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YB1517
Step-up DC-DC Converter & White LED Driver
Description
Features
The YB1517 is a Current-mode PWM step-up
DC-DC converter. It can drive up to 18V at 3.0V
input and 30V at 5.0V input. The 1 MHz 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 5 white LEDs in
series at 3.0V input and up to 8 white LEDs at 5.0V
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.
900 KHz current-mode PWM converter
Built-in internal switch
Adjustable output voltage up to 30V
2.7V to 16V input range
<1uA shutdown current
Internal Soft Start
Drives up to 5 white LEDs
Tiny Inductor and Capacitors allowed
Small 5-Lead SOT-23 package
220mV Low Reference Voltage
Applications
LCD Display Module
White LED Backlighting
PDAs, GPS terminals
Digital Cameras
Cellular Phone
Electronic Books
Portable Applications
Typical Application Circuit
YB1517 MRev.1.0
www.yobon.com.tw
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Pin Configuration
YB1517
Step-up DC-DC Converter & White LED Driver
Figure 3 : YB1517 Pin Configuration
Pin Description
Table 1
Pin NAME
1 SW
2 GND
3 FB
4 CTRL
5 VIN
Description
Switching Pin. This is the collector of the internal NPN power
switch. Connect to inductor and diode. Minimize the metal
trace area connected to this pin to reduce EMI.
Ground Pin. Connect directly to local ground plane.
Feedback Pin. Reference voltage is 220mV. When connecting
LEDs and a resistor at this pin, LED current is determined by
the resistance and CTRL voltage.
Shutdown Pin and Dimming Control pin.
VCTRL > 1.8V generates full-scale LED current
VCTRL < 0.4V chip is off
Switching from 0.4V to 2.0V, 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
Table 2
Order Number
YB1517ST25
YB1517 MRev.1.0
Supplied as
3000 units Tape & Reel
www.yobon.com.tw
Package Marking
Y58 F
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YB1517
Step-up DC-DC Converter & White LED Driver
Absolute Maximum Ratings
Recommended Operating Conditions
VIN ................................................................................. 20V
SW Voltage .................................................................... 35V
FB Voltage .......................................................................5V
CTRL Voltage...................................................................5V
Maximum Junction Temp,TJ (not 2) ............................150°C
Lead Temperature (Soldering 10 sec) .........................250°C
Thermal Resistance (SOT-25, θJA) .......................250/W
Internal Power Disspation (SOT-25, PD)...................... 0.4W
Operating Temperature (note 3) .........................-40°C~85°C
Supply Voltage .................................................... 2.7 V~16V
SW Voltage ....................................................................30V
ESD Susceptibility (HBM).............................................. 2KV
ESD Susceptibility (MM)...............................................200V
Electricity Characteristics
Table 3 (TA=25°C, Vin=3.3V, L=22uH, Cin=1uF, Cout=4.7uF unless otherwise noted)
Symbol
Vin
IQ
(Quiescent
Current)
VFB
ICL
IB
FRSW
DTMX
DTMN
VSAT
Function Parameter
Input Voltage Range
Not Switching
Shutdown
Feedback Voltage
Switch Current Limit
FB Pin Bias Current
Switching Frequency
Maximum Duty Cycle
Minimum duty cycle
Switch Vcesat
Test Conditions
VFB = 0.5V
CTRL = 0V
Iout=20mA,Vout = 6V
Circuit of Figure 2
100% duty cycle
40% duty cycle
VFB=220mV
At Isw = 200mA
Min Typ Max
2.7 16
1.2 1.5 1.7
0.3 1
210 220 230
850
850
20
900 1000
400
1
900 950
85
25
180
Units
V
mA
uA
mV
mA
mA
uA
KHz
%
%
mV
ILKG
Switch Leakage Current
Ctrl = 0.5V
1 μA
VCTL
ICTL
OVP
θJA
VCTRL for Full LED
current
CTRL Pin Bias Current
Over Voltage Protection
Thermal Resistance
Full On
Full Off
Ctrl = 2V
1.7
40
34
220
V
0.3 V
μA
V
°C/W
Note:
Absolute maximum ratings are limits beyond which damage to the device may occur. The maximum
allowable, power dissipation at any ambient temperature is calculated using: PD(MAX)= [TJ(max)-TA]/θJA .
YB1517 MRev.1.0
www.yobon.com.tw
3