape & Reel www.yobon.com.tw YB1521 Package Marking Y521 2 ...

Page 3

... Note: 1. Exceeding these ratings may damage the device. 2. The device is not guaranteed to function outside of its operating conditions. 3. θ is measured in free air YB1521 MRev.1.1 Recommended Operating Conditions (Note 1) Supply Voltage V Operating Temperature ....... -40℃ to 85℃ Output Voltage ......................... 0V to 15V Thermal Information ............................................ 220℃ ...

Page 4

... Feedback Voltage FB Input Bias Current Switch On-Resistance Maximum Duty Cycle Switching Frequency EN Threshold EN Threshold EN Dimming Frequency Switch Current Limit Under Voltage Lock Out UVLO Hysteresis Over Voltage Protection Thermal Shutdown YB1521 MRev.1.1 Symbol Test Conditions =0. =0V 0mA ...

Page 5

... High Power Step-Up DC-DC Converter & WLED Driver Typical Performance Characteristics Steady State Operation V =5V, 39 LEDS, 260mA IN Startup Waveforms into an Open Load V =5V, 39 LEDS, 260mA IN YB1521 MRev.1.1 Startup Waveforms V www.yobon.com.tw YB1521 =5V, 39 LEDS, 260mA IN 5 ...

Page 6

... Application Information Inrush Current The YB1521 has internal soft-start to limit the amount of current through the IN pin at startup and to also limit the amount of overshoot on the output. The current limit is the peak increased by 4 steps to give a total soft-start time of 160µ ...

Page 7

... In the case of open circuit or the LEDs failure, the LEDs are disconnected from the circuit, and the feedback voltage will be zero. The YB1521 will then switch to a high duty cycle resulting in a high output voltage, which may cause SW voltage to exceed its maximum 18V rating ...

Page 8

... PCB Layout Consideration Proper layout of the high frequency switching path is critical to prevent from noise and electromagnetic interference problems. Due to high frequency switching, the length and area of all the traces connected to the switch node should be minimized. YB1521 MRev.1.1 For smaller output www.yobon.com.tw YB1521 8 ...

Page 9

... High Power Step-Up DC-DC Converter & WLED Driver Package Information (SOT23-5) The information described herein is subject to change without notice. Yobon does not assume any responsibility for use of any circuitry or applications described herein, nor does it convey any patent license. YB1521 MRev.1.1 www.yobon.com.tw YB1521 9 ...

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