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Teilenummer | YB1509 |
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Beschreibung | High-Power White LED Driver | |
Hersteller | YOBON TECHNOLOGIES | |
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Gesamt 7 Seiten ![]() www.DataSheet4U.com
YB1509
High-Power White LED Driver
Description
The YB1509 is a high-power boost
converter. An adjustable current limit, wide
range of input voltage, and up to 40V of
switch voltage are designed to drive white
LEDs back-lighting for large LCD panel. It
can drive up to 10 LEDs in series or 18
LEDs in parallel/series configuration.
The wide application VIN range makes
YB1509 suitable for many types of battery
applications such as Li-ions, Alkaline, or
Sealed Lead Acid batteries. The adjustable
inductor current optimizes the performance
for different output drive capability by an
external resistor.
The LED current is set by a resistor
connected to FB pin. The On/Of duty with
clock frequency from 1K to 100KHz at EN
pin can control the LED brightness
Features
2V to 16V Input Voltage
40V Maximum Output Voltage
Drive up to 18 White LEDs
Adjustable Inductor Current
1µs Constant Off-time PFM Control
1KHz to 100KHz PWM Dimming Control
Applications
PDA, Palmtops and Smart Phones
LCD Monitor
LCD TV
Portable DVD player
White LED backlighting
GPS navigation system
Handheld Game
Typical Application Circuit
VIN= 6 to14V
10uF
16V
10nF
6.3V
EN
Bypass
Iset
1K
VIN
YB1509
GND
22uH
SL12
4.7uF
35V
LX
BZV55-B 36
FB
2KOHM
Figure 1. Typical application circuit
YB1509 MRev.1.1
www.yobon.com.tw
RFB
60OHM
1
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YB1509
High-Power White LED Driver
and going through the ISET resistor to
ground. The higher the ISET pin voltage, the
larger the peak inductor current is built up.
Application Information
Enable/Shutdown
The YB1509 comes with an active-high
enable pin that allows the white LED driver
to be enabled. Forcing the enable pin low
disables the chip and puts it into the
shutdown mode. This pin cannot be left
floating; as it may cause an undetermined
state.
Input/Output Capacitor
It is recommended to use a 10µF capacitor
on the YB1509 input and a 4.7µF capacitor
on the output. Higher capacitance is
allowed to reduce the voltage and current
ripple. Choose low ESR capacitors for the
output to minimize output ripple. Multilayer
ceramic capacitors are good choice for the
input and output capacitor.
Inductor
The appropriate inductor for a given
application is calculated using the following
equation:
L
=
⎜⎜⎝⎛
VOUT
−
VIN,MIN
ISET
+
VD
⎟⎟⎠⎞
TOFF
Where VD is the schottky diode voltage,
ISET is the setting for inductor current, and
TOFF is the switch off time designed for 1µs.
When using this equation be sure to use
the minimum input voltage for the
application, such as for battery-powered
application.
Choosing inductor with low ESR decrease
power losses and increase efficiency.
Diode selection
To maintain high efficiency, the average
current rating of the schottky diode should
be large than the peak inductor current.
Schottky diode with a low forward drop and
fast switching speeds are ideal for increase
efficiency in portable application. Choose a
reverse breakdown of the schottky diode
large than the output voltage.
Thermal Consideration:
When YB1509 is set to handle high switch
current will result in internal power
dissipation and thus generating heat.
Always beware the amount of power
dissipated during operation. To resolve the
thermal built up issue, reduce resistance at
ISET which lower the peak switch current.
Layout consideration
The input capacitor CIN must be placed
close to the IC. This will reduce copper
trace resistance which effect input voltage
ripple of the IC. The output capacitor, COUT,
should also be placed close to the IC. Any
copper trace connections for the COUT
capacitor can increase the series
resistance, which directly effect output
voltage ripple. The feedback resister
should be kept close to the FB pin to
minimize copper trace connections that can
inject noise into the system. The ground
YB1509 MRev.1.1
www.yobon.com.tw
6
6 Page | ||
Seiten | Gesamt 7 Seiten | |
PDF Download | [ YB1509 Schematic.PDF ] |
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